vortec 6.0 or vortec 8.1

[95z71performer]

I know I might sound crazy but this would be awesome if I could get a nice wrecked donor truck with an allison trans and 8.1 just general opinions of if it would be a cool swap to get done or if a wrecked 6.0 would be enough with a 4l80e for my truck

and I meant for this to go into the ls section

 

[TylerZ281500]

a 6.0 would be alot easier, as its a typical lsx motor mount where as the 8.1 is different and not many people have done it. i do love the 8.1 motors though because after a good valve port and polish job, matched ports and bigger throttle body, exhaust cam and tune. 670hp and 800ftlbs was awesome in an 01 2500 hd

 

[Chewy1576]

The 8.1 has bosses to use standard big block motor mounts, so no special LS motor mounts needed. I looked into this option as a replacement for my 350, but decided on a 383 instead.

 

[sewlow]

8.1's are thirsty low-end torque monsters. Apparently they don't like to be wound up, rpm wise, either.
I've looked into them too, as a swap into my '98.
From what I've read about Josh's (Fastorange) experiences with his & from a few others, is that they also have a bit of a prob with excessive oil consumption. Even on low mile examples. A different viscosity than what GM stipulates helps.
I've read an article on FSC or GMFS where a member there did this swap. It required a bit more work than the average LS swap.
Can't find that post. Someone here recommended that to read. Maybe they'll see this & repost the link

 

[Birchyboy]

There's a guy on the Tahoe forum that transplanted a Duramax/Allison into an OBS Yukon. That'd be killer.

 

[someotherguy]

I believe to get the Allison to fit in anything less than a 3500HD (which the last year or two were available with) you either need a body lift or major trans tunnel surgery.

The oil consumption issue on earlier 8.1's may be related to a crankcase vent tube in the bottom of the intake; a member on 3500HD found that between an older and newer model, there was a bend in the newer one, apparently to prevent it from directly sucking up oil. While rebuilding an older model he replicated that bend; after the rebuild it no longer used oil - where previously it had from day one.

And no big block likes being wound up, unless you do a lot of work first.

Richard

 

[sewlow]

I believe to get the Allison to fit in anything less than a 3500HD (which the last year or two were available with) you either need a body lift or major trans tunnel surgery.

The oil consumption issue on earlier 8.1's may be related to a crankcase vent tube in the bottom of the intake; a member on 3500HD found that between an older and newer model, there was a bend in the newer one, apparently to prevent it from directly sucking up oil. While rebuilding an older model he replicated that bend; after the rebuild it no longer used oil - where previously it had from day one.

And no big block likes being wound up, unless you do a lot of work first.

Richard

Yup! Awful big pistons & valves to be throwing around @ 6000+rpm.

 

[Biggershaft96]

Is love to see it happen but they're not the quickest stock. You can pull down a house but a 5.3 will smoke ya.