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Old March 31st, 2018, 12:58 PM
tommr tommr is offline
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Join Date: May 2013
Location: phila pa
Truck: 1947 Flxible Clipper Bus 29 passenger 401 M
Posts: 76
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Default Re: Allison 6 Speed GMC 401

The bus builder made engine chassis mount kits available in the 60s when these V6 motors were starting to become available. An owner could swing an entire V6 with the GMC SAE 3 flywheel housing, air brake compressor, brackets and pulleys from a 6500, 7500 or 8500 Series truck. Its was a quick and cheap upgrade that was light years ahead of the Buick 8. While our motor is very good mechanically it is underpowered. It will climb any hill or grade but it is be slow. Ive thought of adding a turbo but just not inclined. Later Duramax is getting pretty complicated but the earlier pre 2012 is very dependable and components are readily available anywhere. Aftermarket support is huge as well. Torque and HP is very adequate to keep up with interstate traffic in hill country. With availability of engine driven air brake compressor bracketry the swap is much more attractive. Fuel mileage would also be better than a gas engine. Axles could come from a school bus but what we really need is dimensional data from an axle builder. You could climb under a lot of vehicles and maybe not find what you need. Ive pretty much done all the work on this. Ive had help with some aspects of rewiring. Subbed out some light mechanical issues when it came out of the barn and subbed out a clutch R&R. Tom
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