1961 GMC V-6

[chevyguydan]

I'm going to look at a 61 GMC later this month and know very little about this V-6 cyl. Its backed by a 4 speed on a 3/4 ton long bed. I know about the 216's, the 235's, the 250's and the 292's Can anyone shed some light on this engine? durability, mileage, idiosyncricies, etc. The truck can be made run , ie it starts and moves, has brakes, but not licensed/inspected etc. To quote the owner, "it needs a tune-up". Hmmm, I'll take a compression reading if it sounds kinda funny. What kind of reading should I be looking for, my guess ia anything over 100 with no more than a 10% difference between highest and lowest.
Will a 250 bolt in place if this engine has major issues, or is the overhaul parts readily availible and reasonable?
Oh, BTW,
This place is nice!
Thanks in advance,
ChevyGuyDan

 

[78subgeorge]

The V6 was used in larger trucks, but GMC put them in pickups to distinguish their product from Chevy's. GMC also used Pontiac V8s for the same reason.

The engines were built in displacements of 305, 351, 401, & 478 CID. GMC even coupled two together as a V12! It had 2 distributors! Check a Motor's manual, but I think the displacement was stamped on the block in front of the right cylinder head. I would expect a pickup to have a 305 or maybe a 351

The V6 has the spark plugs on the intake side of the heads. It's very important to clean dirt & crud away from the plug areas before removing them. The PCV valve is screwed into an intake passage that's under the valve cover, so it's not visible with the valve cover in place. This means that a plugged PCV valve won't be obvious but sure could affect operation.

These are rugged heavy-duty engines with a lot of torque. They don't like a lot of RPM & fuel mileage isn't great. A Chevy 6 or 8 would give you better versatility, but if you want to pull a load, the V6 is great. I don't know about parts availability, as I haven't touched one in nearly 30 years.

Thanks for the 30 year trip down memory lane!

 

[grand79am]

Dan, that will be a 305, It has big ole pistons and would run strong. However, it is a costly rebuild. I would put a tune up on it, and drive it, while building a nice little small block chevy. But, thats me. -Russ-

 

[66chevypu]

I have a '65, 1 ton, panel truck with the 305E V6 in it. I haven't owned it long so I can't give any history. It starts well and runs well. Look at www.favorites.com/~jolly/gmctruck.htm for the best description of the GMC V6 engine. Good luck and keep us posted.

66chevypu

 

[78subgeorge]

Nobody home this afternoon at that link.