Gear placement: 302 ford dimensions from bottom of distributor housing mounting flange to bottom of gear for all 289/302 distributors: 4.031"-4.038"
Gear placement: Y-BLOCK - from bottom of distributor housing mounting flange to bottom of gear for all y-block distributors: 4.991"-4.996".
This measurement can only be taken accurately with the distributor shaft pushed to the bottom and some type of straight edge clamped to the bottom of the distributor gear. Use a high-quality digital caliper.
A 302 distributor (SBF) housing fits the Y-BLOCK without a problem, but the shaft is .958" too short. If an attempt is made, the gear will not fit tightly. The Y-BLOCK shaft can be used to replace the 302 shaft if it is in good shape. The gear must run on the pad in the block with .008"to .012" end play or it will not live very long.