Does anyone have the rear end gear specs? That would answer the question pretty fast you can use the rearend gearing, tire height and final drive ratio of the transmission to figure the RPM at various speeds.

Just thowing out ideas

• If the RPM is to high could an overdrive unit such as an AOD be used as a four speed automatic and actually use the overdrive portion as a gear?
• How about an overdrive unit from Gear Vendors probably a little expensive. Although the price of gas might make up for it.
• How about one of the newer transmissions from a 1 or 2 ton truck with overdrive?

 

I just sold an F-3 with 6 cyl.The fellow I sold it to is making a street rod out of it and wants to sell the engine,gas tank and seat out of it.If you have a need for any of this stuff let me know. As for as the F-6 I am working on it may be a long wheelbase F-3 when I get through with it.

 

What are the ratios, what size tires are you planning on running how far and how fast do you want to go to get there?

 

I am planning on running the 20" rims that are on it. As long as it will go 55 MPH I will be happy with that.All I really want is for it to be depenable, so if I want go out of state I can.

 

There are plenty of calculators on the web where you can plug in the tire (not wheel) diameter or circumference, rear gear ratio(s) (unless you use an OD tranny high gear is 1:1) and either engine RPM or desired speed to get the other. For cruising down the highway at 55 (realistically, if you were to cruise the interstates at 55 you'd likely be a traffic hazzard with posted speeds of 60-70 and actual average right lane speeds +10, so I'd use 65 as target cruising speed) with reasonable gas milege, engine noise/wear and comfort you'd want the engine to be turning ~ 24-2800 RPM.

 

According to the service manual, the rear end ratios are 5.83 / 8.11 for axle no. 8TH-4209M-A and 6.33 / 8.81 for # 8TH-4209M-B. Hope this helps.
Dave

 

Thanks Fellows

 

Why can't an F-6 be a daily driver? When my '53 F-800's finished, it's going to be a daily driver, and it's got a CAT V-8.

 

Oh yeah, I've got a 254 flathead six cylinder out of my '53 F-600, that I would sale with the matching tranny. I haven't had it running yet, but it looks to be in very ggod condition, and was running when parked a couple years ago.

 

Well I found a guy today that has put a 400 Ford with a C-6 in a 56 Dodge 1 1/2 ton and runs great.I folled him up the road in my Focus at 65 MPH.So I don't think I will have any problems with my 51. Many thanks to all of you who have responded to my call for help.

 

Did you ask him what rear end ratio/tire size he was running?

 

Well all I know they were 750x20 like mine.The rear end in it was a single speed, rest unknown.

 

Can you measure the diameter of one of your tires (mounted and inflated) or better yet the tread circunference?