duramax swap

[k20chevy 454]

okay guys im seriously thinking about swapping a duramax into my 78 k-20,okay currently i got a 78 k-20 frame with a crew cab body going onto it with 1 tons and 42's,now i got a 454,sm 465,np203
1.does anyone know how much the duramax wieghts compared to a 454
2.will i need to fully box the frame?and can someone show me pics of a duramax engine mount
3.if i do this i will be buying a wrecked d-max truck to pull everything aut of
4.did duramax ever come standard?or only automatic,if only auto is the 5 or 6 speed better?
thanks guys i really want to do this swap,but just wanted to c if it was worth it

[billywilly92]

Im guessing the d-max weighs a lot more than a 454. Also the frame will have to be boxed to handle the power. But I think the electronics are the hardest thing to set up or at least I think thats what I read somewhere on here but don't quote me on that.

[iallen4190]

some have a manual 6 speed tranny (01-04 IIRC). The auto 6 speeds are a little better but they only come in 06 and up so they will be more $