My brother owns a 2001 HD 2500 (non-4x4) with the 8.1 Liter engine, which is attached
to the Allison Trans. He asked me to look around to see if it were possible to
replace/swap the engine out of it with something more economical....basically, something
that doesn't SUCK-UP so much GAS! From my point of view, he probably won't gain much
out of it. He currently has about an 6-8 inch lift, 30+ tires, big heavy A** bumpers, etc.....
Either way, I'd like to give him a formal answer with a bit more knowledge than I have. If it's
possible and someone has more knowledge of it, please enlighten me a bit. What engine
size/year do you recommend? He also plans to leave the Allison trans in the truck, so he'd
need to find an engine that will mate to it without any extensive mods. Will the computer need
to be replaced?
Thanks up front...

He could go to a 6.0 from the Denali sold through some of the dealers like Sciggins Dickey in San Antone for like $3600 (completely new crate motor). Or buy one from a wreck. I wonder if the wiring is the same (might very well be) and then he would only need to change the comp. It may help a bit, on a side note if does decide to do it put me down as the buyer of the 8.1 and it will help him offset the cost of the new motor.

Mike

I'll talk to my bro, and see what his plans are now....I'll keep you in touch
if he does decide to go with the swap..

He could go to a 6.0 from the Denali sold through some of the dealers like Sciggins Dickey in San Antone for like $3600 (completely new crate motor). Or buy one from a wreck. I wonder if the wiring is the same (might very well be) and then he would only need to change the comp. It may help a bit, on a side note if does decide to do it put me down as the buyer of the 8.1 and it will help him offset the cost of the new motor.

Mike

put me second!
As far as swapping, with that late model of a truck he might do better returning it to stock, if he has the old parts and looking for a desiel. Unless you got a good deal on a complete truck,there are so many small details to make it work. The power acc and computer stuff work together plus exhaust etc.
steve

I know I'm late on the reply to this thread, but I'd tell him to stick with the 8.1. I don't know about the wiring, but I know the 8.1 has a completely different intake and (I think) exhaust. I explored the possibility of sticking one in my 1500 Silverado, 5.3 powered. The 4.8, 5.3, and 6.0 are all pretty much the same, but the 8.1 is different. I don't know that he'd see any mileage difference, anyway. My truck's a 4x4 with a 3" lift and 33" tires and it's only pulling 15mpg on the highway. All he'd be doing is giving up power, IMHO.

that 8.1 sure does suck up the gas tho. i have a 04 yukon 3/4 ton 4x4 and i only get 12mpg. that thing will climb a tree if you can get traction.