Help! Need a 305 for a 1986

57ringo · October 10, 2003

My nephew knocked a rod out of his 1986 c1500 with a 305. What other engines are a direct replacement? I'm going to change it for him and don't want to run into and more problems than is normal. I heard since this is the first year for the one piece rear seal and last of the carburated engines, it is a little rare. He wanted a 350 but I was told something was different with the exhaust manifolds or how they bolted on( one has 7 bolts). Can anyone help me out here?

mjsmith1223 · October 11, 2003

On my truck ('86 GMC C1500) the previous owner never changed the oil or added any so the stock 305 seized. He then sold it. We put a mid-70's 350 in it that came out of a Suburban. Bolted right up to the tranny, and no need for the all the electronic connections anymore. We had to recycle the power steering pump from the 305 because the one on the 350 didn't fit right in the space. The exhaust was an issue. The manifolds that came on the 350 were used but I seem to remember some issues with making the Y-pipe fit. Apparently the issues were solved, because all is well on the exhaust system now. We also were able to recycle the engine mounts, fan, fan clutch, upper and lower hoses and radiator.

You should be able to swap to a 350 no problem. Might want to prowl the bone yard to find some exhaust manifolds if the engine you pick up doesn't have any - or just put headers on it A brand new Goodwrench crate 350 seems to run $1200-1300. A used 350 will be less. I think we paid about $500 for the one we used.