suburban conversion from 1/2 to 3/4 ton

[gnmas]

I'm looking to convert my 72 big block 1/2 ton suburban for towing an enclosed car trailer. I have a 72 3/4 ton pickup with leaf springs as a donor truck. Would it be better to use the leaf spring setup from the pickup or can i get away with using the coil setup? i will be towing approx 7000 lbs. My buddy wants to swap complete frames, but I want to avoid that if possible. He says the 3/4 ton chassis is beefier.