91ls1silverado

So What flywheel and clutch do I use for my ls1 5 speed swap. Its a 91 Chevy C1500 on a getrag 5 speed i believe. I tried using a 4.8 flywheel but pressure plate was off by a bit..i can't afford a t56 so anything would help thanks!

Pocket

iTrader: (22)

You need a 26sp input shaft on your 5 spd for this to work. Most v8 versions are. Use the BBC bell and a LS1 clutch. Either get creative with the fork or drill the front plate for a LS1 HTOB

tfi racing

iTrader: (2)

What do you mean by "off a bit"?The 4.8 flywheel should work with the stock truck 5spd,clutch disc and pressure plate.

garys 68

iTrader: (1)

Start over. Year and model of motor. Same info on trans, flywheel, clutch disk, pressure plate.
Also spline count on trans, what it was bolted to (SBC?), input shaft pilot bearing diameter, length.

91ls1silverado

There was a pin on the 4.8 flywheel that wasn't on my old flywheel and the bolts were off by a bit, and it was mounted to a 350. This is not the nv3500 my trick is a 91 people say nv3500 didn't come til 93...

garys 68

iTrader: (1)

So you're trying to mount a SBC pressure plate, clutch disk on a Gen III flywheel?
Remove the pins, ream out the 3 holes that are too small. I would have it balanced too before you bolt it up.
You could also try a complete clutch kit for the Gen III 5 speed if it will fit in the bellhousing.

91ls1silverado

Yes, and okay ill do that! Thanks man appreciate it

garys 68

iTrader: (1)

This thread might help with pilot bearing, inspection covers, etc:
https://ls1tech.com/forums/conversio...-ls-motor.html
If you would report back what worked, or didn't, on that thread, that would be great.

91ls1silverado

Thanks for the reply Gary! I did my research and people are saying they took out the pins and the sbc pressure plate fit good so i am going to get the 4.8 flywheel again and take out the pins and see what happens ill let you know what happens.

91ls1silverado

Oh and if i get the 4.8 flywheel do i buy the 4.8 starter or ls1 starter?

garys 68

iTrader: (1)

get the 4.8 starter.

BMR Tech2

iTrader: (5)

I had the same setup in my 68 c10. I used a 4.8 flywheel, and got a clutch setup from an older truck (basically any of the old 10 spline muncie/saginaw/NV style input shaft). all the pins lined up fine in mine and used regular pressure plate hardware for the 4.8 clutch. My stock 5.3 starter worked fine. I still have the whole setup sitting in my garage actually, I pulled it out and went stalled auto when I put my turbo setup on.

As far as the transmission, you actually have a Muncie HM290, they were the predecessor to the NV3500. Almost identical but are rumored to be a bit stouter than the later NV.

Bilster

iTrader: (21)

I'm not 100% sure but I think you're going to have to work out some adaption with the Vehicle Speed Sensor (VSS). You need a VSS to tell the computer when the truck is rolling...among other things. I didn't hook up the VSS on my truck and the thing stalled at every stop. Older transmissions often don't have provisions for a VSS. There are aftermarket adapters that fit into your speedometer cable connection of the transmission.