four bolt mains for a 409?

jim_ss409

Well Known Member
Supporting Member 5
We just picked up a good 1964 truck engine and we're thinking of using the block for a race only engine. I've been thinking that billet 4 bolt main caps might be a good idea but I'm wondering if they're really necessary? The engine will likely have a 4" stroke and about 13 to 1 compression. It'll be naturally aspirated and be shifted at less than 7,000rpm.

I notice that Lamar Walden likes to use billet caps, then bore the mains out to Big Block Chevy size. He also leaves the crank snout at BBC size and uses a special front cover with a BBC sized seal. If we did go with the billet caps do you think this might be the way to go?

Also I remember someone saying that Eagle was coming out with a 4" stroke crank for the 409. Does anybody know if they're available yet?

I'd appreciate any opinions or suggestions.
 

Ronnie Russell

Well Known Member
Supporting Member 2
Jim, models reports Eagle part number # 440940026135 as being the 4 in. stroke for 409. It would take a phone call to ensure if it is 409 main size, etc. All machinists will recommend 4 bolt mains. Most say to line bore for big block crank size. As you know, we use 409 main size and two bolt mains. 13 to 1. Only spin it to 6,200 rpms. Tough question. The BWR block will solve all of these issues, but may be a while before it is ready. The sooner the better. Good luck with your decision.............:)
 

desapience

Well Known Member
Supporting Member 2
splayed 4-bolt mains

We just picked up a good 1964 truck engine and we're thinking of using the block for a race only engine. I've been thinking that billet 4 bolt main caps might be a good idea but I'm wondering if they're really necessary? The engine will likely have a 4" stroke and about 13 to 1 compression. It'll be naturally aspirated and be shifted at less than 7,000rpm.

I notice that Lamar Walden likes to use billet caps, then bore the mains out to Big Block Chevy size. He also leaves the crank snout at BBC size and uses a special front cover with a BBC sized seal. If we did go with the billet caps do you think this might be the way to go?

Also I remember someone saying that Eagle was coming out with a 4" stroke crank for the 409. Does anybody know if they're available yet?

I'd appreciate any opinions or suggestions.

My 482 has splayed 4-bolt mains -- not the straight-bolt 4-bolts. One minor problem I ran into was in the clearances for the 3 center mains (the end mains remain stock), with the custom made STEF's oil-pan I'm running. The scrapper screen had to be very slightly notched up near the passenger-side oil-pan rail.

My compression ratio calculated out to 11.3 (bored the truck-block out .060"), with the crank's main journals also remaining stock 409, with the SBC snout diameter. IMO, staying with the 409-sized journals mandated it sensible to use the 4-bolt mains (straight or splayed). I used ARP BBC main studs for the inner bolts, and ARP bolts for the 3 splayed pairs. My 583 heads are also held by ARP studs, not bolts.

I've previously had and ran a stout 468 c.i. BBC roller-motor with stock 2-bolt mains, without any problems what-so-ever. I was advised that so long as I stayed below 700 h.p, I'd have no problems. Although not ever dynoed that engine-combo was designed to be providing a very concervative 550 h.p. The engine was not babied by me in the slightest way, and when later disassembled, the crank journals and bearing wear remained unmolested, and line bore also remained dead-on. I easily sold the disassembled engine for top dollar.

Given your level of expected compression ratio, and the focus on racing only, IMO, you should at the very least, go with 4-bolt mains with a stock 409 diameter journal, and not a bad idea to go to BBC journal sizing. It can't hurt. However, I'm not sure about how ovrboring would effect the strenght of stock 409 end journals, or even if 4-bolt end journals are even easily available.

Also, if using a billet aluminum timing cover, whether with a SBC, or BBC sized snout seal, a problem can also emerge with the front oil-pan rail groove sealing area -- that is, IF you also go with an aluminum oil-pan (STEF's). I tried going with a billet timing cover mounted to a STEF's oil-pan, and the extent of the needed further modification to the timing cover, combined with the accompanying necessity for dealing with the lacking clearances for mounting the water-pump, forced my decision to go with a stock timing cover.

