348 parts for rebuild

[Dave N]

Where is the best place to get pistons without getting killed on price and also do big block or smallblock valves interchange with 348 if you resize your heads to fit them
Thanks Dave N.

[models916]

Forged or Cast?

[Gearhead99]

I just bought pistons [cast] and rings from Egge. They weren't priced out of wack to me.

[Dave N]

I'm building a 350 HP. Iam getting low po heads punched out to the bigger valves and will go with the stock comp. 11.25:1 I think originals were cast aluminum with steel struts. also would like solid lift cam as original tripower and 2 1/2 inch exhaust. Who carys good pistons for this aplication. any help on web sites or phone numbers would be helpfull I will probably have to go with 60 overs.
Thanks Dave N.

[CDNpontiac409guy]

Dave N...
You can check our links page, under vendors. There are a few that sell pistons, ect.

My recommendations:
Cam:
M-235578D

With recommended 1.7 ratio roller rockers, net lift at valve, .540"/.554"

Advertised duration, 270/280 deg... @ .050", 235/242
on a 108 centre line

Pistons... I couldn't see cast in an application like that:dunno

[models916]

This guy carries the right stuff.


http://www.bruneauperformance.ca/intro.html

[tripowerguy]

Since you can't see inside the engine and you're keeping the 379 heads with bigger valves why hamstring the engine with an old profile cam. As Aubrey says go the bigger and more modern cam but also cut the vavle guides down so they can take that much lift. Go to Advanced Abrazives web site and they will give you a complete guide to porting heads. You're going to need to take a lot of material out of those 379's to get them to flow. I spent 80 hours on my 379's. :coffee: Roy

[boxerdog]

I had no idea how rough the 379's would be until I started on them. I am not a professional by any means, but I have seen a lot of good ports on other heads which had been done by reputable people. I have done other types of heads, mostly SBC and Chrysler A-engine.

So I have electric and air grinders, burrs, taper rolls, etc. (and I stayed at a Holiday Inn Express last night???) and I didn't hesitate for a minute.

But the 379's I have were really poor in stock condition, it's no wonder that the early 348 struggled in comparison to the SBC. The only good news is that maybe there is room for a significant improvement; I think a lot of you guys have already been down this road with some success, and I'd have to agree that it is very time-consuming!

[Dave N]

Were the 1147 better heads? They look the same to me except valve size. Thanks everyone for the input. and suggestions any one else care to chime in. I'm trying to learn as much as I can.
Thanks Dave n.

[tripowerguy]

1147's flowed a lot better. I think that if you check the volumn of the ports that the 1147 has much more volumn than 379. I know that Lamar says leave the exhaust alone but my 250hp engine with 3X2 and a lame Crain cam pushes my 3900 lb hardtop through the 1/4 mile at 94+ mph. I attribute that to increased flow on my 379 heads. I think that if I had gone to forged 11.1 pistons and a cam like Aubrey is talking about it would push 100 mph. I took a lot out of the exhaust side just leave the floor of the port alone except clean it up a little leave the shape alone.You can take a lot out of the pockets of the port intake and exhaust and cut down and shape the guide bosses coming into the port. Just don't polish up the intakes leave them roughed up this keeps the intake charge swirling. I polished my exhaust to a mirror shine. I also tried to straighten up the ports in the intake manifold but you don't have much to work with. This was the first set of heads I ever ported and I know if a porting service looked at them they would tell me that I made mistakes but I'm pleased with the result.:clap Roy

[models916]

333 truck head has better ports and flows better stock than the 379. Cheap most of the time.

[tripower]

Were the 1147 better heads? They look the same to me except valve size. Thanks everyone for the input. and suggestions any one else care to chime in. I'm trying to learn as much as I can.
Thanks Dave n.

