Change from 23 to 18 spline clutch disk

I'm lining up parts I need to swap my 833 for an PP 855. I remembered reading (I thought) that Passon would supply a 23 spline model but, they don't.

What do I need to know to get an 18 spline disk that will replace my A-body 23-spline setup? Any BB 18 spline will do? Any particular disk that's loved the BB world around?

It's been some years since I was last into my clutch. I recall something about having a 11" pressure plate and a 10.5" disk? That may have nothing to do with an 18-spline choice.

I should know this stuff. I've built a couple of motors and swapped a few 833's..but the last of that was a long time ago. I doubt my Duster has 1000 miles on it in the last 10-15 years. I'm looking to change that..but I want to keep my 4.56 gearset, too.

**Edit**
This just occurred to me: The 23 spline being a 1" shaft and the 18 spline being 1-3/16"...my TO bearing can't work, can it? Passon didn't mention that needing to change.

Thanks.

Never mind, misread your post

I don't know if anyone currently makes a 10.5 18 spline BUT I'D BET THEY DO

The 11pp/ 10.5 disk is incorrect. Some of the 440's (My 70 six bbl example) used a pp with a 10.5 BOLT PATTERN and then the outer edges of the pp mounting tabs were "scalloped" to allow room for a LARGER than 10.5 disk

These disks have been called various things through the years, including 11", 10 7/8, 10.XX and so on. THEY SUCK. I had a lot of trouble with mine not wanting to release clean

Sounds like what you want is a HP aftermarket 10.5 setup in 18 spline

Here's an old thread. You have to click on the photos to display them

I'm a little confused about this clutch.

You are correct with the throwout bearing. You will need the large T/O bearing and carrier. There are several 10.5 in, 18 spline, 1-3/16 disc and pressure plates available. What is the horsepower level you are trying to hook? Intended use? Do you have the A855 in hand?

grimreaper said:

You are correct with the throwout bearing. You will need the large T/O bearing and carrier. There are several 10.5 in, 18 spline, 1-3/16 disc and pressure plates available. What is the horsepower level you are trying to hook? Intended use? Do you have the A855 in hand?

Click to expand...

My current clutch components aren't as much the issue as I understood the 855 would work with what I have. That is turning out to not be so.

I would like to keep my McLeod PP. I spent a good deal of $$ getting it set up. I see 18 spline disks sold at 10.95" and 23 spline disks at 11". Don't see why an 18 spline disk couldn't work with my PP.

HP: Nothing extravagant at all. I've never run this motor at the track, so have no numbers for it. I put the motor together around a Hughes Engines HE3844 cam.

855 in hand? Nope. I want to get all my ducks in a row, NOT find out later that, 'Oh...you need <insert lots of cash here> of these parts, too!'

Intended use: Civilian. It's just fun to drive...and have people ask, 'What kind of car is that?'

Is there a difference in crank flange to bell face distance between LA/BB engines? I didn't think an 18 spline trans ever came in an A-body small block car.

I'd hoped to take out my 833, put in an 855. Period. It's not working out that way.

67Dart273 said:

The 11pp/ 10.5 disk is incorrect. Some of the 440's (My 70 six bbl example) used a pp with a 10.5 BOLT PATTERN and then the outer edges of the pp mounting tabs were "scalloped" to allow room for a LARGER than 10.5 disk

Click to expand...

That may well be (the incorrect part). There were two disk diameter choices available for the same PP. I chose the smaller of the two. It was purported to be a better shifting setup due to reduced inertia compared to the larger disk choice. Bracket racing was the use for the car at the time and 'better shifting' sounded good.

I found this on the web, so it must be true!

The McLeod B&B/Long pressure plate (what I have) will accept either a 10.5- or 10.95-inch disc on a common Mopar 10.5-inch B&B bolt pattern flywheel.

Click to expand...

I'd tell Jamie Passon what you need, I'm sure this is not the first time this situation has come up. If he can build a OD 4-speed, I'm sure he can come up with an 18 spline clutch disk that will work with your car.

You have pretty much answered your own questions. Get the throwout bearing assy for the 18 spline and a clutch disk that matches your pressure plate and you're good to go. Jami has the Mcloed discs on hand I believe.

small block and big block manual trans input shafts are the same length. 1968 hemi darts and cudas had 18 spline. it is possible to have a 11" pressure plate and a 10.5" clutch disc, but the 11" press plate bolt pattern would need a 143 tooth flywheel.

Call McLeod. They will make you what you need.

McLeod said a 260150 is what I need.

Marcohotrod said:

small block and big block manual trans input shafts are the same length.

Click to expand...

Thanks for that!

Unless you've been on the A855 list for six years you've probably got well over a year to get prepared....

4.56 and civilian, and a clutch....... You do realize that is a 12.04 race-track starter gear, and on the street, you will be shifting at about three carlengths out.....right?
It's the right gear to hit 60@6530 tho at the top of second. But, unless you're running a terrific traction aider, you'll be spinning all the way, nearly exactly as you would have with 3.55s.......and first gear.
TM is TM. The engine don't care if it's in the trans or in the rear or some combination of the two; 4.56 x 1.92=8.76... and 8.76/2.64=3.65, rounds to 3.55s So you can use second and 4.56s or first and 3.55s. Either way, you'll be spinning all the way, and at least with 3.55s you won't lose time in the shift.
Understandably, that 3844 cam won't like 3.55s all that much on the start line, but you have an adjustable "stall".
But where the 3.55s really shine is at 32mph..... With 27s, 32 =2710in second,3730 in first.
So my thought is that for a streeter something halfway in between is what you need, like a 4.56x2.64 +3.55x2.64 divide by 2=10.71 starter gear. And the answer is............... a 10.71/3.09=a3.09 low and 3.46s,rounds to 3.55s in the back.....Hyup .Those make a 3.55 x 3.09=10.97 starer gear.Your 3844 will love that, and 60 =7000 in first,5100 in second,and 2650 in direct. And maybe no 855 required. Ok so maybe a 3.23 might even work; it works in my combo.
The 3.55combo is what I run, and of all the many many combos I tried, this one can't be beat........hardly,lol. Course I'm only running a little 367 with a HE3037 cam. I ran race-track gears for a while, but I didn't like them at all.
But maybe you already figured all this out, so in that case, just put me on ignore,lol.