The significantly thicker billet timing cover would have necessitated shimming out the WP legs 1/4" (3/16' shim, plus two extra gaskets), the crank pulley, 1/4", and on to having to diddle with also shimming/adjusting the alternator, and/or A/C compressor 1/4" forward. One solution could have been to notch my billet cover, and maybe even slightly notch the WP (if I used the Rejeski pump I also have -- but, that would have been the easy part. The real problem was, again, the front STEF's oil-pan & timing cover seal interface. I believe that problem would not have necessarily existed if I were able to use a stock 409 oil-pan though. :dunno

I hope this helps with your decisions.

Denis
 

bluescreamer

Well Known Member
Supporting Member 1
Four bolt main for a 409

Jim
The last motor I build 470ci we used a four spayed bolt main
made by Pro-Gram Engineering. BB409C4A. http://www.pro-gram.com
Had no problem with main. Be careful installing bolt holes are very close
to main oil galley. Use of a bottom tap is required. also is close to the side
on the main web. We used a 4 in. Callies Crank and cut the mains down
to 409 spec's.
We broke a cylinder this past Labor Day, and the motor required a
sleeve to be installed. When I took motor apart the crank and mains looked like new.
As I'm typing, the motor is being reassemblied all that has to be done
is bolt the heads and intake back on.
It's your choice, but like Denis indicated the stock Arma Steel Main on a
09 should support 700 hp. Compared to a sb motor main there is alot
more metal on one of our Mains, and look what they have as a potential
of producing in hp.
Allen
 

Skip FIx

Well Known Member
I've seen one with BBC 4 bolt main caps not the billets. Proabably from a BBC going to billets. then bored out to BBC journal size.

One advantage to the smaller 409 mains is bearing speed and friction. Smaller bearings are better for the decrease in this. If you look at the Engine Masters competition motors many of those guys machined special bearing spacers to use smaller bearings on the mains and rods.

I know of alot of fast race cars with 2 bolt main BBCs in them.
Another thing to consider is "Hard Block" in the water jackets, at least to the bottom of the freeze plugs. It ads support in the lower block. If youlook through the freeze plugs you can see there isn't alot of support around the bores. Alot of my Pontiac buddies even report cooler water temps as the stabilization helps some of the piston friction, especially as you ge longer strokes that side load the cylinders.
 

jim_ss409

Well Known Member
Supporting Member 5
Thanks for the input guys. And thanks for posting that link Allen. I was thinking along the same lines that the stock caps with ARP studs would probably be okay but billet caps would be a little extra insurance. I see that Pro-Gram also makes a billet front cap but I think that just the three centers should be plenty strong enough. http://www.pro-gram.com/catalog.jsp That would also leave the stock front and rear caps as a kind of guide for the machine shop when I get it line bored.
I'm also leaning towards staying with the 409 spec. crank with a 4" stroke because I want to use the same gearing and torque converter I've got now. I'm crossing the line at about 6,200 now and with the extra power I'd expect it to be about 6,500rpm. I guess I could give some thought to a bigger 4.25" stroke with long rods though. (504ci):scratch The extra torque would be nice but I think you'd want to keep the revs down below 6,500 with that much stroke.
SkipFix, Hardblock seems like a good idea especially with a longer stroke. I have no experience with it but I imagine that it would be best to put it in before machining the cilinders.
 

bluescreamer

Well Known Member
Supporting Member 1
four bolt main for a 409

Jim
Yes I'm using 3 main caps. that should be all that you need.
What gearing is in the 3rd member? I weight in at aprox 3950#
and have a 4.88 gear and 30 inch tire. Shift around 6600 and cross
finish at 7150. that is with both motors 450 and the 470.
This fall with the small motor went a 10.44,10.47and 10.48. air
was good!:clap :clap :clap
If you have deep pockets go for it. properly wouldn't have to twist
motor as hard with a bigger crank.
Allen
 

oil4kids

Well Known Member
Suggest you redrill the oil galleys to big block size and use the 2 quart truck type oil filter canister

and use the new high strength G10 Milodon pump that is a small block pump that uses big block inlet and parts part #18770
 

Skip FIx

Well Known Member
Most just add 4 bolt on the 3 center mains.

