Q's on subframe swap

[55metalmonkey]

55 GMC step-side shortbox (TF) & 72 Camaro sub frame with 350/ TH400 to be installed

I figured I should ask a few questions from this forums massive brain trust before I dig out the scalpel (sawsall) and cut my frame to do a camaro clip install. I’ve pretty much read the whole internet on the subject and checked out just about every possible way it has been done. I’m planning on using the whole clip and laying the bottom edge of the original frame on top of the sub frame, this should give me TONS of strength. BTW thanks to whoever posted the pics of the very nice silver painted one done this way on this forum, it made convincing the boss (wifie) that this was the best way to go with it.I’m planning on making a paralleling jig to make sure everything is perfectly square by using two long bars (1 per side) welded to wheel blanks and bolting them to the wheel mounting surfaces, I figure that if I make each side of the jig symmetrical to the other there is no possible way the clip would fit in place without being perfectly square, of course I’ll measure everything 1000 times before I start welding.

This brings me to a few questions:
1: From what I’ve read some people keep the wheel base at 114” and don’t have any issues while others have had problems with the bottom of the radiator rubbing or interfering with the steering box. Has anyone experienced this? Rad is an original style 4 core from CPP

2: Some people recommend adding 2” to the wheel base (i.e. 116”) which is more intended to center the front wheel better in the wheel opening but also they seem to avoid the possible issue in raised in question #1. I was planning a compromise between the two at 115” but am curious as to others opinions and experience with adding to the wheel base.

3: I’m also planning to do an axle over spring in the rear but haven’t been able to get any real info on how much of a C notch is needed to maintain clearance. It already has a camaro rear end and I’m not planning on hauling anything much heavier than the sister in-law (and even then she can take the bus IMO) so I’m wondering how much will give me good clearance and not be too much? BTW it will get boxed with ¼” steel also.

Thanks All