I measured 4 distributors all came up 1.250. I measures 3 intakes (small block but should be same) 1.375. that makes your clearance .0625 per side or .125 side to side. Time the distributor is all the way down in the engine it has other bores it lines up in there is very little play if any at all. If you are all the way down I'd check the bores in the block as the intake realy isn't what it matches up to.