Models is right. The 333 heads would be a better place to start. I think you would be wise to read some of the old threads here. There is a lot of information to help you decide what would work best for you. There has been a lot of improvements in the performance parts available. Here is a good thread that should answer a lot of your questions. Good Luck.

http://www.348-409.com/forum/showthread.php?t=8778&highlight=bore+348

[tripower]

Here is some good reading as well...

http://www.348-409.com/forum/search.php?searchid=141011

[Dave N]

Thanks everyone for there input. I've decided to use a set of 409 817 heads instead of the 379s, I have to go with the cast pistons for some cost savings I'm not really building it to race just get on it now ad then. I want it to be streetable though and to sound like a stock 350 HP. motor is the cam your talking about good for that application Aubry or do you have any other advice on a cam set up for my engine.
Dave N.

[CDNpontiac409guy]

Sure can, Dave...
I would step down one notch from the one I recommended above.
You will require a real 10:1 compression ratio... maybe a LITTLE more. Small valve relief in piston is also neccessary. Remember that if you buy any "regular" pistons, the use of the Felpro composition head gaskets will cost at least .3 of your compression ratio. The slightly larger cc's of the 817 heads will also take away a bit. So, you should request a 10.5 - 11:1 piston.

With the cast pistons, I'd limit RPM to 5500.

Please PM me about the cam... I'll "create" something:deal

[jr.W]

Aubrey I thought that only the 333 heads had a combustion chamber?
Why would the 817 heads lower the compression? Is there something
I haven't learned about w's yet.:dunno :) Just trying to learn more.:D

[CDNpontiac409guy]

no no. Jr... I'm "splitting hairs" here:rolleyes:
The 817 is about 1.5 cc's bigger in the combustion chamber, simply because of the larger valves, which are recessed into the head ( form part of the combustion chamber )

Putting my Stocker together... guess my head's just in that "mode":stooges

[jr.W]

I hadn't thought about the valves being below the deck just inexperience
with W's is all.:takethat How far below the deck is average for the valves?
Also how big is the valve recess area ?
Are the cast pistons fairly reliable @ 5500 rpm or less and who makes the best cast piston for the 348?
Sorry for all the questions just trying to gain more knowledge.

[tripowerguy]

Show Cars has cast pistons I don't know if they have the steel strut cast in above the wrist pin. Egge sells cast pistons that have the steel strut. Chevrolet put steel struts in the cast pistons and for some reason the reproduction industry dropped the ball. I suppose it was a way of cutting costs. When you order just make sure that you order the ones with the struts. If you go with the 9 1/2 comression pistons you will have no valve relief so you are going to be limited on valve lift. I don't know if anyone makes a cast 11 1/4 compression piston but they should have the valve relief. I am running a Crain 409 replacement cam with 9 1/2 compression pistons. This cam has .434 lift with 280 degrees duration and is a solid lifter cam. Solid lifters are no problem anymore, throw away the stock rocker arm nuts and put poly locks on. I have checked my valves over a three year period and they have never needed adjustment, so the solid lifters are just as maintenance free as hyd. Now back to valve lift, with mine the valve opens faster than the piston travels away from it and comes within .060:eek: of the piston. That is okay because I have very good valve springs [Comp Cams]. The cam is lumpy about like the old Corvette Duntov cam. A good cruise in cam. It would be ok for a stick shift trans but is a real dog out of the hole with an automatic. I know you asked about pistons but what cam you're running dictates what pistons you run. If you want to run it through the gears once in awhile and go to cruise ins then the cast pistons would be fine. As far as 350HP cam , I doubt that you're going to find a cam that duplicates the exact geometry of the 350 hp cam. You'll get a generic 350hp, 409 hp solid lifter cam unless you can afford to have a one of custom ground cam. If you don't have the 817's you are going to find them somewhat expensive so be prepared to pay over a $1000 for a set that are going to take another $500 to get set up. The 379's with bigger valves and and good pocket porting will do you to 5500 rpm and be a good cruiser. It is all in what you want to use the car for. I hope that this long dissertation hasn't put you to sleep.:rolleyes: Roy

[models916]

Crane and Comp charge the same for Custom grind or off the shelf cams. Call the help line and get a recommendation and a part number. You can order it from Jegs or Summit. Takes about a week.