Need ideas on ls swap.

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I have a 70 lwb c-10 that im going to put a 5.3 4l80 into,
Would it be better to just swap my cab and body over to the newer frame or would it be better to use the 70 frame and just get all the mounts needed to swap it over? The donor truck is a 2000 long bed reg cab. Its a 3/4 ton which is why im thinking it would be better to just pull the motor and swap it. What do you guys think?????