Camshaft question?

[rluck9277]

I am rolling a few ideas through my head of what i want to do this winter. I picked up a 3400 for my 2003 Malibu, and planned on either doing a Milzy Motorsports Stage 1 or stage 2 kit, or getting one of the 3500 top end swaps from here. That descison will all boil down to money, but if i went with the 3500 top end swap from the store, I was thinking of putting in a new camshaft. I know from my previous experience that a gen 3 3100/3400 use the same camshaft, what i was wondering is if the 3500 in say a 2005 Malibu is different, and if it is different, will it go into a 3400? I would assume that since the 3400 was rated at 175hp and the 3500 was rated at 200hp that the camshafts where different. I didn't want to go to crazy with the setup, but if i went with a topend swap i am sure a new camshaft would help that top end work better. I used to work at dealership and had access to all this but i dont work there anymore. Any help would be greatly appreciated.

[rluck9277]

actually one more question, with a 3500 top end swap, will i be able to use my stock injectors and fuel rail?

[rluck9277]

ok, i found out just now that an 05 3500 uses the same camshaft as a 3100/3400 (part # 12567117), does anybody now the specs of the stock cam? also if anybody wants a good website to get part numbers from, go to

http://www.pqparts.com/gmmc/default.asp?RND=452820061024274

its an online GM parts catalog from Jim Bradley Pontiac in Ann Arobr, MI. I have been trying to figure something out but am kinda confused, does the 3500 heads on a 3400 raise or lower the compression ratio? I was under the assumption that a 3500 head has a smaller combustion chamber then a 3400 head which would lower compression ratio, but then i thought i read on here somewhere that the 3500 heads lowered the compression ratio, if these heads lower the compression they would be good for turbo or supercharged applications, and i don't plan on doing either, anybody know for sure?

[bszopi]

Its not fully up-to-date, but here is the cam info:

http://60degreev6.com/showthread.php?t=16566

3500 heads have a larger combustion chamber and will lower the CR of a 3400 to ~9.1.

GMPartsDirect also has an online parts catalog for PN research.

[gectek]

ok so if the 3550 heads lower CR that much, then how can they improve performance that much?

[bszopi]

Allow more and better flow into the combustion chamber and have a better chamber/quench design. The CR change really isn't that significant.

[rluck9277]

if i did a 3500 top end swap do i use my stock injectors and fuel rail? how much power is this swap wurth? I have a tuned PCM, cold air intake, MSD igintion, and dynomax muffler, when i do the motor i plan on getting some s&s headers

[onefastV6]

With the 3500 swap you use your current fuel rail.

[alerored04]

im not too sure if the 3400 headers will bolt up to 3500 heads. Anyone got input on that?

[onefastV6]

im not too sure if the 3400 headers will bolt up to 3500 heads. Anyone got input on that?

I am running them on my 3500 heads now.

They fit just fine.

[alerored04]

oh cool. Wasnt sure if the exhaust ports were the same.

[onefastV6]

oh cool. Wasnt sure if the exhaust ports were the same.

Here is a pic of my front TOG header with the 3500 gasket layed over it.

[torq455]

I know the CR of the 3500 is 9.8:1. So they must use different pistons to gain the CR. They also redesigned the exhaust maniflolds as well. Much better flow.

[Scott_68B]

With the 3500 swap you use your current fuel rail.

Why not use the stock 3500 fuel rail? Just curious if there is an issue with it?

-- Scott

[bszopi]

Its a returnless setup, so there would have to be modifications made to the entire fuel system.