'33 PC Questions

[TodFitch]

25 PSI at driving speeds is a bit low.... Owners manual says 30 PSI at 30 MPH. Mine typically shows 40PSI at 30MPH and above. Could be a gauge issue, so you can check that against a gauge that you trust to be accurate.

If you have an old engine with unknown service history then you might want to "de-rate" it as far as max RPM. But if the engine is in decent shape then it should move the car right along at 55 or 60 MPH all day with the original rear end. And if the engine is not in decent shape they you probably want to address that.

[gillette]

Excellent info, Tod, as usual.

BTW, I so appreciate what you've said on your website about some us ?younger than 45 years old? drivers, (I?m 67;) that while the engine sounds like it is REALLY working to maintain 50 MPH on the one hand, on the other, our need to resolve this so called ?problem? of high rpm?s is for us to attempt to fix what you refer to as a ?non-existent issue.? Just so you know, your words echo in my mind as I?m driving  my PC at 50 MPH, and worrying that a rod will surely find its way through the side of the block at any moment. Your site says ?. . . even though the engine and drive train [are] capable of sustained operation at above 3000 RPM. . . .? Meanwhile, that amazing little engine shows 25 pounds of oil pressure and just keeps plugging along. I guess I?m just paranoid! :D

All that said, I would like to find out more about a higher gear set for the PC rear. I think I?ll try to reach the POC advisor you mentioned. Again, thank you for sharing your knowledge. I continue to marvel at the mountain of work you expended in your excellent web site. GA

[TodFitch]

There was a pretty big change in rear end designs in 1933 and again in, I think 1937. So your range of bolt in ring and pinion gear sets is basically from 1933 through 36. The 1937 and later axles are a bit wider than the early ones and if you use one your wheels will be extending beyond the rear fenders.

Your 4.375:1 rear end was used on the early PC and the PD. Not sure about the PE. The later PCXX had a 4.11:1 rear which was pretty was the standard ratio for rear ends into the late 1940s. I have heard that there was a 3.96:1 or so rear end set that will fit your axle made in 1936 or so but I don't have all the details. If I recall correctly the fellow that told me that was Paul Curtis the POC tech advisor for 1935 models.

Don't know about your 16" whiles but the hubcap diameter is the same for the standard wire wheels from 1931 through 33 and maybe 34. As near as I can tell the 1932 PB hubcap is identical to the 1933 PC and PD hubcap.

[gillette]

I'm trying to get away from the 4:37 gear in my coupe. I have located a guy streetrodding a '41. Will a '41 P-12 rear end fit into the same place as the stock '33 PC? What is the final drive ratio of the '41? Also, have a set of 16" adjustable spoke wire wheels, (Mopar.) I am going to put radial tires on. (Don't panic, I'm keeping the original 17" wires with the bias ply tires, :D) Will the hubcaps from a '32 19" wire wheel fit the 16" wire wheels. Thanks in advance for any help. GA