Another thing to think about using a bigger stroke and bigger CI the heads just can't feed it and they are the rpm liiting factor. veen a good set of 690/583s are hard pressed to really feed a stroker motor. Most GOOD SBC aftermarket heads flow as much or more.

Allen what chassis did the 30" fit? Surely not a X frame. I know my 64 (and most I've seen) had to have the front fender lip hammered just to fit a 28" tire in.
 

Ronnie Russell

Well Known Member
Supporting Member 2
Skip, Have noticed you mention several times how the 690s dont flow enough to feed a stroker motor. There are many strokers running around the country being fed by 690s. I have seen them run and in my opinion, they are being fed well. Sure, more flow would result in more horsepower, but they dont appear to be starved to me. I think my 482 with 817 heads make more torque and horsepower than a 409 and would bet it makes more than some 409s with 690s. Someday soon we will have 409 heads that will flow much better and that will be a good thing, but I would never advise someone not to build a stroker motor because in your opinion, the heads dont flow enough. How much is enough? Enough for who? You ? Me ? I am happy with mine and I think there are others who are not sorry they built a stroker also... Just my opinion.......:)
 

ratkiller

Active Member
Hey Jim,

I had this same conversation with Curt Harvey and he said that without blowing or squeezing the engine over 600+ hp it just wasn't worth drilling into the block. He backed that up with saying he'd never seen a 2 bolt main broken or stressed from standard stroked sizes we're all used to. He also brought up the point that the areas where the 4 bolt would be drilled into has a webbing cavity on the backside and isn't solid casting all the way through. So it wasn't clear if the 4 bolt would actually make a difference or not. MHO says no need to take extra material out of a limited resource if you don't need to...

I say no, keep it as is.
 

Skip FIx

Well Known Member
Ronnie I'm talking mainly in the race sense for max power, and that usually means higher rpm range. He mentioned a race motor build. Us Pontiac guys have been living with lower air flow also. A set of 690s flow about what a set of RAIV (the best cast irons)Pontiac heads flow, lucky to make it to 300 cfm with alot of porting, I've done them both on a flow bench. Out of the box Brodix Track 1 SBC heads flow that and are only feeding 350-400ci! A BBC around 340 to 400 for the aftermarket heads.But the less flow on a larger ci motor drops the peak torque and HP rpm down, regardless if it is bigger from stroke or bore, our Pontiacs are bore limited due to spacing and wall thickness until you get to aftermarket blocks. That just makes the rpm range different and the strategy for going fast different for cam,gearing, convertors etc. You have to look at the whole package and integrate your parts selections.


I am all for stroking a 409 and mine will be even with 690 heads. I just think going to a 4.25 stroker over a 4.0, the stroke won't be the rpm limiting factor where your peaks are, the head flow will be, that's all I'm saying. That's why the aftermarket Edelbrock and now even higher flowing Tiger/KRE High Port headed Pontiacs(these new ones can get closer to 400cfm with alot of porting) are making more HP in race form , and some even competitive now in the heads up 10.5 classes with the BBC boys. But they are twisting alot more rpm also than traditional Pontiac race motors have.

Here's a formula for you with CSA(cross sectional area in sq in).Peak torwue is generally when air flow is around 240-260 ft/sec.
Peak torque rpm= CSA x 88200/cylinder volume.

