I was just putting on a modified LT-1 intake manifold that I bought some months ago and I'm encountering some unexpected issues. The previous owner took it off his 92 "F" body, but he had 85 heads on it (most likely cast iron) but all the center bolt holes seem to be drilled for the 86+ cast iron heads at the 87 degree angle, but the other 8 don't seem to line up? I can get maybe one or two bolts in the holes, but they do not fully seat on the intake in the recesses on the manifold. This manifold was supposed to have been modified by LT1Intake, but as his site is gone I can't even ask him, and the person I bought it from does not seem to answer emails...can anybody help at all??

 

http://www.popularhotrodding.com/tec...ls1/index.html

This link is to a swap. It has some good info.

Your bolt holes need to be drilled to match the heads, and you need the correct length bolts it sounds like to me. Google the swap, and read everything you can.

 

Use a SBC intake gasket to check that the holes are even close. If they are you may get by with enlarging or slightly elongating them

Even if the manifold was drilled for the older heads, the remaining bolts should still line up. Hopefully you didnt just get a stock intake with the dist hole cut

Other stuff to look for

Make sure the EGR port is completely covered on the bottom of the intake. Material needs to be added

Make sure the front/rear water crossovers have material added or you will constantly leak coolant

 

Thanks for the replys guys any and all information helps.

Powerslave...as it turns out I found that article some time back (been researching this swap since last August (09)) and even bought the back issue.

Pocket...when I first got the manifold, checking the bolt hole alignment with another intake gasket confirmed the holes, while not exactly centered, were in the right position, here in lies the real problem. When I put the intake on the engine and began putting in the bolts, I found the 4 center ones would not allow even one bolt to start. After seeing much discussion on "elongating" the bolt holes I did not think to much of it so I tried the others and found only two or three would actually go into the heads, and with those the "spot surface" of the manifold where the bolt sat was way off, so the head of the bolt that did at least "start" in the head was not flush with the cutout.

At this point I stopped because I found that trying to elongate the bolt hole in the manifold with a drill was not going to work. I was going to then use my air die grinder, but did not have a bit to fit the job, so rather then ruin it, I thought I'd look for more "install advice" here.