5.3 in 81 K5 Blazer

Just got done a few minutes ago dropping a 2005 5.3 from an Avalanche with 4L60E in my 1981 K5 Blazer 4wd.

Used 1" forward plates. With those plates 4l60e with tranfer case adapter is 1/2" forward of position that the 305 with th350 and adapter was.

The stock manifold fit with 1/2" x 3/4" grind on passenger side to add a little room to manifold heat shields.
Fit without grind but was a little close
Need to cut front crossmember or notch it. Cut mine as I will make one up out of tubing that wraps around front of motor.

Other than a little mod on tranfer case crossmember as it is old long adapter style and I am using the new short height adapter. This motor was built to fit this truck.

I will take pictures soon and post them..

forgot to add that a stock mechanical fan with clutch will fit the existing radiotor shroud perfectly.

Hope this helps anyone doing a similar swap

Also for those looking for a 4l60e a 2005 one from a 4.3 silverado has the correct ls1 style torque convertor. Fits perfectly. I updated with corvette servo and shift kit.

I was able to get a 4.3 one for 500 with 10,000 original miles. The 5.3 ones were a lot higher.

did the converter pilot fit inside the crankshaft center? Usually on those you have to put a pilot extension to the converter is supported.

Yep there is close to a 1/2'' difference between the SBC (4.3,5.0,5.7) 4l60e used and the LS (4.8,5.3,6.0) 4l60e used...

The convertor extension fit completely into the hole on the 5.3. I test bolted the convertor to the flywheel and the extension went completely in and fit like it was meant for it. The convertor was built with the dished flywheel design. Dont know if it was just this one or they changed them in 2005 but it looks exactly like a lsx style convertor. I did not see any space where an adapter extension would fit.

Good deal, sounds like you're ready to roll. :thumb:

Would like to see some pics if you got them. I have a 77 K5 in the garage with no motor. It is screaming for a LQ4 or so Im telling the wife.

Does the T case bolt up to the 4l60? How does that work for VSS with PCM?

the tcase is the gm 6 bolt style np208 so it will bolt up to the adpater that came with the 4l60e. I was going to mod the tcase for a reluctor wheel but i may use the jags that run pinionmount vss. I do not like the aa kit that puts the vss between transmission and tcase as computer does not know correct speed in 4 lo