Won't go 80

Frank The Plumber said:
rear gears are too large, put in a set in the low 3's, wont accelerate as well but will have a higher top end, personally I think you are a bit insane for wanting to go 80 and battle all these commuter cars on the way to work.
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Low 3's? That'll probably make it worse. See my post above. He's running an OD ****** with a non-OD rear end already. It may have been 50+ years ago, but those engineers knew how to "do the math". I think the engine doesn't have enough power to overcome the tall gearing.
 
Had the same thing with my 39 (stock) blew out the fuel line and replaced the fuel filterand pump and pump shaft. if the pump rod is worn it will limit the amount of presure (fuel).Now I'm scared to go over 75 has alot left. Flying with these cars with no chute is not advised
 
It will do more than 80, you proly need to lock the od out with those gears, should have 411's.

Most 49-51's would do 100 by speedo proly real inacurate.
 
Frank The Plumber said:
Is he talking about his diff gear or his trans over drive gear?
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He's talking about the diff gear. He's got a 3:78 standard rear with an overdrive transmission. Car runs out of oomph at 80 mph which he thinks may be fuel starvation. All else is reported to be fine.

Although it could be fuel starvation, my theory is that the car is geared too tall and there's not enough HP & torque to overcome the gearing and wind at 80 mph. Raise the HP & torque or downshift to go faster.

Am I crazy or dos this make some sense?
 
Gearing makes sense, and just locking out the OD will tell you a lot. Full throttle advance is a problem with stock distributor, and this can only be tested in a fairly complicated way. Old speedos as stated can be wildly optimistic, but that sure is not your problem. My old '48 is, according to several police officers I met as a youth, going right about 80 when it says 80. That was expensive when Mr. Radar got involved. The same speedo showed the car's top speed to be 100MPH/160KPH (Metric car), but that is pretty certainly the optimistic side showing!! In partial defense of the speedo, it was minus 37 in Vermont when I saw the needle at 160 KPH, so air density was high, but there's no doubt it was bragging...
I would say: Get a tach in there to check numbers. Try it with OD off. If no 80 happens, worry about timing and fuel pump and perhaps aircleaner.
 
The easiest way to check your speedo nowadays is with your gps. They are very accurate and most will work on the internal battery for a couple of hours. John
 
:D Problem solved !
Ardun2.jpg
 
Frank, I have the exact same gear set-up with the non-od rear end and the overdrive. I'm running stock flattie (with alum heads) with single, stock carb and stock vacuum advance dizzy. I've ran mine up to 85 a couple of times just to see if I could and still had a little more. That kind of speed scares the hell out of me in my car and I'm wayyy to old to do this. Man, I'm telling you, the fenders are clackin, my eyes are big as saucers, and my grip on the wheel is a clamp. I was actually going to take a picture of the speedometer but was afraid to turn loose of the wheel and grab the camera. Took 30 minutes for my heart to get back to normal...slim
 
You best check your hood latch. I was passing through 80 in my '50 club coupe when the hood flew up and curled itself over the roof, 50 years ago just after I graduated high school. The 'vette I was racing is still laughing.
 
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