going to a carby 408

[aussiesteve]

I am in Australia and dont have access to junk yards full of these trucks and i have the only truck like mine in Sydney and everyone loves it.
My vehicle is a 1993 GMC c1500 2x4 5.7 4L60e, the original engine is leaking oil, tired and had poor ownership since it was improted. I have a fresh 408sbc and a 750 holley vacuume sec carb i want to install.

I just found if i remove the tbi and swap the old 350 motor the gearbox will require a stand alone control unit. there around $450 to $650 bucks.
i just found the 4l60e has connection on the brake light switch on the brake pedal, and the speedo in the dash will not work as its linked into the tbi and the auto gearbox.
what a mess.

i want to drop my fresh 408 chev in and run a 750vac sec carb i have spare.
i dont want to start getting into changing instrument/ speedo panels as most of the aftermarket stuff is junk anyway and the factory setup works perfect.
what a nightmare just the swap the engine.
i dont want an LS as there too expensive here used,
i dont want a holley efi as there un reliable and wont be long till its obsolete.

 

[Sean Buick 76]

Personally I would do one of the following options as the 4L60E are very fragile trans when exposed to torque.

1. Find a 4L80E and swap it in
2. Swap in a Th-400 and skip the Electrucal issues
3. Swap in a stick shift NV-4500

 

[Drunkcanuk]

Another option to look at would be a manual valve body in the 4L60e. I believe that may work, could be wrong though!!! Lol

 

[PlayingWithTBI]

Upgrade to a 16197427 PCM from a 94 or 95, it'll control your trans just fine

 

[Sean Buick 76]

Yes a manual valve body works too.

 

[Schurkey]

Perhaps a moderator will move this thread to the LSX + Carb Swaps sub-forum.

 

[aussiesteve]

Personally I would do one of the following options as the 4L60E are very fragile trans when exposed to torque.

1. Find a 4L80E and swap it in
2. Swap in a Th-400 and skip the Electrucal issues
3. Swap in a stick shift NV-4500

4l60 came in ls1 cars. The cops had no trouble with them
1st gear is a joke
The 4l60 is a th700r4 and junk
Mine has a full on heavy duty kit fitted and will take 600hp.
My old 408 is only 410hp.
I am not racing it as its a daily driver

 

[Sean Buick 76]

Then just add a throttle position sensor to your carby and use the stock computer to control the 60E.

 

[Erik the Awful]

The Holley Sniper uses off-the-shelf components. The TPS is off our trucks and the wideband O2 is from a Dodge truck. Parts availability will be good for a long while. The downside is that I know these things because they failed on mine.

 

[Schurkey]

The Holley Sniper uses off-the-shelf components. The TPS is off our trucks and the wideband O2 is from a Dodge truck. Parts availability will be good for a long while. The downside is that I know these things because they failed on mine.

Are those parts ACTUAL OEM components, or cheap-junk aftermarket replacements?

Knowing Holley, they're bottom-feeder aftermarket replacements for the OEM-quality parts--which might explain your failures.

Point being, it was wise of them to use OEM-compatible designs, but they should have used actual OEM parts. Replacements will be available for a long time...but you're likely to NEED replacement parts.