Originally posted by Grigg:
I suspect the radiator support will bolt to the frame the same because the fenders bolt to it
Its not that simple. The radiator on the GMC is further forward because of the longer motor. If you look at the front crossmember the Chevy and GMC are quite a bit different.
I do not think the radiator support from a GMC will simply bolt to the Chevy frame in the proper location.
Not to say it can't be done, but understand going in that either you will be swapping the front crossmember, or doing some other adapting to make it work.
This photo is a Chevy front crossmember with part of the motor mount still in place.
Chevy Crossmember And this is a GMC front crossmember. Note how the radiator mount postion is lower and pushed further forward.
GMC Crossmember The front crossmember is probably the most significant difference between a Chevy and GMC frame. Most anything changes more year to year than Chevy to GMC.
The rear mount difference is going to impact you a little differently. The hasp type rear mount of the later years should be easy to adapt since it simply bolts to the frame. The challenge will be getting the bolt holes in exactly the right place and with care that should not be a big deal. I'm not sure if the 3/4-ton rear mount is different than the 1/2-ton, that's where the rear mount may present more trouble.
