Technical 1948 chevy sytlemaster frame question

Hoping someone can shed some light on this. More of a truck guy so this is a bit out of my realm.

I see plenty of guys doing front clips or aftermarket IFS on these cars so figured theres no problem in doing so. however, I am looking at a car for sale and the owner says that when you step on it hard from a stop, the steering is a bit funky and it can get away from you. It was a good professional build, with a Camaro front end, 350, 700r, nova rear end. He said it probably needed softer springs up front.

I was good with that answer, with my lack of knowledge with these cars, until I spoke with my uncle who is redoing a 40 Pontiac and mentioned that he couldn't believe how weak the frame was structurally. Is the frame in the 48 similar and could this be causing the steering problems?

front springs too hard? weak original frame? what might be causing the steering issue?

thanks for your time.

 

Have a professional front end shop check it out.....

 

Take a real good look at where and how the Camaro subframe is mated to the stock frame, clean up the area thoroughly and inspect for any cracks, poke around with a big screwdriver on the stock frame to check for any areas where rust may have compromised the strength of the frame. If I remember right, this car has the "tophat" construction, basically a U-channel with a flat plate welded over the open side. Not unlike '54-'56 Ford front crossmembers, they are known for trapping moisture and rusting out from the inside.

 

...could be an alignment issue with the clip or rearend installed wrong (not square to chassis)

 

'40s GM cars do not have weak frames. Not by a long shot ....

 

First let me say I have several '40s GM cars and the frames are not weak, they are however built to flex The top hat design is made of thin metal so you need to be careful when welding on them. I prefer the bolt on front suspensions like Ron Meyer.
When sub framing with a Camaro type front end it is critical that the vehicle be on stands at the actual ride height you want in the finished product. Drop a plumb bob from the original axle centerline to the floor and mark it as a reference point. Drop a line from the rear axle center to the floor and mark it as well. Now check that the centerlines are square with each other and don't do anything else until they are.
With everything square you can now measure and decide where to cut the frames to join them. The axle center of the donor clip must be exactly over the mark you made from the original axle centerline.
When you finally have it lined up you must make sure the upper "A" arm is at the correct angle for the front suspension to work as the factory designed it. In the case of the Camaro you can place a level across the "A" arm and set it to 10# down in the rear. Recheck all of the dimensions and if it is correct then weld up the connection of the two frames.
I would suspect that the car in question has the angle off and there is not enough caster to keep it straight when the front end lifts during acceleration. If an alignment shop can get it in spec it will probably be OK but if not it will be expensive or impossible to fix.

 

I would have no problem welding on a sub frame or welding on a mustang II crossmember, I used a weld on Mustang II crossmember on the 42 Chevy I am building

 

I've owned and built several cars with subs. Never an issue like that. Like the others said, have it looked at by someone in the know. I agree that is is likely a bad alignment, or improper installation of the sub. Possible worn out parts, too, I guess!