C 20 want to install L 96

[Arnulfo]

Greeting from beautiful LOS ANGELES CALIFORNIA. I have a 1970 C20 CST that needs a new motor. The one it has in it now is a non original 350 . Transmission is original. I want to install a L 96. Will it bolt up to the original Th400 transmission? Eventually i hope to install a newer transmission possibly a 6L90E
if it will bolt up without too much hassel. This is my work truck. I do not want to have to cut or notch the frame if i can avoid it. I have never done an ls swap but i have no doubt that i can do it. Just need a little guidance on issues that may arise . I have been wrenching on my own cars and cycles since i was 16. About to turn 60 in january. This is a great site. People here seem laid back and more willing to help than criticize. I hope to contribute by starting a thread when i do the swap. It wont be for awhile though because right now im in the middle of repairing the crumbling foundation to my home. Thank you in advance for any and all help.
Arnulfo

[clinebarger]

To bolt a TH400 to a LS (That didn't come with a 4L80E) You will need a Flexplate & Spacer, http://www.summitracing.com/parts/atp-z270

If you want a 6L90E....It is best to go that route in the first place, Just my opinion.

Truck exhaust manifolds will not clear your frame, V8 Trailblazer/Envoy/Rainer/Isuzu Ascender/Saab 9-7x manifolds fit. Or swap headers, I don't recommend headers on work trucks.

Are you going to run air conditioning?

You will need motor mount plates to retain the factory motor mounts.

You can modify the engine harness yourself if your up to it, BP Automotive makes some really nice harnesses if you want to go that route, Speartech also does a good work, PSI used to do good work....I have fixed quite a few of their harnesses lately.....They seem to pin stuff backwards.

The ECM will need some reprogramming.

Electric fuel pump, Corvette Regulator/Fuel Filter, High pressure fuel lines.

You can run a Mechanical Fan Clutch, I find a Fan & Clutch from '96-'00 350 Vortec trucks work the best.

You can adapt the air intake system from the L96 to fit your truck.

The original 4 core radiator can be reused if in good shape. Have a radiator shop "silver solder" a 3/8" hose barb on the passenger side tank for the steam line.

[Arnulfo]

Thank you for the very helpful information clinebarger. I agree that it would be best to install the 6L90E at the same time. If the funds are available I will definitely do that.based on what I have read on this forum, I will need to install a HIGH HUMP to make the 6L90E work. Yes I do plan on having a/c. The truck came with it from the factory. I'm hoping I can relocate the compressor to avoid having to notch the frame. I think I read somewhere on this forum that DINGO makes brackets to do that. Good to know that the original 4 core radiator will work. The one on the truck now is less than 1 year old.
I believe the rear end on this truck is the 411 gear ratio.It has the leaf springs and coil springs. How do you think that will work the the 6L90E ? My opinion about headers on a work truck is the same as yours.Dont want them. I want the truck to be a reliable strong running work truck with a bit more power than what I previously had. Im thinking with the L96 and hopefully a 6L90E combo I will have that.
Arnulfo

[clinebarger]

You can "Massage" the trans tunnel with a hammer, It is mostly the seam that's in the way.

A 6L90E will work great with 4:11's.

Does the original A/C work now? You can get a lot of time & money into restoring all the Doors, Seals, Ducting, Actuators, Cables, 134-a condenser, Evaporator core, Barrier Hoses......Then to find out theses systems don't work well (To today's standards)

A Vintage Air "Sure Fit" kit http://www.summitracing.com/parts/vt...del/c10-pickup Installs very easily, Gets rid of the Evaporator box under the hood, Cools great, And most of all....Has about twice the air volume compared to stock.

Don't just order that kit....It will come with a V-belt compressor, Call before ordering!

[Arnulfo]

If I can get away without cutting the floor to get the 6L90E in that would be great! The ac does not work. Sounds like the vintage air kit is the way to go, as long as I don't have to cut any part of the firewall or interior metal under the dash. Although this truck is not now nor will it be 100% original, I am anal about not cutting any part of the body or frame. Thank you much for the sound advice Clinebarger.
Arnulfo