My 1992 RS 305 TBI Distributor Hole ID measures 1.500 inches? Was there a change for distributor hole ID? What the HECK! dave w

Are you asking if the hole is too big for the dizzy? If so the hole is gonna be bigger.

I'm doing a tbi conversion, the donor vehicle was a 1992 rs camaro. I did not get the distributor from the 92 rs. I thought all sbc distributor holes were 1.250 ID"? I guess I need a distributor from a 92 rs?

dave w

The 'whale' style Caprices used a distributor with a larger hole/flange diameter. The reason is for R&R of the distributor which is located partly under the cowling at the base of the windshield. With the larger opening in the manifold the distributor can be tipped over further.

RBob.

I think I figured it out. I took my caliper to the junk yard. Most factory SBC intake manifold distributor holes are about 1 3/8" or 1.375" diameter. Most factory SBC HEI distributors are 1 1/4" or 1.250" diameter. The distributor is centered / aligned by the block for the camshaft / distributor gear.

Maybe the factory engineers figured an intakes could be assembled to the engine with some large variations (front / back / left / right) because the intake mounting bolt holes are larger than 3/8" diameter. I feel so lucky to have found an intake with a distributor hole 1/8" or 0.125" larger diameter than most factory intakes. That's not what I would call quality control?

dave w