? if any one could help me on a stock 1989 iroc 5.7 what heads could I buy and slap on with out having to do anything other then bolting them on and running. the bigest bang for the buck with out going threw the bottom end and changing the cam.

 

Edelbrock performers worked good for me.

 

There's a deal going on AFR's in the classifieds. Search for 1040 in the engine parts classifieds and you'll find it.

 

You know the part number by chance I found 4 different Edelbrock heads so far and all you did was bolt them on and run didn't have to change any thing?

 

Corvette Aluminum 113 heads for an L98 bolt right on. Only thing you have to change is the sparkplugs.

One question though, why on earth would you change the heads and not the cam? Our engines aren't limited by head flow, they are limited by the ridiculously puny cams that were installed in them for emissions. Forget seeing any noticeable benefit from the heads until you get a better cam in there.

-Levi

 

well right now I am running 13.2 in the 1/4 with little done 3:23 gears built 700r4 full manual revers shift pattern 2800 stall, edelbrock performer dual plane intake,HEI vacuum advance distributor running 10dergeas advance at idle and 32 advance at 5000 rpms, summit 750 double pumper street and strip carb, 160 thermostat, nitto drag tires, bbk power pulleys. no a/c or heat gutted that,hooker shorty headers with 2 1/2 inch y pipe that goes to 3 inch flow master 80 series muffler, no computer re wired every thing and I run 12.5 in the 1/4 with the NOS 125 shot system so over all its not bad i just wanted to do heads and see what that will get me. if i go with heads that bolt on and 1.6 rocker arms its about the same as having a mild cam i would increase the stock lift and the heads would flow better the stock heads flow like **** and there only good up to 4500 rpms after that they fall i was always told. Over all I think its not that bad just looking to try to get in the 11's with spray and mid 12's on motor If you where me what heads and cam would you go with? looking for easy install with out having to go threw the bottom end.

 

A lot of it has to do with your budget. I'll correct one fallacy though, the factory heads don't flow "that bad" and they can be ported to flow even better. Would they be a restriction on a 450 hp motor? Absolutely. Are they your limiting factor right now? Absolutely not. What is causing your motor to "fall flat" at 4500 rpm is the cam, not the heads. Would heads help, probably so, but you not alone. A cam swap by itself will net a large improvement, and a cam and head swap together would be a great improvement. Think of it that way. Heads alone are going to get you virtually nothing. In fact, a head that flows a lot more coupled with the very small factory cam could actually hurt performance, particularly torque and throttle response.

1. If you have a healthy budget:
-Cam along the lines of a XR264 from Comp Cams, or an LT4 Hot Cam from GM Performance. Hydraulic Roller, great pattern for a 350. Stay away from extreme grinds, look for something in the duration and lift range of those two.
-AFR heads. Best out there in aluminum for a SBC. Stay with a smaller intake port, something like the 180cc head, and keep the combustion chamber as small as possible. With a 64cc combustion chamber, you will keep the same compression ratio you have now. You'll need at least that with an aluminum head, as it requires a higher compression ratio than a cast iron head for the same performance.

Option 2: Budget:
-Get a used roller cam. Scourge the forums for guys who've changed directions on their own projects. Shoot for the same range I listed above.
-Port the heads you've got. This has been proven to work great
-If you want aluminum, grab the L98 Corvette head. Look for the D-Port exhaust, they flow the best (this is the same head as the ZZ4 crate motor has)
-Maybe your best option, get Vortec heads. You'll have to have the valve guides worked a bit for the higher lift, but you'd have to do that with your factory heads anyways. These things flow great. Their only drawback is that they require a vortec specific intake.

Speaking of intakes, look at something along the lines of the Performer RPM. That will help move your power band up just a bit too. I've heard great things about the RPM air gap. I'm also very pleased with the Weiand Street Warrior on my build.

The rest of your setup looks spot on. You're running pretty much everything the same as mine, save for the nitrous and the carb. I run a Q-jet with a JEGS HEI mechanical/vacuum advance distributor (14 degrees intital, 35 degrees total), shorty headers, into a 3" y and an edelbrock cat-back exhaust. You're one drawback may be the 2.5" y-pipe. It could be choking you a bit, but it shouldn't be too noticable.

Anyways, that's just my advice, and it's probably worth what you payed for it.

-Levi

 

Ok hey thanx for taking the time defiantly gave me a lot to think about i will let you know what the out come is and thanx again


Rob