top/average speed of stock Cj with F-134

What do you think my top speed is. my speedo dont work 1955 CJ-5 F-134. Please help I have no overdrive!

 

Not more than 55-58 under most conditions. The stock gears on most jeeps of this era are 5.38's which really revs the old 4 banger on the highway.

 

wow thats slow if what to see my jeep go to my fourm "My Cj-5 THANKs

 

My speedo has read in the 60's before and with a stock CJ5 I've never wanted to go any faster.

 

Even if you can rev high enough, you're running out of power around 60 mph. Wind resistance is a mighty barrier.

 

60 with 33 x 13.50s , its happy at 45 though.

 

I like to use this calculator to do "what ifs".

 

I once had a CJ2A with flathead engine, 5:38 gears, and 32" tires. On level ground it would run up to somewhere between 55 and 60 and just not have any more power to push that big, flat windshield through the air. It was very happy chugging along at 45 mph.

 

with 4.27 gears and 235/85/15 tires, about 60 like everyone else said unless you can draft off a truck.
The problem I had was going to 5.38 gears, yes it ran better but turned to many rpms and a rod started knocking soon after the gears were changed. Wouldn't suggest you run an F-134 over 3k for any distance and that might be pushing it.

 

It's that really long stroke it has as well that slows your RPMS down, and valve knock like you said. Overdrives are nice. Won't add to your top speed unless pushed, but will reduce the RPM's at speed, so I've heard.

 

Mines pretty happy at 3500-3700 rpm (53-55 mph per gps) when circumstances warrent. They were designed to run sustained @ 4000 rpm, according to Mil manuals and calcs from the speed placards. If mine won't do the 35-3700 rpm reliably it deserves to be shoved in a hole and buried by my tractor

 

Is an overdrive worth it for an F-134? Is there enough HP to use the OD?

 

this has been discussed before, my m38a1 with factory 5.38's has big military sticker on dash "max50mph" had 13000 miles on odmeter when i got it, with a l head installed, pulled oil pan to check every thing out, oil pickup had been destroyed my guess it was from the orignal f head, and the damage from a rod that let go.... just guess work on my part reading from 1955 chiltons automobile repair manual page#432..year1949,4x4-63,4cyl...bore4-3 1/8 stroke4 3/8 cid134.2 developed hp "bare engine"63@4000 max torque 105 ft lb @2000 rpm, keep mine in the 2500 rpm range,just over the max torque, if i hit a hill and loose 500rpm its right where it pulls the best, top speed depends alot on your gear ratio, going to up grade to 4.27's that will put me around 55 to 60 mph@ 2500,you guys getting those high rpms got bigger cahonies than me

 

I shift at 3500-3700 and rundown the road 3000-3500 for two years with no problems. These motors are not fragile. I think the majority of the ones that blow up-start knocking were on their way out due to neglect/abuse.

 

Can you help me guess my speed!

Its a 55 CJ-5 with a 3 speed no overdrive f-134 and 5.38 axlegears can ya help View attachment 21477

 

Re: Can you help me guess my speed!

55mph

 

Re: Can you help me guess my speed!

45 miles per hour cruising. In the pic 0 mph You'd be winding it out at 55 mph