452 CID 409 W/ Bob Walla Heads & Speed-Port 7000 Intake

[CDNpontiac409guy]

This is the big one for me. I have limited experience with the more radical, race oriented stuff. This particular engine is destined for street use... albeit marginal. My customer says that his current 450 HP engine is fine, but just doesn't deliver that gut wrenching ride that he's looking for.

What is in place:
409 car block, .060" over, 12.5:1
3.766" stroke ( 366/396/427 crank )
6.386" rods
Stef's oil pan

Just received a set of Bob Walla 409 heads... the CNC ported version.
a few photos:



These came to me as you see them here, with Bob's own guide plates, arp studs, and 11/32" stem PEP valves.



Bob Walla's heads don't have the mini combustion chamber, and the valves seat slightly above flush with the gasket surface. May be necessary to add a little more flycut to the valve reliefs in the pistons... which is OK, because losing a bit of compression ratio won't hurt.



The exhaust ports / bowls in these heads, are completely beyond anything that could be done with a stock head, or Edelbrock heads. These things are something



The intake port floor takes a pretty good up-swing, and then rolls over high into the back side of the valve.
I believe was 340 CFM @ .600" lift.
These are going to take a little port matching.



Can't tell from this photo... but the seat to bowl blending is flawless !

 

[CDNpontiac409guy]

A few more photos:



Here are the Bob Walla 409 heads, beside the set of Edelbrock heads that I just received for a different build ( 448 CID, 10.5:1, modest hyd cam, Speed-Port 7000 intake )

And below, a few photos of the top end package that will be on this engine:



This is Speed-Port 7000 intake manifold number 004



Have a number of valve springs to choose from. Obviously, the heads will receive hardened spring cups.



Looks like a team to me... like spaghetti and Bolognese sauce

 

[CDNpontiac409guy]

This engine is going to be pretty aggressive.
Where I'm having difficulty, is with camshafts... and I ( and my customer ) would sure appreciate help and guidance with selection, of the mechanical roller that will be used.
We're looking at something like 256-264 intake / 260-270 exh duration @ .050".
Would like a modern, aggressive ramp. shorter seat timing.... but that has dangers.
My experience with aluminum heads and mechanical cams, showed that when the engine warmed up, the valve lash increased dramatically.
If a cam has a short "cushion" for lash... being .005" over spec when the engine is hot, can be catastrophic.

Please, if you can help with this, let us know !

BTW, yes, this IS the engine that is going to be used for the dyno testing of the various intake manifolds.
At this point, a stock single 4bbl, Edelbrock 4 bbl, stock 2X4 bbl, Edelbrock 2X4 bbl, and the Speed-Port 7000 4 bbl.
For the dyno, we'll be using the headers from my Stocker.... 2" stepped to 2 1/8", 34" length, into 3 1/2" collector.

In the car, we're hoping that the engine gets a set of Jardine 2" / 2 1/4" Tri-Y's.

 

[Ishiftem]

As long as the valve isn't off the seat when it's cold, I don't see a problem. The cam I use is 254/260 so it will be interesting what the different intakes do.

 

[61BUBBLE348]

 

[chevytaylor]

 

[BubbletopMan]

Aubrey,

The cam that Crane manufactures for GM for the 572/720 hp crate engines appears to be an easy cam on valvetrain parts and those engines have approximately 12:1 compression. The cam spec's are as follows:

Lobe lift: .420" Intake/.420" Exhaust
Duration @.050" tappet lift: 266 Intake/274 Exhaust
Duration @.020" tappet lift: 298 Intake/306 Exhaust
LSA: 112 Degrees

Granted, for a "Hot Street/Strip" piece as this, I wouldn't personally use a cam with this much lobe lift, but the profile has shown over time that it performs well and is not abusive(they don't even run stud girdles on these). These engines generally don't need a lot of RPM to make peak power, so it may be a good fit for your 452. With aluminum headed engines, I generally see a .007"-.008" growth in lash from cold to hot. I would think a solid roller in the .660" lift with these characteristics would give your customer that gut wrenching feeling he's looking for and should top out somewhere between 6,000-6,500 RPM.

Jeremy

 

[CDNpontiac409guy]

Thanks, guys...
Yes, Jeremy, that is about the same "growth" that I saw on a BBC. When attempting to adjust hot, to get the lash right, the heads cooled enough during the process, that the lash would shrink by .005" + . A quick ramp cam doesn't like that.
From looking at the specs on that 572 cam, it appears that it does not have a quick ramp. May be a hint right there
That .650" - .670" net lift at the valve ( .670" - .690" advertised lift ), is what I was thinking too.

However... RPM... HHHMMM
I think this shorter stroke engine is going to see higher RPM. Anticipating that peak HP will probably occur at no less than perhaps 6400- 6500 RPM.... putting the shift point around 7000.
maybe I'm full of it

 

[boxerdog]

Here is what I came up with:

Crower roller

advertised 290/306
at .050 260/266

LSA 107* install 103*/111*

lift with 1.7 rockers .651 / .676
lash .026 .028

 

[303Radar]

I can't wait to see the dyno results, especially considering the over square of the combination!

