I've got an iron head LT1. I read last night that they actually improved the iron head design in 94-96 over the aluminum design in 92-93 to flow 20% better...anyone ever heard that? I read it out of a guide to rebuilding LT1s in the section that differentiates parts from different years. If this is so, what could be the possible hp output using these heads...anyone ever seen a really powerful iron head LT1? What did they use and what kind of time did they pull?

 

20% flow better ? I don't think so, all of the lt1 have almost the same power rating, the only difference that you'll see is on the corvette, the power rating will be higher since the exaust system is much better and also because of the exaust manifold centerdrop style it uses.


Professional porting will increase the flow alot, you could even have over 700 lift if you have the cash to built a motor like that.

The only problem is with Lt1 and major hp, is that if you spin it higher then 8000 rpm you'll blow the optispark since it's a pretty delicate system.

 

The iron heads do flow more than the alum, as cast, and i believe also when fully ported, but it still doesnt make up for the heat dissipation loss going from alum to iron to make it worth the change, the impalas had less hp mainly due to the camshaft.

 

So it wouldnt be worth it, especially for someone with a tight budget, to swap to aluminum heads when i could spend the money instead on porting the iron ones?

 

You can get the aluminum heads pretty cheap. I paid $250 for a set of 30K mile heads, complete with rockers. You'll get higher compression and weight savings with them also.

 

The iron heads flow like 230 cfm at .500 vs 216cfm of the aluminum ones.
The opti isn't the problem with running a motor to 8k. The computer will shut the motor down at 7k even if you eliminate the rev limiter. Ask me how I know.
You don't need to spin an lt1 over 6400 to make good power. Mine made max power at 6200 on the dyno.
Kory

 

I just finished taking the wiring harness off the motor i bought, most of it is there, but it stops at the firwall, i dont hve whatever comes before it....does alot come before it...or just the computer? And can u buy replacement connectors?