Safe RPM for 212 at 70MPH

I'd try to stay under 3,000 rpm, preferably 2500. That calls for about 3.50 for 3,000, and around 3.00 for 2500.

FYI

The 212 has a 5" stroke providing good torque to pull a taller gear. Mitchell Mfg used to make an Overdrive for most cars but dropped down to just building Model A & B's OD rather than compete with the much larger Company's like US Gear & Gear Vender. Perhaps the Mitchell OD Unit woud adapt to Hudson ?? Mitchell's contact number I have is 800 859 2089.



If not adaptable, I would install a Ford Rear End around 3.00 - 3.50 from an automatic. Ford has many widths, uses similar drive shaft yokes and has same 4.5 wheel bolt circle. Probably the cheapest route to go cosidering they can be bought used from $75 - $150 complete.

Here's a route suggestion - if possiblem travel on the old U S highways, the countries original interstates like U S 20, U S 30, etc. Out there in the western part of the country most of those old roads still exist and are in great condition. You can travel 60 to 70 on them and not have to worry about getting run over by an 18 wheeler who could care less who's in his way. And, lets face it, you're driving a car that was built for those roads.



Only time you really have to slow down is going thru a town - and if you plan right you can use an interstate to get around the larger towns and cities.



I've used the old routes many times in recent years - example going over to the San Antonio area I took U S 79 out of West Memphis all the way down. Speed limit in Arkansas was 65, in Texas 70. No traffic, not much of interest (but there isn't anything much of interest on an interstate either). Travel time - about 13, 14 hours. Travel time on the interstate around 11 hours - so 2, 3 hours is a price to pay for less hassle???



The only real drawback to traveling on the old roads is if you break down somewhere. For example, going out to Miles City, MT, back iin 2001 I took U S 12. Between Baker and Miles City, about 75 or so miles, there ain't nothing out there except open space. So you may have to wait a little bit for somebody to come along and help - and most likely they will.

Still beats sitting beside an interstate wondering which one of those idiots going 90 is going to run into you.



Something to think about.

Geoff C., N.Z. wrote:

MY Jet has a 4.1 rear end, and o/d, on 640.15 tyres, which gives 2000 r.p.m. @ 60 m.p.h. It will go happily at 70 m.p..h., and the 212 is only 1/4" longer stroke, so it should handle that no problem. The problem with taller gears is pulling power in the hills, and that is hwere the o/d comes into it's own, in that you can kick down to direct drive. One of our guys here used a Toyota 5 speed box, and a 3.7 rear end, on a '37 T coupe, and he finds this drives extremely well. However there is quite a bit of engineering involved. My recommendation would to try and find a genuine '47 overdrive box. I believe any of the '48-'52 transmissions will bolt right on to your bell housing, and there must be some of those still around with o/d. Incidentally, you can't just buy an o/d and stick it on to your standard transmission. the housings and shafts are specially for o'd. Good luck,

Geoff.

FYI

I sent you a PM on a Stepdown OD.