1952 Buick frame swap

I have a 1952 buick special that I would like to swap over to a 1978 olds 98 frame . should I cut out the firewall and fit it that way so that I would have the brake pedal structure. Any thoughts?

 

First, welcome to the HAMB from Illinois.
As to your question, frame swaps using a 'late model' chassis are usually not considered a traditional modification, so you may get some negative responses to your question.

 

Welcome @shade tree. Foregoing the fact that we are a traditional forum, I have to ask why you would want to go thru all of this work to change out that frame? Where is the benefit to that or is your frame in such terrible shape that it needs it?
I had a '51 that i saved from setting in a back yard for way too many years. Had trees growing up thru the bumpers spaces. We saved it, got it running and moving in the yard then passed it on to a younger fella that was going to do a custom out of it. He, in his enthusium at the moment, was going to to reframe it with a 76 Impala frame until he began to investigate that proposition further. A ton of work and reengineering just to get the advantage of more modern drive line and braking.
I would do further research and perhaps look at some of our traditional build threads from members like @rockable (49 Buick) or @BJR. You could also discuss your thoughts with one of our infamous Buick experts @Hnstray.
Good luck with your project. Be good to have you hang around but we traditional old farts have to follow the rules.