All 305 V6s are not created equal

[tbucketnut]

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

[AZKen]

Good info Steve. Don't forget to post a video of the first start up! You can go into business rebuilding GMC V6.

[tbucketnut]

I'll try and get a video up when the times comes.
If Somebody here needs a freshly ground and polished crank .020 undersize on the main journals and .020 undersize on the rod journals, with a set of almost impossible to find matching main bearings and a set of matching rod bearings. I will sell for my machining cost and bearing costs picked up in Washington State. This is ready to go for a 60- 72 block all cubic inches with 3.58" stroke.

Steve