OT- V12 GMC Gas Engine

Hi, Hutchy.
I think they were mainly used in tanks. I have seen another article about them in the past and I think there may be a video on Youtube.

https://www.youtube.com/watch?v=vtfPFLQMbUM

In fact, there are several videos there. Enjoy.

Just my 0.02.

Here’s a small article from an entertaining guy
King of Obsolete. Mostly international td6 and 9’s but he’s got a few Cats too
https://www.kingofobsolete.ca/V12_GMC_KoO_WEBSITE.htm

They were used in gmc crackerbox trucks https://youtu.be/puJaDfB4UFM if you scroll down in the descriptionsed in crackerbox and other gmc trucks i have read they could haul but hate to be fueling them at todays petrol prices lol

Actually a very sought after engine, like it has been stated they were used in GM trucks and firetrucks. They are 2 v-6s joined up, beautiful sound and smooth as glass, big appetite. I am not sure if Seagrave used this engine or one of it's own.

They used four heads from a V6. I know a guy who has/had one.

had one in a farm truck many years ago. also had it's counterpart the V6. very good dependable simple engine.

If I remember correctly, the GMC V-6's came with 305, 351, 401, and 478 cubic inch configurations. It sounds like the one you are talking about would be two 351's joined together. My dad had a 1965 GMC with the 305 CI in it. It wouldn't pass a service station without a need for gas and was not overwhelmed with power. A lot of the folks that had them often referred to them as boat anchors.

If I am not mistaken GM turned that v-6 into the Toro Flow diesel, a dismal failure, but in their defense it was before turbo-charging became popular, they may have been something with a little push of air, with maybe a 71 series blower sitting on top, 5 or 6 pounds of boost goes a long ways. I don't know if they were a pre-cup engine or a DI engine, makes a big difference as well, modern bolts and gaskets would make a difference towards making power and longevity.

My dad was in the army in WWII. He was in the motor pool stateside. I don't know if it involved the GMC V-12s or another engine, but he said their job was to take the GMC engines out of brand-new tanks and put Ford engines in them.