R2.8 to Ashcroft HD R380 stumpy Conversions

rocky

Well-known member
I've driven plenty of six speeds, and honestly they don't really advance the driving experience. I found sixth as a rare to use motorway gear.
 

Uncle Douglas

Well-known member
Long shaft r380 to Cummins R2.8
7384

Uses the same bell housing as the stumpy, Chad just milled a spacer to go behind the bell housing.

Will have some cast.

Bob's your Uncle whether you choose to go with a long or short bellhousing transmission
 

Overlander

Well-known member
beautiful work Doug. this kit will be one of my first purchases for my coming build. Starting from scratch with new Ashcroft everything and no donor selected, would there be any preference between long or short?
 

Uncle Douglas

Well-known member
Let me install one and I'll let you know. Picked up the HD Mopar clutch kit and having the flywheel drilled and tapped for that this week. Hope to finish a project and ship it and get into one of these in the next week or so. Have all the parts on hand now.

If trying to decide, I'd say it depends on what floors,tunnel, and seat box are in your donor I guess. My only concern @ present is how the big slave Chad chose will fit inside the little lt77 trans tunnel. Wont know if its a concern till we have it in the truck. Not much of an issue given the multitude of options
 

brdhmltn

Well-known member
Had time tonight to look into the clutch setup. There are various 1"x 23 spline clutches from Dodge in the 70s. Found a 12" from the 75 W200, and 10.5" and 11" from the 77 Ramcharger. The standard bolts on the Cummins flywheel for "stock" clutches are at 12.5" diameter. Seems a little tight to get the 12" in there, but maybe. No local parts store has a 12" kit in stock to try. Chad mentioned the 11" HD kit from OReillys. I tracked that back to part number K1877-06HD. That crosses with K1877-06, MU5505-1B (alternate NU5551-3), NCF 1105016 at various retailers in non-HD form. There is a Duralast kit in town at an Autozone (NU5551-3) that I may go look at. I'd have to order the specific HD kit, none local.

Doug, do you know why the non HD's don't fit according to Chad? I see several different pressure plate designs across those part numbers so that's my only thought without having them hands on. But Chad posted pictures on his company facebook page that have the thickest of the plates (at outer edge)... so I'm confused. It's no big deal to stick to the one kit, but if there are options it would be good to know.

The clutch fork/slave parts all appear to be from the 96-08 Dodge Ram. That slave is huge!
 

Uncle Douglas

Well-known member
Clutch fork used is a huge billet item Chad milled pictured elsewhere in this thread.
I have the suggested K1675-03HD here, as well as the large slave. Different # than those you listed.

Have the flywheel with machinist to be drilled and tapped to correct bolt pattern. Clutch disc and pressure plate are huge, see no reason to go larger but let me know what you end up doing.
 

Uncle Douglas

Well-known member
its listed as the HD clutch for a 340 ci dodge dart amongst other muscle cars. $146 @ O'Reilly's
 
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brdhmltn

Well-known member
I found one of the 11" kits at JC Whitney for $72 after tax/shipping. Ground shipped so it will be in by the end of the week. Will let you know if it fits. For the price it was worth trying.
 

brdhmltn

Well-known member
So the JC Whitney kit was a scam. They sent me the 10 spline clutch with the wrong part number. After spending an hour on the phone with India after hours JC support, they do not have the 23 spline available even though it says in stock and I ordered the 23 spline. So wasted a week waiting on something I have to return. I ordered the MU5505-1B which is supposed to be 23 spline but they sent the MU5505-1 which is a 10 spline.

But the pressure plate is ok to check bolt patterns.

And BEHOLD, 4 of the 6 pressure plate bolts line up exactly with the Cummins flywheel bolt holes. The other two are wide open to drill in fresh steel. I only took photos of 2 on opposite sides of the flywheel.

This might have just got a lot easier. I still need to check the cover clearances inside the new bellhousing just to be sure and I haven't gotten the new fork from Quickdraw yet.

There is an HD 11 inch kit I can order from OReillys for $168 that I'll try next now that I'm confident with the bolt pattern, but there should be cheaper 11" non HD kits available from other manufacturers in the $100 to $120 range. The local autozone has a 11" non HD kit in stock from Duralast part number NU5551-3 for $137 which looks like an identical pressure plate to the kit in the photos below. I used a 1977 Dodge Ramcharger Base with 5.9L 2BBL as the cross reference vehicle, but there are a ton of places this is used. I looked for a lever style pressure plate.
 

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brdhmltn

Well-known member
its listed as the HD clutch for a 340 ci dodge dart amongst other muscle cars. $146 @ O'Reilly's
That same kit down here is $170. With the 20% off sale at O'Reillys I got the 23 spline HD 11" kit for $130 before tax. I'll get the flywheel drilled in the next few days. 4 of the 6 bolts line up still if anyone is up for using high grade M8-1.25 bolts. My pic has 8.8's I had laying around. I think I'll just have the other two drilled same and go that route. I was torn on doing this or drilling 6 M10, as the clutch holes are almost the right size for that. But smart placement of the 2 M8 holes to be drilled I was told should be good when everything is locked down.

The clutch release arm from QuickDraw showed up in the mail today. What throwout is this supposed to use? Neither of the two kits in front of me, and from the pictures, the 10.5 clutch also, fit this giant hunk of metal.
 

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brdhmltn

Well-known member
Just to update and answer my own question, Chad designed this clutch fork to work with the Stumpy Throwout Bearing that comes with the R380 stumpy. I did not have that one to try as my R380 was bounced around the plane on the way to the US and that part didn't survive the trip. I ordered another and it slides in perfectly. No picture as I didn't think to take one.
 

brdhmltn

Well-known member
You buy a bellhousing in his kit, not a flywheel. He does not keep flywheels on hand, and they would increase shipping costs if he did. He offers flywheel exchange for a higher price, where you send yours, he drills and sends it back. Chad does the milling himself for flywheel mods I think. But to save money he will just send a print. I don't know if he has the prints finished yet either. When I got mine, the final clutch config wasn't settled yet and there was no drawing to get. But that is standard for his other products as well.
 

Z.G

Well-known member
Ahhh so it's purely pressure plate mounting holes. Wasn't sure if it also mean't slave cylinder hole as well
 
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