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Adapters

From: Mike Patterson
Email: mchr@theriver.com
Date: January 20, 2001

Comments

Daven's comments about changing to a later crank may be the easier and more cost effective way to go in the long run if you rebuild the engine prior to changing the transmission. He is also correct in that having a one off adapter custom built from scratch would be very expensive.

I am putting a 354 Hemi/833(OD) into a 57 Plymouth Plaza. As far as I know the bellhousing bolt pattern/crank overhang are the same between the poly motors and early hemis so this should apply in your case. Wilcap offers an adapter listed for 331/354/392 hemi to later Chrysler Auto and manual transmissions. I talked to one person who used this in a 4 spd application and he seems to be happy with it. They are at http://wilcap.com/

As I had the time, a pile of parts laying around and access to a macine shop, I and the machinest built the adapter I'm using. We used the stock adapter from a poly motor/powerflite as a starting point as it was the right thickness and the majority of the holes were already there. The lower legs were trimmed off and an adapter is being built to move a stock late model starter back flush with the engine block. The late model small block bellhousing Daven refers to is used.

The flywheel for this came off a 57 Ply 301 (which by the way was a 6 bolt crank flange). It was cut down to the external dimensions of a latter small block flywheel, and a later model ring gear was installed (incidentally, with all the equipment he had in his shop, my machinest used the brake lathe to turn down the flywheel). It was then redrilled for the later model pressure plate. This was the most expensive part of the project. $100 to turn the flywheel down, and have the new holes drilled for the pressure plate, new ring gear (about $35 but I'm not sure) and just to be on the safe side we had it rebalanced ($25). This setup uses stock clutch parts, to include the throw-out arm and bearing, and pilot bearing.

My Plaza was originally a 6 cly Powerflite car and I am using the Pedals and clutch linkage from a 57 plaza 301/stick car. As I haven't got to the point of putting the engine and transmission in yet, I don't know what modifications to the clutch linkage will be necessary.

A couple of other thoughts on your swap:

I believe your emergency brake is located on the back of the transmission, most later model 833s are not easily adapted to a rear brake drum. To retain emergency brakes you may want to also go to a later rearend.

There were at least two diffrent legnth 833s, and at least two diffrent mounting locations for the shifter, do some measuring to get what is closest for where you want the shifter.

Make sure you get the transmission yolk, shifter and shift linkage when you buy the tranny if possible. You will likely have to change drive shafts, as the yolk for the transmission will be a slip joint instead of a trunion. If your patient, you can usually find a correct legnth Chrysler drive shaft with some searching. If you run into a case where you have a mismatch in u-joint size i.e. small joint drive shaft lage joint yolk NAPA sells a conversion joint (I don't have the part number handy, but it was used on some mid-late 70s full size Dodge vans).

Depending on where the shifter comes thru the floor (especially if it's offset to the left very far), you may want to graft the shifter hump from a donner 4spd car to your drive shaft tunnel.

Good luck with what ever direction you decide to go.

 


Last changed: May 04, 2010