I have tried multiple silverado and sierra forums and can not get an answer so I thought I would just go for it.
I got an 87 silverado it had stock a 305 blew it up. Replaced the 87 305 with an 84 350. The 87 motor was fuel injected. The 84 came out of a carbed sierra. The guy used the carb heads and got the intake manifold to somewhat seal on the carb heads. The 84 is old and I ended up paying 50 bucks for a 1970 350. It has been bored .030 over hot tanked and getting new gaskets pistons camshaft (rv) and bearings. When I get the short block built I want to have the heads rebuilt. I don't want to buy an extra set of fuel injected heads. Does anyone know of an intake manifold that will go from carb heads to a fuel injection throttle body?
The problem that you're running into probably has to do with the changed intake bolt angles in the later SBCs versus the old style. Holley (and there might be others, too) makes a TBI to square-bore adapter that lets you put a TBI unit on top of any square bore intake. I don't know if there are any "made for TBI" intakes with the old bolt angles.
Exactly. You mount a square (or spread) bore intake to the heads, mount the plate to the intake, and then mount the throttle body to the plate. Any old random dual plane intake should work just fine. I had good luck with a Performer RPM on my old 3rd generation Camaro.