I just measured the throat area on a 690 I have in the garage 1.96 so the area is 3.017(port dimensions of 2.48x1.265 give 3.137 but we are looking for the smallest CSA, might even be up at the short turn and not the throat I measured)

Divided by a 409 cylinder of 51.125ci its 5204rpm, now make it a 480 ci stroker(round number) with 60 ci/cylinder and the rpm drops to 4434rpm for peak torque rpm!

So if you are building a lower rpm torque motor like us Pontiac guys have been doing for years, yea we have enough flow. But to feed a 480 inch motor with a 300 cfm head most race motor builders will tell you there isn't enough head flow. Heck I'll bet those factory truck 496 BBC with little oval port Votec heads flow alot more and they are designed for torque.

My 310 cfm Edelbrock headed 455 can run with alot of BBC at 10.99 but my 6200 shift points are different than alot of other 455s that shift at 5700. Mine stil only has a 239/247 @ 0.050 hydraulic cam! bet most of those BBC boys I beat are running alot bigger cams.

I even remember an article years ago in a magazine by one of the 409 guys maybe Curt Harvey that also stated our heads and intake(especially single 4) limit our strokers.
 

Ronnie Russell

Well Known Member
Supporting Member 2
Skip, All your numbers are interesting and no doubt correct, however you are missing the point. If horsepower were the main focus of racing, then we would be using BB Chev. We race 409s because they are unique and because we choose to. No matter which engine you choose, there is one thing that is always true------ There is always someone faster...... Barry's car will run 9.70s today and I mean that literally. 2,800 lb plus 200 lb for fat Barry. At 3,000 lbs , it does not take a lot of horsepower to manage 9,70. I think it is safe to say by dropping cubic inches back to 409 that e.t. would suffer. We will continue to race and not worry about head flow formulas. When better heads come along, we will use them and when possible to use more cubic inches, we will take advantage of that also. Another thing is also true. Opening day of the 2007 season, we will be racing a W-head car and making plans for the next generation motor. Looking forward to seeing your 409 run,,, someday.......:cheers
 

models916

Well Known Member
Supporting Member 7
squirm around

2 bold mains squirm around on long stroke high rpm engines. Most just wear out the mains early, some will spin a bearing. I have not seen one break.
 

desapience

Well Known Member
Supporting Member 2
Fast-burn ZZ430 SBC heads

Skip, All your numbers are interesting and no doubt correct, however you are missing the point. If horsepower were the main focus of racing, then we would be using BB Chev. We race 409s because they are unique and because we choose to. No matter which engine you choose, there is one thing that is always true------ There is always someone faster...... Barry's car will run 9.70s today and I mean that literally. 2,800 lb plus 200 lb for fat Barry. At 3,000 lbs , it does not take a lot of horsepower to manage 9,70. I think it is safe to say by dropping cubic inches back to 409 that e.t. would suffer. We will continue to race and not worry about head flow formulas. When better heads come along, we will use them and when possible to use more cubic inches, we will take advantage of that also. Another thing is also true. Opening day of the 2007 season, we will be racing a W-head car and making plans for the next generation motor. Looking forward to seeing your 409 run,,, someday.......:cheers


I have an unfired SBC ZZ4330 clone -- w/the fast-burn heads, LT4 cam-kit, etc. It's awaiting installation into my 31 Chevy 5-window coupe.

At the time they were 1st introduced, the 430 h.p. ZZ430 was the highest horse-power Gen I 350 GM ever produced (only 430 of them, at that).

When I first received the fast-burn heads, I was startled at the smaller size of the valves! GM touted their great results as being due to the speed of the charge entering ther combustion chamber, and the heads came with a warning that it was counter-productive to port the heads of or play with increasing valve sizes. Just botl them on, and voila... big, power (albeit with proper headers, cam, etc)!

I do not have the sizing numbers on hand as I write this, but, I also had a set of Edelbrock's high-horse-power heads with the bigger vales (not the new fast-burn-like E-tecs). The difference was obvious -- the fast-burn heads were using smaller valves. As I said, I do not know the runner lengths of either at hand.

