Cruising RPMs 8BA

Russco

Russco

Member
Ive done alot of searching and reading but I maybe even more confused now. I'm wanting to take my 51 Vert on a road trip to Indy in a couple days, So with a stock good running 8BA non OD and 3.78 gears will 65 MPH be too much(thats about 3000RPM's cruising for 200 mile trip) your thought on this? Last week I drove it for about 50 miles at 55-60 it did fine but seems like its turning a bit hard.It doesnt smoke carries good Oil pressure and runs 170-180 temp on the road. Thanks for your input Mike
 
a little to many rpms for me, try running at 60 mph, should be turing around 2700, max h/p is reached at 3600, thats really turning the engine
 
The 39 my father had was a 60 hp, it had a 4:44 rear, it liked 65-70 on the parkway ---several times it went to V8 meets 2-300 miles away.
I put over 1000 miles on my model a at speeds of over 60, that has a 3:78 rear
 
Kurt in NJ said:
The 39 my father had was a 60 hp, it had a 4:44 rear, it liked 65-70 on the parkway ---several times it went to V8 meets 2-300 miles away.
I put over 1000 miles on my model a at speeds of over 60, that has a 3:78 rear
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And how long did those motors last. Thats pretty much top speed for a 60hp.Cant even see it with a 4.44 RE. ken ct.:)
 
My 39 Ford had 4.44 gears with 710/15 tires and it was screming at 50 55.I went to a 8" rearend with 2.78 gears and 205/70/15 and I can still make the hills and wouldn,t go any higher.
At 2000 rpms thats 55 mph, so 3000 would be about 75 mph.
18 mpg.
 
Russco said:
Ive done alot of searching and reading but I maybe even more confused now. I'm wanting to take my 51 Vert on a road trip to Indy in a couple days, So with a stock good running 8BA non OD and 3.78 gears will 65 MPH be too much(thats about 3000RPM's cruising for 200 mile trip) your thought on this? Last week I drove it for about 50 miles at 55-60 it did fine but seems like its turning a bit hard.It doesnt smoke carries good Oil pressure and runs 170-180 temp on the road. Thanks for your input Mike
Click to expand...
leave on trip one hour early drive 50 to 55 enjoy your trip live longer and 8ba will last a lot longer
 
If it's a good engine and good oil pressure and not over heating, it will make but if it was mine I'd have an o drive in it in a min. My 40 has a T-5 trans with 3:50 gears, at 60mph in OD engine turns 2000 rpm. Of coures my 276 has alot of hp. 200 mile trip, all turn pike, with 2 carbs, 24mpg. I have 4 carbs now so get twice as much mileage, lol Walt
 
That a bit strong to run that engine that hard. Cut your speed down to 50 and not over 55.Get a overdrive or a Columbia.I have a overdrive in my 33 coupe that I got several years ago and a Columbia in my 39 and love it.Only way to go even a 5 speed. Play it cool and take it easy.Think what a rebuilt will cost if you blow it.
 
Thanks for the replies so far. I have an 8" Im prepping to put in it but its not ready yet so Im stuck with the 3.78 for now I dont think a T 5 will fit due to the convert frame being different. I run my other 8BA @ 2500 without issue just wondering if 3000 is too much i know its not ideal but will it hurt it?
 
'Ever notice how nobody ever wants to directly answer the question? Forget about road speed, tire size, and gear ratio- what's the safe R.P.M. to run the engine for long periods of time? My guess is somewhere around 2800-keeping in mind that a lot of the bigger (1.5/2 ton) trucks probably ran on the high side of 3000 for thousands of miles. My '32 is geared and tired very similar to Russco's and I get a little uncomfortable when I exceed 3000 for very long but what IS the real answer?
 
This would be a great place for JWL's book. The stock rngine runs out of power at around 3200 rpm's, max torque is around 1800 RPMs The 239 engine makes about 80 HP at




































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































Good place for JWL's book. The stock 239 engine makes about 80 HP at 3000 PMs, max torque is about 2000 RPMs. This is where the engine is operating most efficently . Now If you have other than a stock cam the rpm at which the engine operates most efficiently raises, the MAX#1 is about 2400. All this depends on the condition of the engine, having raced the Flathead for many years, a goof engine should stay together at 4000 Plus as long as it has oil pressure and doesn't over heat.But it will probably ware out quicker. Buy the Book.
 
Thanks for the replies everybody.
Dale I see what you mean nobody really wants to give a number as to what a safe cruising rpm range is although I tend to agree that 3000 seems to be a bit much.
For the record this is my 51 shoebox not my coupe so the Columbia rear is out and I'm already running 15's with G78's
So at 60 MPH with my 3.78 rear gear, 26.5 tire I am at about 2850 RPM's. That to me feels like its about as hard as I should turn it for long periods. It actually gets a real smooth feel at about 57 MPH it seems like all the vibrations and harmonics come together there. so I will just leave a bit early and keep it under 60 until I can get the 8" in there.

Thanks again Mike Russell

Dale if you happen to get to the Road Rockets show Sat look me up here is a pic of my vert.
 

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Thanks for the feedback Kahuna. Right now I am running 3:31 gears with the same wheel and tire numbers. Is a little slow on the street but rpms are good on the highway.
 
If you could find a Ford/Borg Warner overdrive transmission with that sideways solenoid adapter plate (for convertible), you would be right in there rpm wise for all types of operation. I've seen where a fellow made his own operating solenoid adapter on the HAMB. It looked almost just like the convertible one and used the standard OD solenoid. The 49/53 Ford chassis manual has a drawing of one. I hear they are hard to locate these days.

Kerby
 
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