 

[Quickshift409]

Please tell me why you would need over 600 lift with a small cu. in. engine. The combustion chamber only holds so much air.

 

[BubbletopMan]

Aubrey,

I agree your combination should RPM higher than a 572. They don't need to turn much with a 4.375" stroke. It's been my experience that with increased cubic inches and longer stroke, things tend to happen sooner. Unless of course one chooses to run a huge intake port, then they must spin it to the moon to create enough port velocity. With the duration of the aforementioned cam, I should have factored in the difference in engine sizes. A cam with these duration numbers, the RPM band should be 3,500-7,500, depending on stroke, rod length, and piston mass. It's very similar to a cam I used to buy from Herbert (CB6F), and that's the area it generally ran well in.

Jeremy

 

[63 Biscayne]

 

[CDNpontiac409guy]

What the heck is with all the popcorn around here ? You guys are gonna get fat.

Perhaps not quite that high, Jeremy, but yeah, that's what I'm thinking.
Shan... Here's how I describe it:

More lift = more opening for air to get by = more mixture gets into cylinder = more force is created during combustion = more torque is produced = more horsepower is produced.

The area under a valve at full left, could never approach the area / volume of a port / runner. That opening will always be the pinch in the "hour glass".

 

[Fathead Racing]

What's your quench? Can you open that up a bit to be safe and still keep it under .045? My solid roller is 254/256 @.50. 474 ci. Runs pretty good with a big lope, car shakes likes dog crapp'en razor blades!

 

[CDNpontiac409guy]

Ray... the pistons are .004" above deck. So, I have about .039" to the head. Pistons have a .200" deep valve pocket... perhaps enough.
I'll get a couple photos of the pistons.

 

[61 Bubble]

Aubrey, this honestly way above what most have any "real" expertise with, and then when you compound the fact that you will be using this as a mule for other top ends, might be best to try and contact someone more knowledgeable in this area? There are a few I could recommend on this.

Chris Straub from Straub Technologies, Mike Jones from Jones Cam Designs are two off my head. I also have a guy in Toronto who "might" look into helping with this and there is another guy off Yellow Bullet you could contact. Only issue I see is getting these guys ALL the info for every aspect of the build to make the best decision, and your WANTS.

I would figure that RPM range with the solids would be around 7000 and shifts around 7300/7400? IF your really thinking of keeping the RPM down to 7000 MAX and under, an aggressive hyd roller might be your ticket. FYI the guy in Toronto has a pump-gas 496 hyd roller with OEM sq port heads and 'OEM '163 intake that makes 725+ on the dyno. In the El Camino that car TOURS the car shows driving 1000+ miles each way too.

 

[CDNpontiac409guy]

Yes, John, you're right, this engine IS going to go through a "mule" stage. I'd expect some 20 pulls anyhow.
I've been around this forum for a little while... I'm sure there are a few guys here, who may have experience with this level of valve train demands. Hope to hear from them

hydraulic roller ???
HHHMMM... I'm gonna run with my gut instinct on that one. .. the oxymoron of performance engine building...
roller lifter to follow more aggressive ( efficient ) ramps.... hydraulic mechanism that can't tolerate the aggressive ramps ( at RPM ).

This one is going to be a learning curve for me, for sure

 

[61 Bubble]

Aubrey, gonna mess with ya a bit. Think like this:

Steve's 496 mentioned about. 725+Hp with GM STEEL heads and GM alum intake. Car can run 1000+ mile trips with 20+MPH to boot.
"Crazydaveracing's" 509 (GM 502 bottom end, AFR 305 heads...Straub hyd roller...11.4 to 1....made 764 at 6200.
2008 Z06, stock bottom end, PORTED heads and intake, 800+Hp with OEM hyd rollers but different cam couple were done that trap 143-145 range on DOT tire

There has been a lot of tech found in the hyd roller now. I think it just might be more forgiving with various top-ends on there and less proven to having complications yet will give a variety of combo's a stable, long term platform on which to base ones perforance. Sorta one less piece off your mind to think about. And since you really have no RPM to speak of.

BTW you want to talk cams and RPM, well check out the car I'm crewing on next weekend:

397" SBF Aussie Pro Stock Engine with a 5 speed liberty @ 2860 lbs. 8.117 so far first weekend out N/A. launch RPM "around" 9800 and keeping the rev's down for now to 10,400/10500. Should be running 10,900 RPM to take full advantage of the motor. NO hyd roller. This is my playground and where my backround on engine performance is

 

[CDNpontiac409guy]

Geez, John, those cars are just sickening... but MAN, what a handful !

Won't be no hydraulic roller here, for sure.
This isn't one of those long arm combinations. Nor is it really very big ( 452 ), considering the top end that'll be used. To make use of that, the engine will need to see 7000+... reliably.