Hydraulic clutch for second gen. f body

[Trans Am Andy]

Looking for any information on a hydraulic clutch for my 1977 Trans Am. I have found that Keisler Engineering has a master cyclinder with reservior for about $280, but no bearing. I have found that Howe racing makes a bearing for about $132.

[adynes]

Hello Andy,
I might have some info that can help. Coincidentally, I am also building a 77 T/A, and my name is Andrew. I have done a lot of research on this topic recently. Just this afternoon, I finished mounting an LT1-sourced T-56 behind my Pontiac 400 using a shortened Pontiac bell housing. I sized the bell housing to place the T56 input shaft in the same relationship to the flywheel as the old Saginaw 4-speed. It turns out that the critical dimensions on the T-56 input shaft match that of the 4-speed. The problem is, even with the factory setup, there is not enough room for any of the hyd TO bearings I have found. According to my AutoCAD drawing, the dimension of the distance from the bearing retainer to the pressure plate fingers was 1.550”. The Howe Racing hydraulic throwout bearing has a compressed thickness of 1.652”. I double-checked this measurement on the car w/ 4-speed. This leaves no room for shims, and gives a 0.100” preload! I remember reading somewhere that Chevrolet used a couple different thicknesses of flywheels, so this bearing was probably sized for the short version (with more gap)? The Howe T-5 bearing is shorter at 1.516", but neither are intended for use with anything but a stock (clamp load) clutch. (EDIT: I spoke with a rep. from Howe. He said their bearings can be used with stiffer stock style clutches, just not multi-disk circle track type clutches.)Below is a list of all the slip-on hyd TO bearings I have found so far:

Howe Racing PN:82870 $150 Thickness: 1.652”
PN:82876 (T-5) $150 Thickness: 1.516”
http://www.howeracing.net/DriveTrain/Index-Throw-HydStock.htm

Southwest Speed PN:650620 $125 Thickness: 1.730"
http://www.southwestspeed.com/?sec=view_part&id=3214

Quartermaster PN:721100 $200 Thickness: ???
http://www.southwestspeed.com/?sec=view_part&id=9905

RAM Clutches PN:78125 $??? Thickness:???
PN:78130 (T-5) $??? Thickness:???
PN:78132 (Tremec) $??? Thickness:???
http://www.ramclutches.com/Products/street_hyd_release_bearing.htm

Mcleod Industries $375+ ???I can’t seem to find any useful info (dimensions) from their website.

Added:
Powertrain Technologies: Thickness: 2 5/8"
http://www.powertraintech.com/Files/Street-MAX.html

Because of my T-56 swap, I am only concentrating on slip-on style bearings. If you are using the 4-speed, there are bolt-on types that will probably work better. I am still waiting for responses from a few of the companies listed above. I will update information as I get it.

-Andrew

[adynes]

By the way Andy, sweet car. I love that stance/wheel/tire combo!

Does your car have a Pontiac motor w/ 4-speed setup? I would like to compare dimensions if you can get them. I would assume we would have similar results. My original combo was:
Pontiac 400, stock bell housing, stock flywheel resurfaced twice, non-original Saginaw 4-speed, 11" Stock type diaphram clutch.
At this point I am thinking that the Pontiac flywheel is thicker than a chevy's, and/or possibly a 11" pressure plate is thicker than a 10.5".

Has anyone else had any experience w/ hydraulic throwout bearings in a stock application GM car?