I'm swaping a LS into my car it came with a 99 Z28 PCM and harness. I found a 4L60E out of a 2 wheel drive 2000 truck.
Will the 99 PCM work with the transmisson?
What can I do about the C-beam?
I hear I can swap my 700r4 tail shaft over with a 6 bolt to 4 bolt adapter but what about the difference in the VSS?

 

There are alot of variables to work out with your LS engine swap into your 1991 Vette.

I will concentrate on the transmission for you and let the others here worry about the wiring and engine transplant details.

1st off, what size is the LS engine?
Is it a 5.7, 6.0, or the 7.0 liter engine?
How much projected power and torque at the engines flywheel?
Are you street driving only?
Are you building a dedicated drag race car?
How high will you turn the LS series engine?
Will the engine turn 8k rpms and higher?
If driving on the street, do You have a serious leadfoot like me where you run your Vette to 150+ and higher?

Your 1991 C4 has the 700R4 trans originally.
That would be my 1st choice to rebuild, blueprint, and modify with carefully selected parts to handle north of 600 HP with a built LS series engine.
That's if you can live without the 4L60E trans and computerized shifting control.
The reason why I say the 700R4 is because you already have the correct trans that fits your Vette.
You can use a 4L60E trans too if that's what you want to use.

I built my 87 vert 700R4 with GM NOS- early state of Ohio production forward and rear reaction 5- pinion planetary gearsets and full GM NOS needle thrust bearings throughout the transmission.

Later and current over the counter GM 4L65E 5-pinion gearsets are made in Mexico.

It takes some searching and knowing the right people to get the Made in the USA - Ohio 5- pinion Gearsets.

For forward thinking of my future 410 sbc engine swap.
I used only the best parts available.

Brian

 

built/forged 5.3 347 iron block with 241 heads

MS3 cam
237/242, .603"/.609", 113 LSA

LS6 Intake

Wiring harness and PCM tuned for the set up.

Made 380RWHP in the camaro.

I was hoping it would be easier to adapt the 4L60E than it would be to make the 700R4 cooperate with the swap.
Also i bet i would spend just in parts alone on the 700R4 what I'm paying for this built 4l60E.
"It has the race pack clutches, Upgraded B sun shell, 5 planetaries, corvette servos, shift kit and more"

 

To my knowledge, no one makes a C4 tailshaft housing for the later 6-bolt 4L60E trans case.

You would need an early 4L60E trans case in good condition, swap all internals over. Then you can bolt up your C4 tailshaft housing easily.

The only aftermarket C4 tailshaft housing I have seen in the last year is from PATC transmissions.
The $400 or $500 kit is for swapping in a GM 4L80E transmission into a C4 Vette.

Race clutch packs are nice.
I used Red Alto Eagle frictions and Kolene Steels in my 700R4.
Expensive rebuild kit.
Make most mouths drop here on C4 the price tag I paid last year for that kit.
So far, so good on the street and with my heavy right gas pedal foot.
8,000 miles later shifts just as beautiful, clean, and fast as the day i finished installing the rebuilt trans and drove away.

Borg Warner frictions are good frictions to use on the street.
They were OEM on all C4 transmissions.
Read the Borg Warner label and name on my original clutches of my 87 trans.
Most were like new after 23 years and taking my driving abuse.

Brian

 

PATC make an adapter ($$$ ) to put the 4 bolt C4 housing on the 6 bolt LSX trans
#6C4







They also make a crankshaft adapter to run a early 4L60E on a LSX engine

 

He is all set to go then !

 

That's what I need
along with a VSS sensor for a 96 vette. Hopefully that will work.
I just got back with the transmission and a 3000 stall.