I need some information on swappping out a frame. My car is a 73 , 4 speed. I have found a real nice (local too) 75, automatic frame.

I realize there is a difference in the #2 crossmember, the bracket for the clutch and possiblly the rear crossmember.

I can transfer the clutch bracket, but I am not sure about the #2 crossmember. I understand the 4 speed crossmember is welded and the auto one is bolted.

My main question is is there a way to modify the auto crossmember to work with the 4 speed or do I need to replace it with a welded in 4 speed crossmember.

If there are any other things that must be done I would like to know that too.

I would really like not to hack up my original 4 speed frame. I have seen prices of about $345 dollars for a replacement 4 speed crossmember so I would like to modify that auto crossmember to work with a 4 speed, if possible. Also this car is being done to be a driver and originality is not too important to me.

Thanks
Mark

 

Cross member is no sweat, almost direct swap, the mods are really easy....

 

Is the difference in the 4spd crossmember and the auto right in the center where the mount goes?

Can the auto member be modified to work with a 4speed?

I got http://www.71corvette.com/frames.html , that is pretty useful, good info.

Mark

 

Mark - the difference in the crossmember in the automatic is removable and the 4 speed if fixed. I converted my 78 from an auto to a 4 speed and just used a Hurst shifter instead of the stock shifter. This eliminated the need for the stock mounting bracket on the crossmember.

I think - as stated before - the biggest issue is the rear. You have chrome bumpers and the 75 has the "impact absorbing bumpers". I do think you can modify it to work and I am sure it has been done before

Also, there is a CF member who makes a fantastic bolt on bracket for the frame where you mount the Z-Bar. I think he goes by V8Ranger. I will see if I can find the post and add it. Much sturdier piece than anything stock or aftermarket.

V8Ranger Bracket Here

Good luck.

John

 

Not sure but I think the rear part of the 75 frame is different. I believe it has to do with the 75 rear bumper being for the federal 5mph crash standard. Just something for yo to check out.

 

Well, I didn't know about a bracket on the crossmember for the shifter, but my car already has a Hurst in it so I guess that's not a issue.

So anyway it sounds like I will be in pretty good shape,with some fairly minor modifications.

I actually had my choice of a 75 auto frame or a 75 4 speed frame, but the auto frame looks to be in much better shape than the 4speed one, with just some surface rust. The 4 speed frame has some deep scaley type rust and is not near as nice as the auto one.

My original frame has some rot in front of the left rear wheel. I figure there must be more that I can't see also.

My plan is to fit the engine /tranny in the new frame and do whatever mods to the brackets/rear crossmember that are needed. I will then take it to the blaster and get it cleaned. I will then bring it back and treat the interior of the frame and paint it and go from there.

I have two bays to work in so I will just remove components from the original frame, restore/replace them and install them in the new frame one, by one until it's done.

So armed with this information I will forge ahead and begin this restoration.

This whole Corvette thing is real new to me and I am having to educate myself as I go. I have been doing Mustangs for years and this will be the first car I have done with a frame that you can take the body off of. I expect the quality/results of the finished product to be better with the easy access to all the stuff. It will be fun once I dive in and get it all apart.

Thanks for the good information!

mark

 

I just contacted V8ranger for one of his Zbar brackets, that is much better than the stocker, thanks!