Clutch Pack Questions.

[mda440]

I'm in the middle of rebuilding my 727 and found the front clutch pack only has 3 clutch plates and the rear clutch pack has four. I've tightened up the clearances on the rear clutch pack, but I'm kinda worried about the front pack with only 3 discs. Is this enough for a 500hp big block? I'm using good clutches, but I've read some 727's had up to five discs in the front clutch pack??? Is this okay to continue rebuild or am I going to smoke this thing pretty quick if I install it???

 

[Duster346]

I'd use at least 4 frictions/4 steel plates in the high gear (front) clutch. You'll want the extra holding power with a true 500hp. I typically set mine up for 5 frictions/5 steel plates in the high gear clutch. This can be accomplished by using thinner friction plates, and selective snap rings. You'll want .010"-.012" of clearance for each friction plate. So if you use 4 frictions, you'll want .040"-.048" clutch pack clearance. You don't want to be to tight here, as you'll burn the frictions in a hurry.

You should have 4 frictions and 3 steel plates in the forward (rear) clutch pack. You'll want .035"-.040" clearance there. You can get that clearance with selective steel plates, and selective snap rings.

Who's clutches are you installing? I'd also recommend a good reverse pattern valve body with low band apply in 1st gear.

Hope this helps

 

[Mrmopartech]

You can fit 5 disc and plates by machining out the bottom of the drum to axcept the five on five set up and set clearance as normal,mrmopartech

 

[Thrasher]

Sorry to dig up such an old thread, but a question on front packs:

I've read that the number of springs in the front clutch pack (727) varies, depending what the tranny was bolted to when it came off the assembly line... what difference does it make if you have/use more or less springs?

 

[fishy68]

Sorry to dig up such an old thread, but a question on front packs:

I've read that the number of springs in the front clutch pack (727) varies, depending what the tranny was bolted to when it came off the assembly line... what difference does it make if you have/use more or less springs?

Thrasher if your trans is stock less springs are ok but if someone has changed the kickdown apply band arm to a higher ratio and/or installed a shift kit it's better to have 12 or more springs. Too few springs lets the high clutch to apply to fast, before the 2nd gear band is fully released which causes overlap and that is real bad. It will destroy a trans. fast and actually slows the car when it shifts. What it comes down to is everything needs to be matched. If you only have a 2.9 or 3.2 ratio lever you only need 9 or 10 springs. If you have a 4.2 or 5.0 ratio lever you need 12-15 springs. The spring count, band ratio, oil pressure and sprig rates in the valve body all determine how firm a trans. shifts.

BTW: From now on you might want to start a new thread with your question even though there may be an old one like this one. You'll probably get more attention that way.