Cruising at 70 mph! (1 Viewer)

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Joined
Oct 27, 2012
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Location
ATLANTA, GA
I took my 74 on another road trip, 468 miles each way. Last time I did this it was May with the weather warm and no roof or doors. This time it was 30 degrees the morning I left out so needless to say the heat never really kicked in. A week before I did an oil change and replaced the speedo gear and cable so now my speedometer is back up and running after being down a couple months. My 40 is pretty much stock with the f.5 trollhole carb 2.5" lift and 33" bfg mud. I'm curious as to who all else cruises around 70 mph and is that pretty good? I had to constantly ease up to not do 75. There was no wandering all over the road. minus the tranny/tcase being loud I think the only thing I would change is going to all terrain tires to cut down some noise. I'm considering doing a refreshing of the engine(gaskets and seals),the bay, and swapping the third members to 3:70.
 
My 74 won't go more than 57-58 MPH. When engine RPM approaches 3k it vibrates so much it feels like a paint can shaker about to explode. Its happy at 55 mph. My rig is very stable and probably would feel just fine at 65 or faster, if only the engine would rev higher. It might be the engine fan, its solid with no clutch and is probably spinning closer to 4k at speed.
 
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My rig doesnt go much faster than 95kmh, 55-60mph. I have 4.10's and will be swapping to 33's in the near future.
 
Check your RPMS at that speed running 33s. You have to be up near 32-3,500. With 35s, I'm hovering around 2,700 RPMS at 65. I usually keep it around 60 mph to keep the engine noise down.

Redline is (going off memory) 4,000 for an F. I seldom go past 3,000 on the roads unless passing (with a strong tail wind and rowing those oars like a mad man).
 
Samething it does 70 effortlessly.
I have a pinion bearing going or something. It has a vibration it didn't before that only shows up about 55-60mph. So till I look at that it stays under 55. I was thinking about 3:70s as well.
 
Check your RPMS at that speed running 33s. You have to be up near 32-3,500. With 35s, I'm hovering around 2,700 RPMS at 65. I usually keep it around 60 mph to keep the engine noise down.

Redline is (going off memory) 4,000 for an F. I seldom go past 3,000 on the roads unless passing (with a strong tail wind and rowing those oars like a mad man).
Just driving around the city I stay at 2750 rpm which is around 64 65 mph. Since I was driving through pretty much flat terrain for long distances I was around 3000 to 3250. The 40 wasn't appearing to be straining or under any stress. Redline is 4K.
 
I have 3.70 gears stock in my 1980, and with 33" tires it goes 70 (on flat ground) easily, turning 2650 rpm in 4th gear.

Because of the short wheel-base, stopping distance, and noise though, 65 mph is my really comfortable highway speed. YMMV.
 
Since the 2F rebuild, carb rebuild and BOSS air bags, my '78 cruises at 75 on flats and drops to 70 on the more extreme hills.

It has 4.11 gears stock and 30" tires, so it's turning 3600-3800 rpm, at 75 mph.... no vibration, no steering problems, other than the 9.5" wide tires getting into grooves in the pavement.

I've only been hitting 75 to to test it out... I'm done with that... as @1911 said "Because of the short wheel-base, stopping distance, and noise though, 65 mph is my really comfortable highway speed. YMMV.".
 
my 82(33 and 3.7's) does that just fine, its a bit much though, 60-65 feels better. think I had it up over 80mph once, but every single steering part was new, same with suspension, tires, brakes.

our bone stock 64 fj45LV with 28" tall tires and 4:10's.......65mph is it and that's screaming IMOP, I don't know who at Toyota made the bold claim of "Will do 85mph all day" back the 60's...but he was freaking high as a kite or drank to much Saki
 
Don't forget to factor in that 33" tires increase speed by +/- 14%... 70 is really about 80. With 3.70s the speedometer will be out by about 25& if its stock. I'm now turning 2k at 50 mph, and the SBC is happy as can be starting in either 1st or second... third it gets a little cranky.
 
my 82(33 and 3.7's) does that just fine, its a bit much though, 60-65 feels better. think I had it up over 80mph once, but every single steering part was new, same with suspension, tires, brakes.

our bone stock 64 fj45LV with 28" tall tires and 4:10's.......65mph is it and that's screaming IMOP, I don't know who at Toyota made the bold claim of "Will do 85mph all day" back the 60's...but he was freaking high as a kite or drank to much Saki

They also used to have kamikaze pilots... and advertisers never overstate claims.

Mine will easily do 100 mph, but 65the max sustained i like to do.
 
My 40 will scoot down the highway at 80. My wife was following and refused to keep up. Of course, my speedo was only reading about 68-70. ;)
 
I think 3:70s are the way to go in terms of getting my rpms down not looking to speed so much after all it is a 40. Has anyone seen any 3 member swaps in the classifieds? What gears are the most desirable?
 
One of the signs of middle age is when you become more interested in how long something will last, rather than how fast it will go.

:cheers:
 
3.70s will reduce RPMs by 10%. Off road this means an increase in minimum speed by 10%.
So, depending on how you wheel, you may end up going faster than you want. For where I drive I decided to make that compromise and don't regret that choice.
 
3.70s will reduce RPMs by 10%. Off road this means an increase in minimum speed by 10%.
So, depending on how you wheel, you may end up going faster than you want.

You can get the best of both worlds with an Orion transfer case and 3.70 diffs. I actually did an H41/Orion/3.70/33" tires combo and it's nearly the perfect gearing on and off road for me. Way worth the money (to me).
 

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