I'm not sure you can redrill an older intake to fit on new heads. I've got new aluminum heads that have both bolt patterns for old and new style intakes, and with my old tunnel ram installed I can still see two of the threaded holes for the new style intakes. If I can see them, then there's no metal there to redrill.

 

I am 100% certain you can redrill a new style intake to fit older heads.
I have personally done it. I redrilled the TPI off a 90's Camaro to fit a first gen
set off heads.

You oval the holes and use large washers. They go in at a different angle.

 

I can see how you could redrill a later Vortec style intake to fit old heads, but not drill an old intake to fit new heads. Just wont go that way.

 

Yes you can redrill the holes on an older style intake to match newer style (center valve cover bolt) heads, it's the two intake mount bolt holes in the middle on each side that needs to get re-angled. But a non-Vortec intake will not work/fit on Vortec heads, as the Vortec runners are taller and there isn't enough meat on an old style intake to seal the upper part of the gasket. New style heads and Vortec's are two different animals.

 

I agree that drilling out pre 87 intakes to fit 87+ heads isn't a good idea at all. I just know it's been done. I picked up a Edelbrock Performer RPM intake off Craigslist that had been drilled out. The holes are ovaled. Now I have to use a larger washer on those 4 bolts.

I brought it up because the original poster found an 87 motor out of a IROC Camaro. Then he'd have to find a 87+ carb intake to match up. I'm no expert on 3rd gens so I am assuming it has a fuel injected intake.

 

I still don't understand how you can drill out a hole when there's no material over it? I can clearly see the end hole on each end visable on my heads, so the old intake doesn't even cover the hole with metal that could be drilled?

I went out and took a pic of my intake and heads. You can see the one end hole completely exposed, and just see half of the other hole.:

 

I'll have to see if I can find a picture or if I have an archived article on the intake differences. The holes in question aren't the end ones. On the newer style heads and intake, only the two in the center, on both sides, mount straight up and down. The rest of the bolts are still angled like the old style manifold/heads are. Those center bolt holes on the manifold are the ones you would need to hog out to get the bolts in vertically, with using washers or a spacer under the bolts.

 

Thanks Chuck. Wonder what the other vertical holes are for on these heads I have?
Edit: I amswered my own question. Went to Summit and brought up a Vortec intake. Those holes are for the Vortec intake. Here's a view of the Vortec, it appears to use all the holes my head have:
http://www.summitracing.com/parts/SUM-226018/?rtype=10

 

Limey is correct and I don't think the block is set up for a manual fuel pump and they are externally balanced like the big blocks and 400's

 

The Profession Products intakes have a little adapter deal that slips into the middle holes, basically converting it to either style head. Pre and post 87.