Just wondering if the Allison can be bolted up to a 6.0 gasser? Not sure if the bellhousing is the same between the 6.0 & 8.1, im sure someone on this site knows. And if the bellhousing pattern is not the same are there any adapters to make the Allison work behind the 6.0?

I think it would fit, as the 8.1 is available with either trans.

Problem would be the hp loss you'd see with using the Allison.

Different bellhousing IIRC. I also don't think you could get the 8.1 with any other a.t. except Allison after the Allison became available.

I think it's the standard GM bell housing. The 8.1 is available in the Avallanche or the Burb with the 4l80 and the motor is the same as the 8.1 in the HD's.

Actually the transmission in the Avalanche or the Burb with the 8.1L is the 4l85e.

Its the same old bolt pattern that GM has used sense the first small block. And yes a 6.0 will bolt to it but don't wast your time a properly built 4l80e will hold anything that a 6.0 can muster.