I've got 72 carbs bolting onto a 73 intake manifold with the
73 Carb Insulator Blocks. I can barely get the nuts on the
studs because the insulator blocks are "too fat". Are the 72
or 70-71 insulator blocks "thinner"?
if you take a little trip to the hardware store ie lowes home depot or the like you get get longer studs. and you wouldnt want smaller insulator blocks from what i here, from people like norm is that doubling your blocks helps with the torque curve.
I have the thin insulator blocks on my SU conversion with the 74 manifold still in place. I believe the thick insulators with the flat tops were to help with the vapor lock problem that flat tops are prone to. The SU conversion is a much more compact installation, and you should get much better air flow around those carbs as opposed to the outsized flat tops. Maybe someone on this forum will sell you a set of thin blocks for the SU set up. I am using a 71 air filter, as I have seen postings that you get a much better air flow through the carbs due to the air
horns installed withing the filter housing. Good luck.