Floor Pan Questions

You may be on to something here. I measured both my 66 cars and both have track bolt measurements of 14". The floorpan holes also have that same width. I also measured a set of buckets I have from a 65 Cuda and the track bolt spacing on those is close to 18".

Now, here's the ironic part and maybe a clue to the extra holes. If you measure from the inner holes to the very outside holes, that measures roughly 18". I think that the outer holes are for 65 and earlier cars with bench or bucket, and in 66 you may be right that the track mount spacing may have changed for buckets but the outer holes are still punched and plugged in case it's a bench seat car!!

Just a guess, and glad you brought that up, maybe it's a mystery solved!! "And I would've gotten away with it to if it wern't for those meddling kids"!! Rooby Roooo!! Geof