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66birdman
May 28th, 2014, 10:40 AM
I have a 66 C15 with a 351E and a SM420 in it and I was just given a freshly rebuilt 250I6 out of a 74 Nova. Any ideas on what would be required to swap it in there? Motor mounts, cross member and a bellhousing I assume. Anything else I am not thinking of? I really dont want to ditch the 351 but parts are hard to come by and stupid expensive.

BarryGMC
May 29th, 2014, 06:30 PM
Motor stands bell housing convert the throttle to cable type. But why? Is the 351 dead or dying? If it is its not hard to find a good 305-351 v6. Barry

quest
May 29th, 2014, 06:40 PM
Motor stands bell housing convert the throttle to cable type. But why? Is the 351 dead or dying? If it is its not hard to find a good 305-351 v6. Barry

Ditto, whats wrong with your 351? sure would be a nice motor to keep in the truck. I wish mine had that one!

GMCDAC
May 30th, 2014, 04:05 AM
I have a 66 C15 with a 351E and a SM420 in it and I was just given a freshly rebuilt 250I6 out of a 74 Nova. Any ideas on what would be required to swap it in there? Motor mounts, cross member and a bellhousing I assume. Anything else I am not thinking of? I really dont want to ditch the 351 but parts are hard to come by and stupid expensive.

If you have to do this swap I can take pictures of frame towers and engine mounts and a 250 with the bell housing. Also have some other pieces like mechanical clutch linkage and brackets I can take pictures of also. These parts came from a '64 Chevy pickup.

DAC

bigblockv6
May 30th, 2014, 04:15 AM
You're losing 100 cubic inches as well as the novelty of a GMC V6 powered truck. If there's anything wrong with your 351E spend the money and have it rebuilt. True parts are harder to find now than ever but give it some time or find another V6 that's lower mileage or been rebuilt, even consider a 401 that pistons are being reproduced for.

66birdman
May 30th, 2014, 04:43 PM
The engine runs fine as of now. Compression tested at 115-125psi all the way around and a blow down test showed anywhere from 10-15% which is well within the acceptable range. I am just getting my ducks in a row for when something breaks that I cant find parts for is all. Unfortunately my "fixing the V6" fund was diverted to my cruiser restoration. Come to find out thunderbirds are insanely expensive to buy things for.

GMCDAC
May 31st, 2014, 12:21 AM
Your V-6 should outlive well ---- me anyway,-LOL! Don't know your age! Those numbers are good to go with no worries I would think. Get the T-Bird done and drive the heck out of your GMC too.

DAC

66birdman
May 31st, 2014, 06:18 AM
The only problem is massive oil leaks at the moment. The Tbird just got all new suspension, fresh rebuild on the 390, floor pans and now I am reupohlstering the seats. That all came to about 6 grand this month just in parts. I love my GMC but the bird is my baby. I use the truck as a truck and just keep it running for the most part.

bluestreak1854
January 29th, 2017, 11:41 PM
I have a 478M with an Allison auto transmission that only has 8696 miles on it with everything needed to install it. I also have a manual 5 speed and 4 speed brownlite if your interested.