Transmission info needed

clay · Posted: Tue Sep 20, 2011 9:54 pm Post subject: Transmission info needed

I'm finally done with the cam swap in my cousin's Vortec 350 and need some help to get it installed in his truck. I need to know what the designation is for the transmission in his truck to buy a flywheel / clutch / pressure plate package. He has a 1983 4wd 1/2 ton pickup with a 305. It's a 4 speed granny low transmisson. On the shifter it has L - 1 -2- 3. It is the original transmission. I know what the flywheel needs to be but I know very little about manual transmissions. If there are any identifying marks or traits you need that may be on the case, etc., let me know. Thanks, Clay.

af2 · Posted: Wed Sep 21, 2011 6:24 pm Post subject:

Clay, I don't know what you mean but>>>

Run a 11" diaphragm clutch so the pedal stays lite and you will be good.

You know the fly wheel is weighted?

My son put over 60,000 on his Vortec/ NP 4speed without a clutch change. He was not nice to it either as I made 3 different rear drive shafts that broke the U-joint with 5500rpm clutch drops, so he wouldn't borrow moms Tahoe! Laughing

Big Dave · Posted: Wed Sep 21, 2011 9:48 pm Post subject:

clay · Posted: Wed Sep 21, 2011 9:50 pm Post subject:

Yeah I have the flywheel part - it needs to be the external balance for a one piece seal crankshaft. But I don't know what the transmission input shaft configuration is to order the clutch disc (spline count and diameter). We can measure it when he does the swap, I was trying to get a jump on it and order parts first. Like I said, I just don't know how many different manuals could have been installed in his particular truck or what the identifying marks, characteristics are, etc. and am after hopefully some quick guidance as to what it might be. Automatics I have decent knowledge about, but manuals - not so much. I really need to crawl up under it and look around myself instead of trying to get info from him. I'll try to get some pics this weekend and that should help the indentifying process drastically. Clay

af2 · Posted: Wed Sep 21, 2011 11:07 pm Post subject:

83 will be the 10 spline.

SMOKEmUP · Posted: Thu Sep 22, 2011 2:15 pm Post subject:

Based on what I could find it's a SM465 transmission.

SM465:
Make: GM Muncie
Length: 12"
Height: 18"
Weight: 175 lbs
Case: Cast iron
Top cover: Cast iron.
Gearing: 6.55, 3.58, 1.57, 1.0

clay · Posted: Thu Sep 22, 2011 8:10 pm Post subject:

Great! Hopefully that should be enough info for me to go on. If not, I'll be back..... Laughing

Thanks af2 and Smoke. Clay