I?m starting what I think will be a 3 year build, mainly due to the cost. I have a 1967 GMC C20 Fleetside that has a running 305 V-6 and a 2 spd powerglide transmission, it all works but will need complete rebuild. My Plans for the truck is to do a complete off frame restoration and keep as much of it as I can stock on outside and to make it a safe and comfortable puller for a travel trailer and an everyday driver with some git up and go. My dilemma is to keep the 305 V-6 which is fairly rare and that I know nothing about its performance or to swap it with a 454 BBC and TH400 I have from a 1989 GMC rust bucket. This motor and transmission also run but will need rebuilt.
The 305's were notoriously under powered. I was unaware they were considered rare. That 454 will drink gas, but, I'm sure you are aware of that. Many guys these days are swapping in GM LS engines, myself included. Lots of horsepower and good economy in the same package. I believe those engines were only rated around 120 HP(?). And 200 ft.lb. torque, or somewhere near that(?). My uncle had one he drove to work for years and I remember it used alot of oil. Of course it was just plain run out.