Question is, is simply chasing port and valve sizing, versus somehow optimizing the speed of the charge (smaller ports, and straighter runners), something that might also give big rpm/horse-power gains to a stock c.i. 409? Squish zones, shape and area, is also a focus for the ZZ430 fast-burn heads...

Anyone care to bring more understanding about this to this discussion?

Denis
 

rstreet

Well Known Member
Supporting Member 17
Denis
I recall a younger guy in Texas was doing head designs for Ernie Elliotts engines and they "discovered" something involving velocity in the Ford NASCAR head for approximately 2 years until the competition caught on. This was in the early 80's but I don't recall any of the details other then some other builders called them "peanut" heads because of the unusual valve sizing and port shapes.
I belive the guy in Texas has since died and I don't recall his name but he was doing it with a computer program he had developed.
As to if they worked I recall the afternoon at Talladega that Bill's Ford went down 2 laps very early due to a loose pressure steering line. He ran the field down without a drafting partner and won the race!!!! Virtually unheard of before then. He was running those heads that afternoon. I wish I was more knowledgible about them but this concept are in your heads because later he(the Texas Kid) did development work for GM. Also Tom Fileman(Flagship Marine) formally on Long Island, N.Y. now down in Punta Gorda,FL. did head developemnt work but Tom's people concentrated his GM work for Mercruiser.
Maybe someone from the Texas area or Georgia will know details or even have some of the heads. Heck Tommy Nolen probably has a few:D
Robert
 

Skip FIx

Well Known Member
Ronnie, I whole heartedly agree a stroker 409 can run good numbers, the same way lot of Pontiacs run good numbers before the better flowing heads came out. I still love them both and will run them over a BBC also, it's cooler to be different. Even the current Pontiac Super Stockers today will take HP over torque any day for their race cars. You all need to let me know when you race down this way! Shoot my 150 lb body could pick you up a little time if I drove it! Most of with these classic motor do do it for the fun and going as fast as we can.

I just think for a race motor there will be a point of limiting returns adding more stroke with a 300 cfm head. There are bigger stroke cranks we could stuff in our block like a 4.50 also , but look at the old Caddie 500s-low rpm torque motors(unless you get the new aftermarket heads and intake for them!). I think a 3.76 or 4.0 though is getting there.

I'm just saying for a really good "big" motor we don't have the heads so you have to plan the whole thing for cam, convertor, gears for the lower rpm torque.

Dennis-another area you touched on for current motors street and race is all of those details, Quench, swirl, shape.Wet flow porting. Unfortunately our old motors we can only do so much with what we have to work with in their design parameters of port shape before you hit water, unless you want to spend big bucks like the Super Stokers do as they can port but have to keep the "stock" port ccs, so rewelding or alot of epoxy is used. Some of the aftermarket Pontiac heads have a better combustion chamber using current thoughts there, not the Edelbrocks though.

Quench is a big deal and I've personally seen it make a big difference especially in regards to timing a detonation, don't run a 0.100 down deck height. We have the advantage that just a really custom designed piston for our 09s could really make use of some of that. Look at alot of the current race heads-small chambers maybe 50cc for big motors. Just small areas around the valves like we have, they make it up in their "reverse dome" pistons. Better flame travel than a big chamber and a dome piston. Maybe those old Jahns Fire Slot 409 pistons were just way before their time!!

So a 409 piston that with a reverse dome around the valves only gives our nice flat head 0.039 quench all around the valves would give us better fuel atomization in our in block chamber. For a really effecient dish you could put a slightly biased angle in the dish toward the exhaust valve. Some of the NASCAR boys do this on theirs.

We should really be sure at least the top part of the piston is close to 0 deck. I think Aubrey's pistons are supposed to use some of the new thoughts in them if I remember our conversation correctly.

