what speed can i run my motor at

[1931flathead]

what speed can I run my motor at and be safe 1953 ford flathead v8 with a 3 speed no overdrive with 225 75 r15 tires

[J Franklin]

Do you want to get tickets?

[1931flathead]

no just don't want to wind the motor to much just seem like 60 is it running hard

[1931flathead]

my last 1953 had a overdrive it

[J Franklin]

60-65 shouldn't cause any problems with standard road gearing and good condition engine.

[cmbrucew]

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1953 speed limit was 65 MPH in most states.
Bruce

[AnthonyG]

Kinda depends on the condition / mileage of the vehicle?

[1931flathead]

it seem just to high of rpm to me but my exhaust is just under the front seat

[Lawson Cox]

And I'll bet you have glass packs or something. LOL

[19Fordy]

For best answer you need to know your rear axle ratio and tire dia.
Then you can figure out MPH and RPM.
Here's some help to answer your question.
http://www.jalopyjournal.com/forum/t...s-best.681030/

[JSeery]

My guess would be your engine isn't capable of high enough rpms to hurt it. Most people are accustom to the sound of more modern engines and gear train. Unless you have a tach hooked up it is very difficult to judge engine rpm.

[1931flathead]

yes it has glass packs on it I'm going to put smitty" on it with tail pipes

for rear end gears
I was told
3.31 gears for a auto
3.90 gears for a 3 speed
4.10 gears for a 3 speed over drive

[1931flathead]

yes I know with the exhaust the way it is I think I will be ok with my 5spd when I get all my parts going on a small trip next weekend about 80 miles one way

[JSeery]

RPM = (GR x MPH x 336) / Tire Dia

So for a 3.90 GR RPM = (3.90 x 60 x 336) / (28) ~ 2800 rpm

Horsepower rating on a stock flathead is around 3500 rpm

RPM = (3.9 x 70 x 336) / (28) ~ 3,300 rpm

So around 75 or so would be good for a stock engine.

[tubman]

I had a stock engine in mine with 3.55 gears (no overdrive) and had no problem keeping up with traffic on a trip from Minneapolis to Chicago 25 years ago.

[1931flathead]

ok just sound worse then it is

tach is around 180.00 for one would be nice to have one but not at this time

[deucemac]

I had a '40 pickup for years. I had a bone stock '51 Merc engine in it with 3:78 gears and 235 75 15 tires. I drove it all over SoCal and occasional trips to Utah at 65 to just a little over 70 without the slightest problem. I sold it to my now ex-boyfriend in law and he showed no mercy. As far as I know, it is still running down the road.

[RalphG]

Just on a related subject, will a new tach work on my 6 volt 52 Merc? I have an old cheap tach around here somewhere (if I can find it) that worked just by a wire connected to the distributor to give the rm readout. I'm hoping it might work as well on 6 as on 12 volts.

[TJ]

Originally Posted by RalphG

Just on a related subject, will a new tach work on my 6 volt 52 Merc? I have an old cheap tach around here somewhere (if I can find it) that worked just by a wire connected to the distributor to give the rm readout. I'm hoping it might work as well on 6 as on 12 volts.

Some early tachs allowed you to change the voltage by the flip of a switch on the back.

[flatford8]

"Ex-boyfriend in law".?.?.?.?....It's easier for me to figure my RPM's than figure out what that means !........ Mark