Allison AT545 in D300?

[dustydog]

I'm amassing funds, time and parts to finally do a MAJOR overhaul, resto, build up on my Dodge. Looking for a school bus donor for permanent tranny and temporary 5.9 (plus to get my hands on the adaptor plate for tranny. I know that the tranny is pretty big but not excessive and the plasma cutter says it fits. My only concern is the power/tourqe rating for the Allison 545 seems lower than my target HP/TQ. I always thought when the time came to go full 'zoot' and try for the dyno tilting HP/TQ but #2 @ $5 ... maybe not so much but would still enjoy a good pull every once in a while. Any other suggestions for trans? Would really like a stick but it seems so much easier to use the AT545 or? Already have found a HUGE Dana 125 from an F-550 and the master cylinder to boot. I just want a reasonably hard running MECHANICALLY injected truck that can surprise the unknowing, last another 500,000 after rebuild and get decent mileage. I have that stupid 727ish 3spd. and still manage to get 15-17 MPH around town and have gotten as high as 24 on the highway if you keep your foot out of it and I'm empty which is pretty good for an auto with the aerodynamics of the 'Nimitz'.

 

[towcat]

You better do your math.....
the Dana is going to put you outsde of your powerband, I'm going to be putting in a 10.25 sterling with 3.55 posi in the Sulaco. In OD, this will be within 10% of what the intercooled Dodge of the same vintage has(3.42). If grunt is your goal, then look closer at a Dodge Dana 80 in a 1ton chassis. The ratio will be more to your liking when you finally drive it.
As far as a Ally AT545, have you driven one yet? They really suck up the Hp out of your motor and there is no compression decel capabilities with the trans. You will need to look into a exhaust brake if you go with the trans.

 

[dustydog]

thanks 'cat

didn't research the big dana that much. know a guy @ the local salvage yard and he had pulled it from the truck. If I could get the taller gears the size and cool factor (square tubes) would be great. I'm beating the 70HD to death and I have those 'oddball' drums that you can't seem to find and the rears keep blowing cylinders so 90% of the time I only have fronts (!). Just want to make sure that when I replace something it lasts another 650,000 miles or so (I'll keep it going that long?). Now about auto trans choice... Want 'mechanical' auto (non elec) and enough longevity to last. yes i knew (I thought) about the 'shortfalls' of the ally 545 but if it is that power robbing and I'm not that bright when it comes to realizing the decel negatives of a tranny description. I just knew they were in school busses and thought I could source a temporary engine and 'buildable trans for a reasonable fare. I'm a bit impulsive when I'm shopping and have $$$ in my pocket. Have had the truck since 2000, got it for repayment of $600 debt (172,000), idled but didn't drive (rotted fuel line), made 87PSI (oil) and was looking for a Cummins to put in a 52-54 Chevy 6 series straight truck for work, finally found a truck and engine would not fit unless I started cutting up the old truck and well I didn't think it was right (impulsive shopper). What trans suggestions would you have? Readily availble (school bus?), simple, strong and just in case (buildable to handle higher HP/TQ)?