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| | | | Joined: Feb 2008 Posts: 207 Wrench Fetcher | | Wrench Fetcher Joined: Feb 2008 Posts: 207 | which one do you think would work the best in a AD big bolt the 401M and Allison 4 speed or the 454 with a th4000. | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | The 401 may be a lot narrower (60 degree V6), and help to fit in the frame and around the steering box.
What does the tape measure tell you?
Different folks like both engines equally as much, which one do you like more?
Grigg | | | | | Joined: Oct 2003 Posts: 5,152 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Oct 2003 Posts: 5,152 | The 401 V-6 makes lots of torque, but does not turn very fast. It was famous for terrible fuel economy. The 454 makes lots of torque and lots of horsepower, plus it will turn pretty fast. Mileage isn't great either, but better than the 401.
I've heard recently that there was even a GMC kit for retrofitting the V-6 into a '47 to '54 GMC and recently a guy I know bought a '54 with the V-6 in it. If you could acquire that kit or the parts that would simplify installing the V-6.
The 454 will require changing the steering but otherwise isn't a real difficult swap.
How are you going to use the truck? If its just for show or just for working locally, and doesn't need to run down the freeway the V-6 might be your best choice. If you want to move a load at speed the 454 will be more satisfactory.
My own choice would be the 454 but I'm a fan of big Chevy motors.
1955 1st GMC Suburban | 1954 GMC 250 trailer puller project | 1954 GMC 250 Hydra-Matic | 1954 Chevy 3100 . 1947 Chevy COE | and more...
It's true. I really don't do anything but browse the Internet looking for trouble... | | | | | Joined: Feb 2008 Posts: 207 Wrench Fetcher | | Wrench Fetcher Joined: Feb 2008 Posts: 207 | this truck will be my pulling rig but it will also get driven empty a lot will probably do lots of driving at 70 to 80 MPH i just thought the 401 and Allison would be kind of neat i already have the 454 in the truck but no exhaust manifolds or radiator(i don't have them)i also have a dana 70HD with 8 lug hubs out of a Chevy 1 ton so i was also going to get a 4X4 front axle with the 8 lug hubs so i could use the truck in the winter too. also how much stronger is the Allison compared to the th 400? | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | The Allison is supposed to be strong, but it is also heavy, and the one you have is not so modern any more. It is also not overdrive. Do you need overdrive to go 80 mph? A Dana 70HD is available with 3.54 gears as your fastest option. Lets say you run 8R19.5 tires, as they are good truck tires, they look somewhat better than 16" ones on a 2 ton truck, and are 33" tall. Then use this site to calculate rpm at 80 mph http://www.onlineconversion.com/bigger_tires.htmlooks like without OD you will be turning 2,900 with this combination, is this acceptable for either engine? Grigg | | |
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