What is the top speed reached here?

[38plymouth]

What kind of RPM's are you guys turning? My stock 38 with a 3 speed is screaming at 65-70. I cruise at 50-55 at the most, any more than that and it sounds like it's going to blow apart.

[Norm's Coupe]

What kind of RPM's are you guys turning? My stock 38 with a 3 speed is screaming at 65-70. I cruise at 50-55 at the most, any more than that and it sounds like it's going to blow apart.

I've had mine up to about 60 MPH and the engine doesn't sound like its working that hard. Since I don't race it, don't have a tach in the car so no idea of how many RPM's its turning. My engine and drive train is all stock except for being bored 30 over during the rebuild and the head shaved .035, deck shaved .010.

That said, my brother in laws 38 Ford coupe with a flathead V8 sounds like its going to blow up at 40 or 45 MPH and it has the same HP as my 48 Plymouth. Maybe the 30's cars just run at higher RPM's.

[TodFitch]

What kind of RPM's are you guys turning? My stock 38 with a 3 speed is screaming at 65-70. I cruise at 50-55 at the most, any more than that and it sounds like it's going to blow apart.

I believe your 38 has a 4.11:1 rear end and 16x6.00 tires. With that it should be turning over about 3200 RPM at 65. The car should run pretty much forever at that RPM. (Assuming, that is, that your engine is actually in reasonably good condition.)

In my 1933 with its 4.375:1 rear end and the 17x5.25 tires that same RPM works out to 60 MPH. And I run at 60 MPH pretty much anytime I get on a freeway.

Our modern ears are used to the lower RPMs at speed that were introduced during the 1970s gas crisis. But just because we are not used to the sound of high revs at cruise does not mean it is harmful to the engine.

My RPM/Speed calculator is at http://www.ply33.com/Misc/speed#calc if you want to play with the numbers.

[38plymouth]

I do have the 6.00 X 16 tires and I think the gears are 4.11. I'll hook up my tach sometime and see what the RPM's are. I know when I hooked it up last week and revved the engine to 3,000 it sounded worse than my old 327 did at 6,000. The engine is in great shape and has only 43,000 original miles.

[Norm's Coupe]

38plymouth

That could be why mine doesn't sound like its working that hard. I have the 3.9 rearend in my 48 coupe.

[greg g]

I was on the interstate the other day headed for a car show. Keeping up with most of the traffic, looked down and saw 70. I backed off a bit. Just once, I saw 80 on the speedo. I was inthe center lane trying to get over to mak and exit. Every time I slowed down the guy next to me also slowed down. So I nailed it passed him and saw the speedo tough 80. That calculates to about 3900. for my set up with the 4.1 rear and 225 75 15'S puts me at 3165 @ 65 mph, Which is how we returned from North Carolina last year. I think this was a lot less taxing on the car than the stop and go an 55 to 60 on the non interstate roads. We'll see on our trip to Va in a couple weeks. No trunk full of junk this year. 376 miles.

[Plymouthy Adams]

I know my car is a tad newer 1954 Savoy but being a flathead and an automatic tranny it will cruise at 70 without effort..with pedal to spare...I am very amazed at its off-the-line pickup (will squeal rubber) and throttle roll-on acceleration again is respectful.

[Lou Earle]

I had my 54 station wagon up to 80-85 on speedo early one Sunday on a flat 5 mile blacktop road did fine but just afraid to push it anymore.

My 46 coupe with overdrive I run ( and did today ) to Macon GA and back to Dublin - at 70-80 and it runs just great. My mileage on overdrive is between 19 and 23 depending on speed - 65 it is 22-23 at 75 it is 19

[david lazarus]

Had my '38 up to 75mph, but prefer to cruise at 60mph. The 3.23 rear end helps as it is only a 3 speed box. I may tuck a small rev counter under the dash one day and go a bit harder.

But hey, I know of one Kiwi that is pretty fast at this years Indy !!!

[1949P17BC]

Thats right Monster Mopar, September in St. Louis (Gateway International), I have run my 49 the last two years in the bracket class, 19 ish 72 plus. Lets bring em all and settle it once and for all.