LT1 Head info

Hi guys, my wife has a 95 firebird formula. Last spring she decided it was a good idea to drive it with it hot until it quit running. The engine already had low oil pressure and I knew it had some problems. I purchased a 95 police interceptor engine so I can drop it in the car and rebuild her original engine. My question is, how much different are the cast police interceptor heads compared to the aluminum LT1 heads? I'm guessing her heads will be warped or cracked worse case scenario. And I figure I will be better off buying some after market heads when I rebuild her engine because she would like to start drag racing it while we are at the track. So I guess, what heads work the best for a tight budget on these engines?

[ThreeHonks]

used stock castings can be had for approx. $200

you will be better having the stock castings ported than going to an aftermarket casting. It all depends on how fast you want to go. Some guys ahve run in the 9's with ported stock heads, naturally aspirated

[JoeliusZ28]

interceptor heads are iron. They flow better as they are based on the vortec design, but due to the heat conduction they cannot offer as much compression. Overall they perform about the same, but the downside is that they weigh 40 pounds more than the aluminum versions.

[ThreeHonks]

please do not cheap out and put the iron heads you have in an fbody

[JoeliusZ28]

please do not cheap out and put the iron heads you have in an fbody

noticing that its his wife's car, which means its probably a stock setup... i think the difference would be negligible.

[prorac1]

Just paint the heads silver and all will be well, lol. Eric L

[JoeliusZ28]

[meissen]

Like Joel and Ryan are both saying - right now iron heads should be fine while you rebuild the other motor. For the drag racing setup a good stock heads ported would do you well. You don't have to go to Lloyd Elliot or Advanced Induction as there are a handful of great porters here in MI that are local.

[ThreeHonks]

sorry, read the original post worng. go ahead and use the iron heads for now (jsut to get the car running) but dont expect the same performance out of them as the f body heads (Aluminum)

[JoeliusZ28]

sorry, read the original post worng. go ahead and use the iron heads for now (jsut to get the car running) but dont expect the same performance out of them as the f body heads (Aluminum)

actually because of their flow advantage I have seen them perform quite comparably. Some even claim 1/4 mile gains from them. But in all honestly Im betting it is just fabricated information from some dumbo trying to cover up an idiot move. I certainly wouldn't risk the 40 pounds extra trying such a thing.

But that said, the LT1 could have had more potential if GM had been smart enough to make the aluminum LT1 casting the same as the vortecs. Unfortunately no such casting was ever created.

[ThreeHonks]

actually because of their flow advantage I have seen them perform quite comparably. Some even claim 1/4 mile gains from them. But in all honestly Im betting it is just fabricated information from some dumbo trying to cover up an idiot move. I certainly wouldn't risk the 40 pounds extra trying such a thing.

But that said, the LT1 could have had more potential if GM had been smart enough to make the aluminum LT1 casting the same as the vortecs. Unfortunately no such casting was ever created.

there is NO way that they get a performance gain. They have bigger chambers so they kill compression. They flow about the same, but I think what you are getting at is that they have a lot of meat on them for porting

[JoeliusZ28]

there is NO way that they get a performance gain. They have bigger chambers so they kill compression. They flow about the same, but I think what you are getting at is that they have a lot of meat on them for porting

They do not flow the same. The iron heads are based on the vortec heads/ports which do flow better.

http://www.fierolt1.com/lt1_lt4_headflow.htm

[Bad_Z28]

Great website, thanks!

[prorac1]

I can also testify to this. The iron heads do indeed flow beter. But.....but, they cost more to port because the cast iron is harder and takes more bits, sanding disks and time. You cant run as much compression because they are cast iron, and IIRC the combustion chamber is bigger effectively droping the compression on a stock F body lt1 short block. All that being said, they do flow very well, but I would stick with aluminum..................or just paint them silver and after a while you will start BELIEVING they are aluminum, and you will never notice the performance differance one way or the other, lol. Eric L

[ThreeHonks]

They do not flow the same. The iron heads are based on the vortec heads/ports which do flow better.

http://www.fierolt1.com/lt1_lt4_headflow.htm

Im just arguing that you wont see a huge performance gain with them. Especially if you wan to make good power, these heads arent for you.