In the Task Force era GMC and Chevy 1/2 ton trucks, are the front crossmembers the same?

I want to mount a period correct 283-V8 in my GMC chassis using the original type chevy front mounts, but then it occurred to me that the GMC motors were longer than the chevy and that the front crossmember may be different. I'm pretty sure that was the case on earlier year trucks anyway. Does anybody know for sure about the TF trucks?

Red58? You're very knowledgeable, any idea?

I have a '58 Chevy and a '58 GMC, but unfortunately they are not both in the same location so I can't compare them side by side.

Thanks.

Mike
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1958 Chevy 3200 Fleetside
1958 GMC 100 Wideside
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