Ill I'm going to say is the only reason we haven't seen a 8.1 lay down big numbers yet is because I haven't got all my parts yet. And yes I did get 504whp and 640wtq on a 200hp shot.

 

I installed a 8.1 in my 1967 Pickup! It was awesome specially cause my truck weight 4100 with the engine in it, alot lighter then most of the late modle trucks running around. Turbo 400 tranny and 373 posi gears in my 2wd short bed, it ran awesome untill i put too big of a cam in it and got piston valve contact (valve float i belive) #5 piston come apart at thatpoint.

this motor in stock form felt very strong and the seat of the pants feel was unbeliveable in my truck.

I have some pictures of it on my webpage.

later

 

There is a buddy of mine thinking about putting an 8.1 in his 03 GMC SB. I would like to see if he goes through with the idea.

 

Are you planing to rebuild it and put back in the truck or another vehicle?
Mahle makes pistons with bigger valve reliefs for the 8.1's but they made to be used with a slightly longer 6.7 rod. The stock rod can be made to work by bushing the small end of the rod.

 

I rode in a friends modded 8.1 last night. I'm now a "believer". That things puts down ungodly amounts of torque right off the bottom. HPT scanned 525ft/lbs at 1,800rpm at SIXTY PERCENT THROTTLE. (Torque management).

I think Chevy should do this:

RCSB SS's. LQ9 6.0, 2wd. T56 or 4L65.

ECSB SS's. 8.1, 4L80, AWD.

 

Crank on 8.1 uses a new "micro-alloy casting technique". In essence it's "almost" as durable as a forged crank. Durability testing has hown this crank to be good for 500hp. It is capable of more but @ 500 it still falls within GM's long term testing specs. The crank also has knife edged counterweights on all thows as well as rolled fillets.

Pistons on the 8.1, as previously mentioned in this thread, MUST, be replaced if going FI. This harkens back to the same problem with blown applications with the HyperCrap LT1 pistons.

Heads, Intake & manifold. A new set of Aluminum Heads, Intake manifold & cam will give you 525hp & over 600flts torque N/A.

 

Here's that truck that was customized!! It has the 496ci and also the 4l80E tranny. Really nice love the Hugger Orange color!Also has air ride!! If i could offord it i would swapt my 5.3 for the 8.1L always loved the big blocks good power for the 496 310hp and 520Tq!!!!

 

Here's that 496ss bitchin truck!!! Gots the 8.1L and the 480lE tranny also has air ride.If i can offord it i would do the swapt and built that 496 into more power!!

 

....i remeber reading on the truck i loved it but i couldn't ever find it.Man i love that truck