The flow into the chamber is also a big deal using swirl to keep fuel in suspension better. Without a wet flow bench we really don't know what the porting wil do to that. That is the new frontier on the race front Mondello and Reher and Morrison have designed some wet flow benches. They were finding big HP differences in heads that flowed the same on a dry bench because of this. I've heard porting our 09 heads can often be counter productive also.

Some of this new technology we can bring to our "classic" motors some we can't with out major redesigns. I always like the tear downs of any brand motor in the Engine Masters Competitions to see what new technology is being used in motor closer to what we do than Pro Stock type motors. FYI a Pontiac built by Kaase, a nationally know pro motor builder of Fords, finished second this year by one point, 4th last year. So our classic motors can be updated!

The biggest addition in tuning even our classic motors is a wide band O2 sensor to really see what your carb is doing, Better than reading plugs. The Engine Masters guys use one in every header tube for evaluating intake manifold mods for fuel distribution!
 

desapience

Well Known Member
Supporting Member 2
W's were puzzling to even the original GM engineers

Back a few years ago when I first got into W's, I read an in-depth article regarding how the original GM engineers were taken aback by how the W's reacted to what was then current thinking in making power. What they had learned with making power for the SBC's did NOT work similarly in the W's! This, of course, had everything to do with the W's having their combustion chambers in the block.

I know I still have the article somewhere... If I remember correctly, the GM guys still had not nearly fully developed the W's when the early BBC came along.

Cam technology and the fact that new ideas in cam profiles can almost be instantly realized, farily inexpensively, by simply ordering a custom grind, ala carte, seems a logical approach to finding more power for the W's.

Cylinder-swap cams seem to have gone by the way-side.., has anyone heard of any such cams used in the W's?

It seems to me what with the call for new aluminum W heads (and intakes, or even pistons), a lot of their design may simply duplicate older less efficient technology, rather than delving into uncharted ground.

"Plug & Play" fuel injection systems also are gaining ground.

Go to>>> www.massfloefi.com Has anyone seen a system like this on a W"

Denis
 

Skip FIx

Well Known Member
New cam profiles are where we can really make good power easily and probably be easier on the valve train. Quicker ramps for more "area under the curve" for flat tappets. Hydraulic rollers for even easier quick ramps. There are even alot more "street" solid rollers that use oiled roller bearings and lower seat pressures.We already have pretty high ratio rockers which give shorter seat duration but quciker valve action and "area under the curve".

Cylinder swap cams are better for single plane intakes where 5-7 firing right after each other are robbing each other. Not as big a deal on a dual plane, maybe that M/T though! It also helps a little on loading that rod journal when 2-1, 4-3 fire back to back stressing #2 main. But then they don't sound the same either with the swap.

Lighter valve train (valves, springs, retainers) are a real good thing on longevity. The new beehive springs and their smaller retainers are a new innovation. Titanium valves with smaller stem valves for the real exotic light weight.
 

jim_ss409

Well Known Member
Supporting Member 5
From some of the tests I've read I've gathered that a stroked engine will often make less peak horsepower than a non-stroked version of the same engine. But of course the stroked engine will make it's horsepower at a lower rpm. And I think I understand what Skip Fix is getting at when he suggests that increasing the cubic inches without a corresponding increase in head flow would reduce the potential hp gains.
In my particular case we're crossing the finish line at about 6,200rpm and 122mph, and if we bump up the power enough to get us into the mid 10's we'll cross the line at about 6,500rpm and 127mph. So I'd like to aim at keeping the peak horsepower below 6,500 so that the present gearing and torque convertor will still be okay. I think a 4" stroke or possibly even a 4.25" stroke would get us in the ballpark and if we later upgraded to the new better flowing heads, I think they'd work well with the extra cubic inches. Right now we've got a 4,000rpm convertor, 4.11 gears and 29.5" tires. There's a fair bit of slippage caused by the convertor though, maybe as much as 8 or 9 percent so the 4.11 gearing kind of acts more like 4.44 to 1.
 
Top