Went to order the stuff for my progressive carb and I need to know the bore size for the adapter. It says a small log is 1.5" and a large log is 1.75". The guy at Classic Inlines says he thinks it needs a 1.75, but he also thinks I will have no clearance issues after the conversion. I know a 250ci is considered a small block, but what about the log. I am not sure what makes the log small or large. Want to make sure before I hit the order button. Also I have always heard that there will be clearance issues when you convert to a 2BBL on a inline. I am thinking of ordering a 1 7/8" filter for this reason. I really like the 2 1/2" better. Anyone know the answer about how much clearance I will have?
'77 and later 250's had the larger valves 1.75" vs 1.649". The hex log is 1420 cc and the round log is 1345cc. You can tell the year by the first 2 digits on the log The 250 block is 1.66" taller than the small block 6 (144/170/200). The 240/300 are big block.
