lt4 heads on my 94 lt1

[DRAGIN]

i am looking at putting LT4 heads #10239902 on my lt1 along with an LT4 intake is that part # correct for the LT4 heads is there any other part # for the LT4 heads? the intake and heads should go onto my LT1 and everything will bolt on as it was on the lt1 correct? any advice will be appreciated. thanks

[FTA1995]

Yes and no, IF i remember correctly you'll need to machine your intake to match the larger intake ports on the heads. Otherwise they will *basically* bolt up so long as all the valvetrain components are selected to operate together.

[Injuneer]

LT4 vs LT1 part #'s.

http://www.grandsportregistry.com/lt1vslt4.htm

Does not appear to match the number you posted for the heads. Are these supposed to be factory LT4 heads? Is the manifold supposed to be factory LT4? They stopped making the LT4 intake manifold several years ago, and the "LT4 Conversion Kit" now comes with an Edelbrock LT4 intake manifold (unfortunately, with reduced plenum volume, to get the hokie "air-gap" feature).

Yes, you can bolt a set of LT4 heads, with an LT4 intake directly to your LT1 block with no modifications. The LT1 block was used to build the LT4 engine, so its a non-issue. There is no such thing as an LT4 block. What you can't do, and what appears to be incorrectly mentioned above - you can not bolt an LT4 intake to LT1 heads, without machining either the LT1 heads or the LT4 intake. Its not a problem with the size of the ports. Its a problem with the tops of the outside of the LT4 intake runners being taller than the LT1 intake runners, and interfering with the valve cover rail on the LT1 heads. The LT4 heads have a raised valve cover rail, compared to the LT1 heads.

In fact, while LT4 heads have 0.100" taller intake ports, the LT4 intake has the same size ports as the LT1 head, and doesn't even match the LT4 heads. There's jut more metal at the top of the port, in case you want to match the LT4 head ports. If you want a good flowing set of LT4 heads, the LT4 intake requires significant porting by someone who knows what they are doing.

Now for the real question - WHY do you want to put LT4 heads on your engine? Stock casting LT4 heads flow about 15% more than stock casting LT1 heads.... look at the link I posted... 212 CFM for the LT1 heads, 240 CFM for the LT4 heads. If effect, you are looking at $1,600 for a set of LT4 heads and an LT4 intake, when for the same amount of money, you could have your stock LT1 heads ported to flow 270-280 CFM, and they will throw in a matching cam.

I run LT4 heads and intake, but I have about $3,500 into the heads and intake. That was done 9 years ago. There are now people who can port LT1 heads to flow close to what my LT4's flow, for about 2/3 of what I spent. I wouldn't buy another set of LT4's. There are better aftermarket heads available now.