Vortec 8.1?

[zraffz]

I've been reading about them and heard with bolt ons and a retune they are capable of 360+ horses and around 500 ft lbs; I figure it's perfect for a big truck and I've already rebuilt or switched out everything in my truck already except for the t-case, front diff, and motor... still to this day I question why I keep dumping money into this thing instead of just finishing my car lol.

I've heard they fit behind the old style transmissions and the block has holes for the old and new style motor mounts. Does anybody have any knowledge about how they will fit in a half ton (if it makes a difference for clearance the truck has a 3" BL)? I know it's based off any old BBC but I still have to ask cause of how the accessories/manifolds sit.

Also do I have the option to keep my 4L60E behind that motor? The trans was rebuilt about 15,000 miles ago by a reputable builder around here and he said it would withstand quiet a bit of abuse... whether it could handle that kind of torque or not I really don't know

 

[dirtyhick42]

I doubt the 4l60e will hold up for long behind a modified 8.1. Other than that I have no other knowledge on this subject or this motor.

 

[illinoisboy]

Well idk how it would fit and all but i pretty sure that your 4l60e would be like a bomb. From what i've heard the case wont hold too much even if the insides will.
dang it dirtyhick just beat me to it.

 

[zraffz]

Doubted it would hold up as well but the problem is once I were to change a 4L80E I'd have to change the t-case, axles, steering knuckles and hub assembly :/

 

[illinoisboy]

I dont think you would have to change the transfer case, axles (except the rear if its not a 14 bolt), or any of the others. But then again its possible im wrong.

 

[zraffz]

Eh I'm probably wrong... I hope so. These motors are so cheap it would be amazing if it just dropped in place and all I had to do was figure out the wiring/peddle for the electric TB.

 

[blackcoffee]

Interested as well. Think it follows the same procedure as a vortec 7.4L swap kinda. I think if you find the 8.1L out of like a 2000-2002 3500 van theyre based off the OBS and the PCM and the wiring will be pretty much the same. The motor mounts are the same if your going from a 5.7L vortec in a gmt400 i'm pretty sure aswell.. Someone chime in. Not sure what you should look for them out of though guessing the vans motors are down tuned.

 

[zraffz]

Interested as well. Think it follows the same procedure as a vortec 7.4L swap kinda. I think if you find the 8.1L out of like a 2000-2002 3500 van theyre based off the OBS and the PCM and the wiring will be pretty much the same. The motor mounts are the same if your going from a 5.7L vortec in a gmt400 i'm pretty sure aswell.. Someone chime in. Not sure what you should look for them out of though guessing the vans motors are down tuned.

I've seen quiet a few on ebay from trucks; the motor mounts are in different locations but the block has holes for the old style mounts as well as the LSx mounts. These motors seem like a great bang for the buck. I am aware how heavy they are but worse case scenario I just adjust the torsion keys a hair.

 

[vervepipes]

subscribing, bought my truck to haul, what better motor that's near-plug and play...

 

[zraffz]

Only research I can find is in a '88 one ton frame, he had to notch the frame for the AC compressor and exhaust manifolds. Also found a 2003-2004 1500 that did the swap and it was a direct drop in fit.

I think I'm going to be the guinea pig on this one unless somebody has done it and can provide more information. People have put them in the two frames from the year before and after the OBS.