67' CJ Top Speed?

I see one lonely chevy pickup over there on the left about midway down the edge, and looks like a plymouth 4door wbout the same distance down on the right next to the trailer there.

on the 134's::hurrican:
They can't be all that fragile. They are industrial engines, built to run a constant speed for turning generators and welding machines. Constant speeds are harder on them than running 3500 for however long. We change speeds constantly going through the gears and running with traffic.
Iffen they ain't been rebuilt, they are all over 40 years old. Some over 60 years. I''m running a not been rebuilt engine, and I suspect others are also. Still got the original diffs and T-90/D-18 in it.
(would love for some one to give me an overdrive for my birthday- know what I mean?)
Except for the 2 1/2 inch shackles and the over curved rear springs with the larger tires and wheels this thing is stock.

Granted they ain't as fast, but then I didn't buy the Beastie to go fast.
I want to go fast, I'll crawl onto my V-Star 1100.:twisted:

 

I agree with ya, my F-Head is unrebuilt, smokes a little when I hit the throttle. Besides a little sputter from an old distributer and spark plug wires it runs pretty smooth. It is torqey as heck, I pulled out my cherokee hooked up to my father inlaws boat that got stuck in his back yard in Low range. The CJ didnt strain one bit; no lie. All stock except for the tail lights.
Im running the Fhead, not sure about the tranny, but the TC is deffinately a D18.

 

I have the same question. I need more top end speed out of the old Jeep. What differintial gears and tire size should be used to get the F-Head, T-90 up to 65-70 mph regularly? Will swapping to a V6 provide more top end speed or just more HP and torque?

 

v-6 will give more torque and hp..but that really wont change the speed. higher gears or taller tires will give more speed, but if you dont have the torque to push, you wont be able to run it. my 68 with the v-6 ran from brunswick maine to boston mass down I-95 @ 85 on 31" tires with 3.73. i dont recomend it on ross steering and i wont do it again, but it did and only turning about 3k or alittle more i guess. it would start getting warmer (radiator was 15% or so clogged) so i woulds slow down for a bit, but open it up when it cooled off.
speed is gearing vs rpm. you can have 500hp and still have 5.38's and only do 65 max (unless yer crankin 6 grand), but if you throw in gears, you can go alot faster.
so its a balance. you want 65 everyday? upgrade to a longer wheel base, switch to the newer style steering with the drag link (72 or later dana 30) and gear/motor it up. then pray you dont hit water or someone cut in front of you and cause you to roll. JMHO

 

My thoughts exactly. My V6 can go faster then I take it but my suspension is REALLY soft and I have manual brakes. I don't feel comfortable going that fast. Heck, if the highways weren't always so busy here I'd probably cruise at 60.

 

Right click, save.

I thought most people try to figure out how slow their JEEP will go.

 

lol. true that. sloo00oow...
must go sloo00oow to 4x4 (but must get there asafp to 4x4 more)

 

I WITH HIM! 225 will go way faster than I want to in my JEEP!:v6:

 

I'm not sure of the top speed of my Jeep since I question the accuracy of my speedo but I know that I can go fast enough in my Jeep to scare myself and I wasn't scared doing 130 in my Mustang. Between the Ross steering and the suspension I can scare the sh*t out of myself in the Jeep any time I'm over 45.

 

lolol...my ross steering is factory. never rebuilt. i have like 3/4 turn in my wheel before the tires start turning. that and the short wheel base and the small drums..i should by all rights be dead.
never again (until i upgrade that is)

 

I took a long road trip Sunday, in my 1963 Cj5 with the original F-head which could use its valves adjusted and with 15 inch wheels my speedometer read
40mph, and from the sound of the motor. I wouldn't run it any faster I definitely want to get 16 inch wheels. I don't actually know how fast I was going because of the difference in tires size. Maybe somebody knows what the actual speed was with 15 inch tires I cannot do the math. But I would say given the old-style brakes, 45 miles an hour would be as fast as I would go given the old engine and the small brakes and I believe this is the speed that military convoys travel at. I do not ever go on the highway. So I say it was designed for a maximum speed of 45 miles an hour. Therefore this is the maximum speed I feel safe driving at. I have a two axle trailer with brakes that fits the Jeep perfectly shoued I need to go on a hunting or campaign trip with friends. They will take my Jeep on my trailer. There were no highways prior to World War II. So 45 miles an hour was really moving along
Doug/Tucson:driving:

 

At 45 mph with 5.38 gears and 29" tall tires the motor would be running about 2800rpm, not really that fast.

 

that's approximately the way my 47 was set up many years ago. that's as comfortable as i felt. took it up to 55 once in new mexico.

my 69 v6 with saginaw ps will hit 75 at least (31" tires, 4.88 difs, 3 speed & od. but i don't feel safe over 55 or 60. 81" wheel base the narrow track is just too small.

 

I searched the archives first and did not find a definitive answer to a question that I am sure has been asked before
I have a stock 1963 Cj5 with 15 inch wheels and tires that read
P2351 759 15 105s. these are car tires.
My question is, regardless of the accuracy of my speedometer
and knowing that it is designed to have 16 inch rims and tires
what is my actual speed, if the speedometer is reading 40 miles an hour
Doug/Tucson

 

try this site

http://www.offroadexchange.com/speedo.htm

it is a conversion calculator for correcting the speedometer when changing tire size

a more complete formula is here http://www.barneymc.com/Toy_root/techneek/spedcalc.htm

 

Thanks for the links but unfortunately, they want extremely detailed information on tire size which I do not have the only information I was able to import
was old tires size 16 inch
new tires size 15 inch
indicated miles per hour, 40
and when I hit calculate it did nothing. Apparently not enough information
this must be common knowledge among Jeep owners my only other option would be to find one of those portable police radar indicators. This is how I found that my truck at 30 miles an hour on radar is actually 29 miles an hour
on the speedometer I've also used these portable radars to check the speed of my motorized bikes. I am only looking for an estimate, and I'm sure that eventually, somebody will read this post and give me a ballpark figure
thanks again, Doug

 

Just borrow a GPS from someone, they show speed pretty accurately.

 

Your original tire size was approximately 28" in diameter, your P235 75R15's are about 29" in diameter. That is a change of about 3-1/2% so at an indicated 40 mph you're actually doing 41.4 mph and at an indicated 50 mph you are actually doing 51.8 mph.
At 50 mph you are doing about 3100rpm with 5.38 gears and 29" tall tires. Hope this helps a little.

 

So the original Cj5s came with 15 inch rims and tires, not the 16 inch rims and tires that came with the military versions, is this correct. I was under the impression that all jeeps came with 16 inch rims and tires, which would increase my speed making the speedometer incorrect by quite a bit more
but if the transmission gearing was designed for 15 inch tires. I will not mess with it by adding 16 inch wheels and tires
Doug