Simple SBC question

Are all Gen I blocks the same external dimensions? I'm putting an early 60's 283 in my car and mocking it up with an empty 350 block from the mid 70's while I do the work to the 283. Don't want to sound dumb but don't want to set everything thing up with this block and the other not fit.

 

Early 60's to 70's 350 blocks and all years forward are the same. Early pre 67 (?) heads had no threaded holes front and back for accessories.

Basically if you have the 3 side engine mount bolt holes surrounding the freeze plug you are good to swap away.

 

Yes.

 

Right on, that's all I needed to know.

Thanks for the help!