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I have a 65 F100, CC, LWB, Modified 352, 3.03 on the tree, 3.50-1 9 inch and 31x10.5 tires on 15 inch wheels. It gets going just fine and will cruise the freeway for hours at 80 mph turning at 3500 rpm. (I commute in southern California and 80 is slow) I don't necessarily need to go faster, I can push it to 100 if I want, but I would like to bring the RPM.s down on the freeway to help with engine longevity and maybe save a couple bucks on guzzoline. The 2500 5 speed is way expensive conversion, the GV unit isn't much cheaper. So I was wondering if there is a two speed rear end that would fit without TOO much modification. I'm kind of doubting it but figured I'd throw it out there. Failing that, how high could I go on the rear gear ratio without losing the tire blistering acceleration I now enjoy? 3.25, 3.00, 2.75-1?
Btw, I have adjusted speed to make up for the incorrect speedo from the oversize tires.
I know we all love pictures, so here are a couple. My Unibody project. My Unibody interior before stripping it out. Custom steering wheel that I might use. My first F100 My DD, and the truck in question during the bed swap.
Thanks for looking.
The RUG & SRID transmissionso are 3sp with 4th as OD and are kind of weak.
The killer that you can't go with say a ZF5 or M5OD is the bell is part of the Trans and think different than your motor.
I am running an Advanced Adapter Range Splitter OD unit but with a NP435, it shifts like a truck not fast.
I don't remember the 3.03 Trans listed but also was not looking for it so check the site to see.
Mine was $1700 to the door +drive shaft.
Dave ----
Sure both the RUG and especially the SROD are weak, but it sounded like money is sort of an issue, not that they are necessarily cheap either. A T5 could be good too, assuming you are going for a cruiser/commuter and not a truck. The other option would be a three speed with R11 overdrive, but good luck finding all the pieces to make operate as intended.
With a 3 or 4 speed, OD or not, you have to compromise between get-up-and-go and top speed and economy. In my mind it not until you get into 5/6 speed territory where you no-longer have to compromise.
I’m about to change the Spicer 60 in my truck from stock 4:10, to something more freeway-friendly, in the range of 3.50 to 3.73, not sure exactly what is availble.
Can you not do the same with a Ford 9”, I think that’s what is in the F100? Gotta be lots easier and cheaper. I’ve only ever owned F250’s, not familiar with F100’s.
OP says he is considering a ratio change but questions the overall effect of the taller gear. He wants to stay hot off the line but be relaxed at cruise. He has 3.50s, and he might be happy with 3.0s. Unless he has a lot of hills near by with stop signs or signals....
With the 3.50 gears and 31" tires, OP should be turning only 3035 at 80 MPH. With 3.00 gears that turns to 2601.
In any event, in the long run it is probably less expensive to spin that 352 to 3100 RPM all day every day than to regear or change transmissions.
That gives me hope, Thanks. I have a 94 Dodge NV4500 with a 205 from another project that I never used after rebuilding. Time to find a tail shaft housing and call AA.
With the 3.50 gears and 31" tires, OP should be turning only 3035 at 80 MPH. With 3.00 gears that turns to 2601.
In any event, in the long run it is probably less expensive to spin that 352 to 3100 RPM all day every day than to regear or change transmissions.
according to your numbers my tach is off? I know that when my speedo says 70 I'm doing 80, confirmed with gps speedo multiple times, with the tach at 3500. At 3000 I'm at seventy..
I checked my numbers with a calculator supplied by a major tire supplier that I found here, can't remember which one, or perhaps my final drive has been changed, unbeknownst to me.
Anyhow, yes, money is always an issue.
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according to your numbers my tach is off? I know that when my speedo says 70 I'm doing 80, confirmed with gps speedo multiple times, with the tach at 3500. At 3000 I'm at seventy..
I checked my numbers with a calculator supplied by a major tire supplier that I found here, can't remember which one, or perhaps my final drive has been changed, unbeknownst to me.
Anyhow, yes, money is always an issue.
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Sorry, I seen to have fallen asleep on my keyboard last night.
I did the NV4500 swap (from the NP435 4 speed) in 2012. Love it. My inspiration was the CEET Warrior post listed above. If you are interested, I can give you a comparison between what he did and what I did, and what my costs were, part numbers, and sources. Pictures of some of the work are in my Gallery.
Opps! Guess I don't have a Gallery. There are, however, pictures of the truck's rebuild on here, and some of them deal with the NV4500 swap. I will just mention, that doing it with a truck that was already a 4 speed and has the taller transmission tunnel was easier than it would be with a truck with the shorter trans tunnel and shifting done from the column. None the less, I'm sure it could be done, and the result, having a useful truck with "granny" at one end and the peace and quiet of overdrive at the other end is well worth it.
A (Chevy-type) friend went to look at a motorhome with 74,000 km on the 454 and TH400 for $1700. The seller didn't know it had a GearVendors OD on the trans. Nice score.
Eric
The 2500 5 speed is way expensive conversion, the GV unit isn't much cheaper. .
There is an old saying, "you have to pay to play" If you want to compete with today's vehicles on the road, you need to invest in equipment used on todays vehicles. Namely an overdrive. Once you have the go power, then you need the whoa power to stop. You'll probably want disc brakes too.
10-26-2020 | 05:53 PM
