[grapro]

: Just built a 355 for my truck and have a couple of questions which popped up during the switch over. I had a 98 sbc and I ran a 11 clutch assembly out of a chevy van with a 4.3 in it before and the crank has the smaller hole for the flywheel on it than the pre 98. Now I had to change a flywheel to the older style because of my crank and I cannot use my 11 inch clutch in it any more. The bolt pattern for the new pressure plate is now 11". Does anyone know who would make a 10" clutch disc with a 1 1/8 shaft and 26 spline. Or is there some style of flywheel whit a 12 1/2" pressure plate bolt pattern whith fits on the large ended crank? I contacted Centerforce and they thought they were made but did not have a number for it. I found 9 1/4" clutches from a chevy sonoma and a 9 3/4" for some Pontiac but no one has any available here in this part of Canada
Thanks

 

[ericnova72]

Maybe there is a cross-up of the #'s in your post, I don't understand??

The 11" disk and the 12" disk clutch uses the same flywheel-to-clutch pressure plate bolt pattern and even the same pressure plate, only the disk is different(it uses all of the pressure plate face at 12" but leaves a 1/2" gap around the edge with an 11" disk).

It sounds like you don't have the correct older flywheel, sounds like you have the one for the 10 1/2" clutch and not the 11-12". Is it about 12-3/4" diameter and 153 tooth count??

You need a 14" diameter 168 tooth flywheel for a 2-piece rear main seal crank, this is a common 283-350 and 396-427 internal balance flywheel. May also be listed as 5.0 and 5.7 engine 2-piece rear seal crank 14" 168 tooth flywheel. CarParts.com has a ton of these brand new on Ebay at about $55 shipped free.

I would consider the 10-1/2" clutch marginal in a truck or for any performance use, the 9-1/4 type stuff would be a joke, that's a 4 cylinder-small v6 clutch.

 

[grapro]

info

I have the 14 inch flywheel and it has 168 teeth the bolt pattern spacing on the pressure plate is 11 1/2 inches.
the flywheel number is 3729004. the largest disc that it can tke is 10.25 inches.
I'm not sure if I mentioned it before I have a t56 with the 26 spline input shaft.

 

[ericnova72]

Trans spline won't matter as far as the flywheel goes, just the disc.

What you have is the correct diameter flywheel, but not the correct application. Yours is drilled for the 10.5" clutch and was used behind the 250 straight six and low output 305 v8, typically in 1/2 ton trucks and base model Camaro's. You could have a machine shop drill the pattern you need as the basic 'wheel is the same, or just get the correct flywheel with the bigger pressure plate bolt pattern.

Might be more than one #, and I don't know if this is a service part # or the casting # from the flywheel but it is a correct # for the 14.13" flywheel with a 11-12" clutch and 2-piece rear main seal -- #3991469

Can't hardly believe Centerforce didn't know what you need unless customer service has tanked, it is the single most common flywheel ever used in a chevy car or truck, and the same dimensions as are used for almost every race application with a 14" flywheel.

 

[grapro]

Thanks

Checked it out and you gave me the right number, I think I screwed them up at centerforce because I wanted clutch aqnd flywheel all together as a kit. Not sure but they told me a 11" 26 spline disc was not right. Maybe my Canadian engish screwed them up.
Thanks Again