clutch kit

[sixbangr]

Can you use an 11" clutch to replace a 10". Six cylinder, 3 on the tree. Advance sells the 11" for $50 less than the 10.

[markeb01]

Yes and no. Either clutch can be used, but generally the flywheel, bellhousing, and starter are compatible as a set. In my experience the 10.4" clutch fits the 153 tooth flywheel, and the 11" clutch uses the 168 tooth version, unless you have an aftermarket flywheel drilled for both patterns. So the practical answer is "probably not" - without spending a lot more than the $50 savings.

[sixbangr]

thanks, great info.

[raycow]

Originally Posted by sixbangr

Can you use an 11" clutch to replace a 10". Six cylinder, 3 on the tree. Advance sells the 11" for $50 less than the 10.

If the clutch is for one of the trucks in your sig, and if that truck has its stock bellhousing, you already have a 168 tooth flywheel. Now the only issue is to determine whether the flywheel is drilled with both bolt patterns. If it is, you are golden. If it isn't, you will have to replace the flywheel, but you won't have to replace the bellhousing or starter.

Ray

[67Dad]

My sons and I have a slightly different question. Our rebuild orginally had a 292 with SM420 4speed, later swapped by unknown person to a 250with SM420 4speed. As the 250 had cracked cylinder, we decided to put a 350 SBC in it. Will the original 10" clutch work with the SBC or should we replace it with the 11" (if it matters). We've got it apart now, so now is the time to upgrade, so to speak!

Thanks.

Mark

[67Dad]

...update...we got parts for an 11". Hope to get it installed in the next few days. Progress...

[11echo]

67Dad ...The 10" clutch will work, but your "issue" is going to be if the 153 tooth flywheel will engage the starter where it's located on the 350 ...I'm not sure, but I'd bet it'll require the standard 168 tooth flywheel.
FYI ...I just replace the clutch disc on my 230 and was surprised to find it an 11" disc!!

[67Dad]

Now I'm a tad confused. We got a new flywheel...not sure of the teeth. Are you saying the teeth on an 11" are different than a 10" or is the difference in going between the straight six and the V-8?
Thanks.

Originally Posted by 11echo

67Dad ...The 10" clutch will work, but your "issue" is going to be if the 153 tooth flywheel will engage the starter where it's located on the 350 ...I'm not sure, but I'd bet it'll require the standard 168 tooth flywheel.
FYI ...I just replace the clutch disc on my 230 and was surprised to find it an 11" disc!!

[11echo]

Both 11" & 10" disc will work on the same flywheel, it's just the diameter of the flywheel that "may" be and issue.

[67Dad]

Ok. The "new" flywheel is the same diameter as the old one (from the straight 6). The question becomes, I think, will it work on the V-8 (350CSB), and IF NOT, will the clutch pressure plate, etc. bolt up to a V-8 flywheel?

Thanks to all.

[11echo]

All the flywheels I've dealt with have multiple threaded clutch bolt holes to deal with both size clutch disc, I don't think that will be a problem for you. Did your V8 come with a flywheel or a flex plate? "IF SO" then it would be the correct diameter you'll need for your V8 set up.

[67Dad]

...not yet installed, but we had to swap the flywheel to another...the teeth/diameter were correct but the center crankshaft mounting holes were different.

[11echo]

Now that suprises me! I had a in-line 6 (194) I was changing over to a manual 4 spd. I had thought a "regular" flywheel (168 T) would work, had it bolted up to the crank and was trying to stab it onto the trans but found out the flywheel was too large for the bell housing! I when down to the junk yard an go a small diameter flywheel (154 T) bolted it up to the crank and it slipped right in.

[b2948kevin]

Any update on this project, 67dad? I am swapping to a SBC 350 also, and am interested in seeing what flywheel and clutch size combinations were correct.

I am in the same boat with an SM420 mating up to a 350 one piece rear main seal. Looking for flywheel now, then I will order a clutch.

[67Dad]

Kevin,

We got a replacement clutch and flywheel from O'Reilly Auto. Our older clutch is probably OK, but we replaced it since everything was already apart--labor considerations if it went out later. The flywheel they gave us the first time did NOT line up on the bolt holes...we basically took the clutch in with the wrong flywheel they gave us the first time, and they found the right one. Number of teeth & diameter has to match starter design (depending on your engine year, etc.)...bolt holes have to line up mounting on engine side and clutch spline has to match on tranny side. Part numbers we used are: (Sachs Clutch: K5473-01 )... (Sachs Flywheel: NFW1003 ). (Ours is 93 SBC (VIN K as I recall) with 96 Vortec heads (irrevelant added info)).

[67Dad]

Kevin,

One more thing...we are running headers, and the stock clutch linkage will not fit--had to heavily modify (cutting, rewelding, very carefully designed and made) the existing linkage to make it fit. In essence, the pivot piece between frame and engine is too long for SBC...has to be shortened, along with the engine side mount adapter. Not trivial, but we couldn't locate a standard part ... probably exists somewhere though.

[b2948kevin]

Awesome! Thank you for the part numbers as well!

I'll have to take a look at my clutch linkage to put a plan in place on modification.

[padresag]

the z-bar for the clutch linkage is the same for all engs. the v8 takes ball stud that screws into the eng block. the I6 takes a ball stud pressed into a bracket that attaches to the eng. I believe that on some later sbc that the ball stud hole may have to be drilled and tapped. do not know what years that this occurs to though
ron

[67Dad]

Ours didn't "line up"...hence the modification. Sure would be easier that way if it did, though. Maybe Kevin's will.

[b2948kevin]

I will take a look and see if I have alignment. May be a week or two.

[padresag]

Originally Posted by 67Dad

Ours didn't "line up"...hence the modification. Sure would be easier that way if it did, though. Maybe Kevin's will.

were the perches(frame) bolted to the frt two holes or the rear 2 holes. there are 3 holes on either side of the frame. the sbc should be in the rear holes when used in conjunction with the bellhousing mounting. everything should fit with the right pieces in the right places
ron

[67Dad]

Yes, to use the SM420 & associated bell housing on a V8 requires mounting in the back two holes of the frame. Alignment (I probably used the wrong wording) might have worked, BUT we've put headers on the exhaust so the Z bar wouldn't work...maybe it would with stock exhaust, but the driver rear cylinder header pipe was in the way...hence at least moving the lever arm toward the outside a couple of inches (that the linkage from there back to the clutch arm sticking out of the bell housing)

Kevin: Future consideration...some suggest when the V8 is mounted back like that, a shroud between radiator & fan becomes necessary. We'll probably add one but haven't yet. (V8 mounted on the back 2 holes sits back further than "original" V8 did, as we understand it. To put SBC in original location messes up spacing/alignment from back of engine back that must be adjusted somehow...driveshaft length, etc.)

[padresag]

there are some headers that fit I am led to believe.
the solution then is to either go for an a/trans or install a hydraulic clutch setup
ron