I'm converting from TBI to carb. I read a lot about people using RPM Air Gap manifolds and others that have a differant bolt patern than my '89 cast iron heads. I understand that the center four intake bolts are at a differant angle. Can I still use something like the RPM Air Gap that is engineered for pre 86 SBC heads? Hood clearance is not an issue, but what about the bolt pattern?

 

you can use pre-87 intakes on post-87 heads. You will have to elongate the 4 center holes with a dremel or die grinder, and fabricate some angled washers. OR you can have a shop mod the intake.

It's a little bit of a PITA, but it works just fine.

Also, try to trim down the sig a bit. At least to something a little less than 4x the length of your post.

 

Sounds like more trouble than it's worth. Have you heard anything about the Holley street avenger made for '87 and up heads. It is a high rise dual plane design. When I check Holley's website for the street aveng manifold it showed a weiand stealth. Are those two the same thing?