tbucketnut
October 22nd, 2022, 04:42 PM
Interesting problem I have with assembling my 305 for my GMC.
First off I was unable to use the original 305 in my 64 1000 wideside. I made a short trip down to Oregon and bought a used 305. I had this block cleaned mag'd and bored and honed to fit my pistons. At this point I had accumulated over the past two years, new pistons, main and rod bearings, cam and bearings , new timing gears and chain, and had the heads gone through with hardened exhaust seats.
I do all my own engine assembly and noticed right a way the .020 under main bears were loose in the webs and main caps -what the ****. Through a little bit of digging, I learned that blocks produced in 1973 and 74 had different housing bores for the main albeit the same journal sizes. It takes a 5061M main bearing set instead of a 4067M like 60-72 engines have.
Rod bearings are the same.
Did notice the rods in this 74 305C engine are a lot beefier than the 305E engine.
Cheers fellow friends,
Steve
First off I was unable to use the original 305 in my 64 1000 wideside. I made a short trip down to Oregon and bought a used 305. I had this block cleaned mag'd and bored and honed to fit my pistons. At this point I had accumulated over the past two years, new pistons, main and rod bearings, cam and bearings , new timing gears and chain, and had the heads gone through with hardened exhaust seats.
I do all my own engine assembly and noticed right a way the .020 under main bears were loose in the webs and main caps -what the ****. Through a little bit of digging, I learned that blocks produced in 1973 and 74 had different housing bores for the main albeit the same journal sizes. It takes a 5061M main bearing set instead of a 4067M like 60-72 engines have.
Rod bearings are the same.
Did notice the rods in this 74 305C engine are a lot beefier than the 305E engine.
Cheers fellow friends,
Steve