Saginaw trains rebuild

[Jek9016]

i know the Saginaw trains is not recommended for higher hp engines, but does anyone know of a shop that can rebuild them to to make them stronger or upgrade?  I actually like the wider gear ratio.  I still have the stock 10 bolt with 3:08 gears, but plan to switch to a moser 12 bolt with 3:55.  I'm concerned about having too low of a 1st gear if I went with a m21 etc.

[HustleRussell]

Imo. Forget the Saginaw transmission and high $$$ rear end. Spend that money on wide ratio Muncie and 8.5" rear end from 72 - 79 nova. Good luck.

[Stingr69]

IMO - Run the saginaw until it actually breaks and then make the call. No need to swap it before. 

Muncie was designed by GM to work in this application.  What are you doing with your car that makes it a bad choice? 

[X33RS]

I'm thinking he is concerned with the gear ratio compatibility.   The 2.20 first gear M21 Muncie was available with 3.55's out back in a few different vehicles.  I've driven this combo and find it works okay as long as you keep stock tire heights of around 26".  If you go throwing 28" tires on it there is a noticeable difference in the amount of clutch slipping that needs to be done.   The effective overall ratio with this is 7.81.

You get nearly the same overall first gear ratio with the 2.52 Muncie and 3.07 rear gears.  I've also ran this setup in 2 different cars without complaint, easy to drive with 26" tires.  I actually liked this a bit better because I still have good take off, it feels the same going up through the gears as the overall final ratios are extremely close, yet I had a better highway cruising rpm with the 3.07 final. 

My favorite is a 3.55-ish final with the 2.52 Muncie.  It's quicker than the common 3.73 and 2.20 setup and has a little better cruising rpm to boot.

[Jek9016]

Thanks for the info about the 2.52 muncie.  I will wait to replace the saginaw until it dies, but first priority is to replace the stock 10 bolt.  What is the formula and data you use to come up with the overall ratio?
Thanks

[KurtS]

Why are you wanting to replace the 10-bolt? What kinda power?
The Saginaw and the Muncie M20 are almost the same ratios - http://www.camaros.org/trans.shtml#4speed

[JKZ27]

I'm using a Muncie M20 wide ratio with a 3.55 12 bolt and it works quite nice. 327 EFI makes probably about an honest 300HP. 10 bolt or 8.5 may have been fine but I wanted an upgrade that bolted in and looked right.

Aren't the 2nd gen 8.5 10 bolt housings a little wider?

[X33RS]

I'm using a Muncie M20 wide ratio with a 3.55 12 bolt and it works quite nice. 327 EFI makes probably about an honest 300HP. 10 bolt or 8.5 may have been fine but I wanted an upgrade that bolted in and looked right.

Aren't the 2nd gen 8.5 10 bolt housings a little wider?

Yes they are.  For a first gen Camaro, if you're after an 8.5" 10 bolt, you'll want to look at 71-72 nova's.  Possibly 73-74 as well if they are same width (can't remember)...  But the 8.5's first appeared in 1971 for the nova.  Still relatively easy to find.

70 and up second gen Camaro/Firebird rearends are the same width as 68-72 A body, just different mounting configurations obviously.