I'm hoping to upgrade my whole top-end at the end of this year, providing I am employed during the next semester in college(probably, this year I couldn't find anything)

This is what I'm looking at, my emphasis is on torque, as that is what the cam-shaft is set up for.

The heads I am looking at are GM's alluminum fast-burn heads. They are cheap, but very effective for the money. I am worried about the valve sizes. They are 2.00 intake, 1.55 exhaust, how much is this going to hurt my torque? Stock is 1.94 in, 1.50 out, I would prefer to find heads closer to that, but for the price, I think I may be able to settle.

I was going to do these heads when I put the motor together, but edelbrock was about three months slow getting their adaptor intake manifold done. For the runners, I am planning on Edelbrock's large tube runners, and the stock plenum, polished to a greater extent than the minor polishing I did when the motor was apart.

I am going to leave the stock throttle body, as it should flow more than enough, and is easy enough to change. If I feel the car is still suffocating, it would not be hard to install a 52 mm TB.

Any suggestions? Thanks. :)

 

You could port match the intake to the new heads. You could shave them heads,raise the compression and machine intake to match. Are those runners the siamesed openings or just larger tubes I thought the siamesed ones sacrificed some low end tq. for some upper rpm power. :cool: :smash:

 

If your emphasis is on torque, and you're sticking with the TPI, I would consider the Vortec cast iron heads over the fast burns or edelbrock's e-tec 170s if you want to stay aluminum. I think that the Fast Burns are too big for a TPI engine. Even wth a performance intake and high flow runners. The vortecs would be cheaper to buy, port, and set up with a good valve train and would perform better on your engine than the fast burns would. If you were going with a bigger engine(assuming you're still 350), and an LT1 or Mini Ram intake manifold, I would definately say go with the fast burns. If you read GMs propaganda about them, they say they made 500 horsepower with these heads at 5800 RPMs. 5800 is nothing for a short runner intake, but the TPI just can't get you there to maximize horse power. It will run there, but its best power should come in about 1000 below that. Plus putting a 64cc head on your L98 is only going to lower your compression. And GM doesn't recomend changing the dynamics of the chamber, which would happen with milling the heads.

Everybody has an opinion... and thats mine. :cheers:

Just out of curiosity, what are the specs on the cam you're running? And is Edelbrock building a TPI base to fit raised intake runner heads like the fast burns that you know of?
:seeya

 

Thanks for the suggestions. :) I don't want to put iron heads on my car, the compression is too high, I'd have to get a bigger combustion chamber on iron heads. As it sits, I have about 10.75:1 compression, with the 64 cc chambers, I'm figuring I'm going to see about 10:1.

Not that the idea hasn't crossed my mind to go Vortec, they are so cheap, and flow so much...but I can't handle the weight, nor the going back in time.

My cam is approximately(with 1.6 roller rockers) .485 int .498 ex. 214/220 duration, with a 112 degree lobe seperation. I have a full exhaust, headers, and everything, and the bottom end is built, the final piece of the recipe is to get some air into the engine. As you can see, the cam-shaft if focused on that TPI intake, and maximizing its biggest asset, torque.

I think I'm going to try to get some computer dyno's together with the Fast-Burn flow numbers and valve sizes and see how it looks. If I see 500 lbs of torque at the flywheel, I'd be happy, I'd sacrifice some of that for horsepower, but not much of it.

Edelbrock came out with a Vortec TPI base around October, it lowers the head-side ports or something, while retaining the stock location of the runner ports. The reason my car doesn't have aftermarket heads now is because they hadn't released the manifold when I put the motor together.

Thanks again for the suggestion, I'm definitely going to have to do a lot more research before I finally commit to a setup. :cheers:

 

Yeah, thats definately a torque cam. And you would have good enough compression to run the fast burns. I just think they're a mis-match for the TPI.

I agree with you on not wanting the weight and heat sink of the cast irons.

Good luck. :cheers: