Im not sure if this thread belongs here but if not then please move it to the appropriate catagory. I have a 355 2-bolt main with flat top pistons approx 9:1 with sucky 882 heads and 750 carb on a airgap intake and 278 cam. I'd like 350 to 375 hp but cant reach there with these 882's. I have a chance to buy some other heads and just need to know if this is a good buy or not for my application. Casting 3947041 completely rebuilt with 2.02/1.60's for $650.00, but some charts say that the downer is that the water jacket is pretty close to the springs. Other than that its a good head for 300-350hp. Has anyone has experience with these heads? Thanks.

Mark

 

I have had two sets of these, one is on a 4 wheel drive and the other we put on a 350 that went into a carbed 91 RS camaro of my freinds. The RS camaros were ported pretty good by me, we also enlarged the spring seat (they didnt make them deeper as far as I know) to fit in 1.46 wide springs. They are very nice heads and the car runs very very strong, I didnt get a chance to flow them, but I would say they could support 350 rwhp pretty easily.

 

is the price fair? Non-ported but completely resurfaced and rebuilt. I just see heads at swaps for 400-600 that need work.

 

Have you considered Vortec heads? Sure you'll need a Vortec #7516 Air Gap manifold, but you should be able to sell your #7501 Air Gap for a decent price.

Vortec's flow better than almost all ported 041's. I believe their stock flow will support 350 rwhp+. You probably want to mill them to get a little more compression.

My $.02

 

Vortec heads are always cheaper than other high hp heads. I figured this meant there was something wrong with Vortec's.
I know my intake would need the change, but will all my assec. holes match and will my headers match?

 

All things will fit except the intake and intake gasket basically and you'd want new intake bolts too also I guess. Vortec's blow ANY production 23 degree head. The LT4 might be better but I'm guessing it isn't as far as low lift flow numbers are concerned. They can easily support 400+hp with the right parts. Goodluck!

 

B-body LT1 heads. D-port & nice flow numbers... too bad their iron though.

 

Vortecs are pretty close to these iron anchors in port shape/flow, but fit the older SBC Mark seems to be using.

Vortecs are (relatively) cheap because millions (?) have been made for the 350 truck engines which just peceeded the LS engines.

One of the mags did a whole series of engine build-ups starting with a basic 9:1 350 production short block. One iteration has Vortecs and a AirGap, if I remember correctly. I'll look for it.

 

Best magazine write up I've seen so far involving Vortec heads was a 365 cube limit pitting Chevy vs. Mopar vs. Ford. Pump gas only, no port work. Combo looked like this:

SDPC Modified for extra lift Vortec heads
242/252 roughly .530 lift 106 lobe sep.
10.4:1 comp.
1-5/8" long tubes
RPM Air Gap Intake out of the box
Mighty Demon carb

They ended up with 430hp @ 5800-6000 and around 4500TQ. The engine made 5" of Vac and loped like a beast. I got a feeling with some head work and a Super Vic intake they could have seen closer to 500hp which would be fun in a light car and would still be "budget" minded.

 

Thanks!!! Im rebuilding my 79 z-28 that's been on blocks for 10 years since high school. I have my interior completely restored. My motor's is rebuilt but I'm looking for more hp now. I'll start looking at the swap meets for some vortec's... and hopefully with work already done on them.

one more question though... is there such a huge difference in power between 1.94/1.50's and 2.02/1.60's?

Thanks for the info guys, I appreciate it.

Mark

 

Which vortec heads should I be looking for? I have a casting number chart but there are LT1, L89, etc. Which series heads should I go with for my 74' block?