SM465 Clutch kit suggestions?

[Chilly178]

Anyone have any suggestions on what brand/type of clutch kit to get for a 72 C20 350 with SM465? Pretty sure its a 11" clutch. Not sure weather to go ceramic or organic clutch disk, self aligning vs regular throw out bearing, etc. What do you guys use? Also anyone have a link/part number for a poly version of the rubber mount that the trans sits on the cross member? I already have the engine mounts I would just like to replace that mount. Thanks.

[Mike C]

IME, most SM465 clutches are 12". I would just buy a complete clutch kit off RockAuto. Most run about $100.

If you are lucky, you may score one on Clearance. I bought a complete one with a puck style metallic clutch for $40. :-)

['68OrangeSunshine]

A '72 flywheel will be 12''. '71 and earlier will be 11''.
I used the Centerforce II clutch set up on both my '71 GMC Jimmy w/ V8 350/SM465/NP205, and also '68 C/10 w/ 292 L6/SM465.

[Chilly178]

Oh okay. So this flywheel won't work with a 5.7 vortec and 12" clutch? https://www.summitracing.com/parts/n...8/applications

['68OrangeSunshine]

If you don't have the original '72 12" flywheel, then I don't think the universe will come to a screeching halt if you used an 11". But I could be corrected. The SM465 didn't get a 12" flywheel til MY 1972. '68 thru '71 SM465s used the 11". I guess the 11.85" is called the "Twelve Inch."
If they're the same price get the bigger one.

[palallin]

My '69 SM 465 K-10 has a 12". I am pretty sure it came that way.

[57taskforce]

I got a 12” luk from NAPA for my K20. I was around $120 for everything except for machine work to my flywheel.

[CastIron]

I used a Luk clutch with my 3 speed. They are original equipment on a lot of GM cars and trucks. Which exact one for your application? I'm not sure, but I can't imagine there is too many different clutches for these old trucks. Probably only a couple of sizes?

[BCOWANWHEELS]

oreillys are lifetime guarantee for around 100.00. organic is oem and easyiest on flywheels. 12 in if it will fit but 11 h/d would be more than enough.

[Chilly178]

I guess i'll have to tear the engine out and look at the clutch to see for myself. Seems like its either 11.85" or 12". It kinda matters because the flywheel I was looking at takes a 11.85 max. Steel or cast flywheel by the way?

[Mike C]

The OEM flywheel will be cast iron.

['68OrangeSunshine]

Originally Posted by Chilly178

I guess i'll have to tear the engine out and look at the clutch to see for myself. Seems like its either 11.85" or 12". It kinda matters because the flywheel I was looking at takes a 11.85 max. Steel or cast flywheel by the way?

I think the so-called 12" is actually 11.85" if measured exactly. But check with someone else. I'm not an expert.
Steel or cast-iron? IDK.

[BCOWANWHEELS]

no need to pull engine or trans............ just slide trans back about 8 inches. steel flywheel not needed. cast is fine in fact just resurface it. new pilot bushing and throwout brg. I don't think a 12 in will fit in our bellhsgs. 11 in is biggest. been a while. check clutch fork for wear............

[57taskforce]

Originally Posted by BCOWANWHEELS

no need to pull engine or trans............ just slide trans back about 8 inches. steel flywheel not needed. cast is fine in fact just resurface it. new pilot bushing and throwout brg. I don't think a 12 in will fit in our bellhsgs. 11 in is biggest. been a while. check clutch fork for wear............

My 72 has a factory 12”