8.1 & Allison swap into 1998 K-2500 Sub

**X-Hibition** · 11-07-2009, 12:33 AM

I don't know if this has been brought up or beaten to death but...

I'm on Craigslist and I spot a 2001 HD2500 being parted out with an 8.1 and Allison tranny. No problems with my big block or the 4L80E but, a larger engine and another gear. How do you go wrong? He also has the manual shift transfer case. What else do I need?

Does this swap work?

Thanks everyone.

**unplugged** · 11-07-2009, 12:47 AM

For starters, the harness and the ecm. Maybe Jimmie will chime in with more.

**Jimmiee** · 11-07-2009, 09:10 AM

Originally Posted by unplugged

For starters, the harness and the ecm. Maybe Jimmie will chime in with more.

I'm not familiar with that swap. Hopefully someone here has already done it?

**vncj96** · 11-07-2009, 10:48 AM

You are gonna be spending alot of money for the new drive shafts, transfer case if you have 4wd, ecm and anything else that would need switching, possibly even the fron 4wd drive assembly, i would just do a duramax swap. for the money it would be woth it, the 8.1 isnt a huge upgrade to the 454 my uncle used to have it and got rid of it and prefers the 6.0 over the 8.1 in a HD truck and have a couple cowarkers that said its really not a great performer and would have rather gone with a duramax. there is more performance out of the Dmax, 6.0 and the 454 has more possibilties then the 8.1, it just wasnt a popular engine, hence why it was short lived

**X-Hibition** · 11-07-2009, 06:43 PM

The seller has the ECM and wiring harness (and as I mentioned, the transfer case). As a matter of fact I can get everything as a roller for $2500.00. What really interests me is the tranny. Do-able?

If I use the 8.1 it will have a little work done to it, not too stock.