[YENKO DEUCE REGISTRY]

Will;
The two small holes in the crossmember indicate a small block, regardless of trans type, (the car is definitely a manual shift car). If a prior owner installed an a/t trans, I would assume that it was a TH350 since a TH400 requires a completely different crossmember (more of a 'tubular' design). Once you get the broadcast sheet out of the seat, 1st make sure that the body number on the sheet matches the last six digits of the body number on the trim tag. I have seen several instances where the wrong broadcast sheet is found in the original seats, although this probably indicates that the line worker was following the codes on the sheet taped to the firewall, installed the correct seat type into the car, but did not select the seat specific identified to that particular car.

Then look at the various option boxes, it will say L34 for 396/350hp, or L78 for the 375hp version if it was a big block. If the car was a small block, there will most likely be no engine code designation on the sheet. If the car was a console car, there will be a code on the sheet (for the tunnel piercings), you should definitely have the B80, B84, B90, (I think), and especially Z26 for the Super Sport option, A51 for the buckets, M20 for the 4speed, N10 for the dual exhaust, and probably some more since the car seems to be nicely optioned. Let us know the codes, and we'll let you know what they mean.

Even if it turns out not to be a big block car, it would be a nice car when done right.