Mopar Action On-line – Tech Questions
Jim Ransom, Phoenix AZ , 1941 Plymouth Truck 218
Speed question / concerning 3rd member –
The orginal engine is still in use (6 cyl flathead) and I need to get upto highways speeds. I found a 3rd member out of 1968 Charger (2.76non-limited slip) to get to highway speeds. Will it fit and if not -whatwill? or better yet – what am I really looking for?
1968 the casting # ends in 741
1941 casting #1141544-31
The ‘famous’ 8.75″ Mopar axle was introduced around 1957. There was also aweaker, 8.25″ ring gear version for 6-cyl cars. Older than this, and you’rereally going back a bit before my time. But I believe the splines weresmaller, etc, on the earlier axles.Therefore, you’ll probably need to do one of two things:
Adapt (narrow, etc.), and install ‘modern’ 8.75″ axle assembly (complete)
Install either a 3rd memeber of the early design, or install the correctgearset in you present carrier, with the ratio you desire.
I much prefer the first option, beacuse it gives you better brakes, and, ifyouuse a ’65-up setup, the much-easier-to-servie flanged axle design.
By the way, with the large diameter wheels and tires, and smalldisplacement, I think 2.76:1 might be a real clutch-fryer…a bit extreme.