They look similar, but how weak are the stock A units. How were the V8 rear ends upgraded from the factory, compared to the A units? Can the A units survive for street use if they are driven (not raced), like an adult driver wants them to last a long time? Any somewhat easy to do tricks to improve their strength and longevity? How much were the V8 rear ends improved from 1932 to 40 or even 48?
If you do a search you’ll find a couple threads about model A dear strength. Seems if you go through them and make sure they are put together tight they’ll do fine with most street driven traditional builds. Some early dragsters put them behind 300hp but I’m sure they got replaced often lol. seen a lot of the behind a “built” flathead with no issue.
Model A, single bearing pinion.. V8, two bearing (straddle mount) pinion. Big difference in strength.. Although as a kid I abused an AV8 with a stock A rear and never broke it.
Model B same as Model A, single pinion bearing. Most '32's used the Model B rear end even if they came with the V8. Late 1932 V8 went to the straddle mount pinion. Charlie Stephens
Isn't the axle the weak point ? If that tapered end ( key way slot) isn't kept tight enough that's where the failures occur. My dad once told me that Indy cars in the forties & fifties used model "A" ring and pinion banjo center sections.
My '29 AV8 avatar has been running a Model A rear end since it was built in 1958. 59ab flatty, '39 trans, '40 hyd brakes. Just drive with common sense. Dave
Exactly what I was thinking. Back when I was 19, I drove like an idiot…now I leave that to the soccer moms, running late for EVERYTHING!
The fastest way to "lunch" an A differential is to be stupid. like I was. Drove the car for more than two years after I bought the '29 standard coupe in 1968. Seized on the way home one night because I never checked whether it had lubricant. Spoiler alert: dry as a bone. Months earlier I shredded the cluster gear trying to power shift to second gear while drag-racing a Corvair from a stop light. Beat him on the hole shot but . . . That sort of abuse never made it back to the differential. Weakest link in the gear box that day.
My '31 roadster pickup that I had not had for very long started making a weird noise in my friends gravel driveway sounding like I was dragging a brake rod. Looked under and all was ok. Moved forward, same noise. Went home and got my truck and trailer and hauled it home. Pulled the diff plug, no oil at all! Pulled it apart and found cobwebs inside! Old guy that built it never put oil in it. I put a good set of used pinion bearings and races in it and put it back together WITH GEAR OIL! Been running it for years now with nary an issue. Dave
I learned to drive in a cut-down 1931 Model A, that left the streets after WWII for farm duty, and it is still at it. Neither my brother or I were particularly nice to it, and neither were my cousins. It has its original rear end. Show here at The Rumble at Ralph's, Ralph's Diner, Worcester, Mass.
Actually the axle roller bearings were the same from A (28) through well into V8’s (36). And the 28-36 were bigger than the later ones on the OD. The ID is the same. Hence the ease of bolting later brakes/hubs onto A rearends.
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