Trouble finding clutch parts

[Funky61]

I ordered the Perfection Driveline 04-528 directly from them, and they only had the one in stock. It is listed in their catalog as fitting the 305 and 351 six cylinder.

It looks a lot like the photo of the M-Pact 04528, but it looks like it will not work.

So am I correct that this will not fit?

[BobBray]

I don't think that disc will work. This is the same old problem, the hub protrudes out too far on the flywheel side and hits the pilot bearing.

[jerrspud]

Originally Posted by Funky61

I ordered the Perfection Driveline 04-528 directly from them, and they only had the one in stock. It is listed in their catalog as fitting the 305 and 351 six cylinder.

It looks a lot like the photo of the M-Pact 04528, but it looks like it will not work.

So am I correct that this will not fit?

disk is backwards.

these are the new numbers that fit
kit https://www.rockauto.com/en/moreinfo...=1993&jsn=1326
disk https://www.rockauto.com/en/moreinfo...10605&jsn=1342

[BobBray]

I ordered an M-Pact 04528 from Rockauto, and it is the same as the Platinum Drivetrain 04-528 as you can see in the pictures. Member 63gmc4x4 has used the Power Torque (O'Reilly's) 70375-HD1 clutch. It has an 11" flat disc and a diaphragm spring pressure plate. The GMC V-6's all came with 3 lever Borg & Beck style pressure plates which have more clamping force than a diaphragm spring type. The 70375-HD1 is for mid-90's GM pickups. M-Pact sells an 11" 10 spline disc part #383348 that has a flat flywheel surface, I have heard that this disc works on a GMC V-6 and can be used with a 12" pressure plate, but I have not tried it myself. Note that most GMC V-6's came from the factory with 11" clutches but a 12" can be used. Next week I will call M-Pact and see what they have to say.

[BobBray]

Another view of the M-Pact 04528 disc

[Funky61]

Jerrspud added the link to 63gmc4X4’s thread of a clutch disc that would work. I sent my disc that did not fit back to Platinum Driveline and had them find me one from a 1996 Chevy truck 1500 with the 4.3 V6.

Here is that disc, #381066, which cross checked to 70375 and 04121.
I have it here compared to a NOS GMC 11” disc I bought awhile back.

The springs are more recessed in the newer disc and it sits flatter, but the cone is taller on the original by about 3/8”.

[Funky61]

A few more photos; New disc on left.

Thanks to Jerrspud for updating numbers on the throw out bearing and 63gmc4X4 for his efforts on digging further to find the disc.

[BobBray]

The cone on the transmission side shouldn't make any difference. The 381066 disc is 11", correct? I have not called M-Pact yet, I am thinking about trying an M-Pact 384195ST1, it's a 12" diameter 10 spline 1.125" disc for a 1993 Chevy/GMC 3500 that appears flat on the flywheel side. I want to see if it will work with the 3 lever 12" pressure plate that comes in the Platinum/M-Pact 04528.

https://www.rockauto.com/en/moreinfo...=10605&jsn=648

[Funky61]

Yes 11" on the disc. That link and pics on the site seem looks like it may work.