Just wondering if the toploader 4 speeds would bolt up to my bell housing on the back of my 390fe in my 1968 f250. Don't worry the NP will be used in another project I have but my f250 is my daily driver and I would like to be able to use all 4 gears as I drive town alot and don't really tow or carry heavy stuff with her anymore.

 

Realistically, WHY? It won't save you any gas as it has a 1.1 along with the NP-435. Unless you drive around in 1st a lot.
NP_435 ratios NP435E (Ford)6.68 3.34 1.74 1.00 8.26
oploader 4 speed - Close1st2nd3rd4thRatio 2.32 1.69 1.29 1.00 Tooth Count32282523Counter Gear Tooth Count15182125
Toploader 4 speed - Wide1st2nd3rd4thRatio 2.78 1.93 1.36 1.00 Tooth Count32312523Counter Gear Tooth Count15212430
Best for the time and money is a 5 speed OD using a NVG 4500, or a cheaper alternative is using an FE adapter from Berndtsen's with a SBF ZF-5.

 

would I need and adapter or new bell housing to use the NVG 4500?

 

Yes, you would need a new bellhousing, but you can still use a mechanical clutch. Or you can get a TKO from Modern Drivelines which is a heavy duty OD car trans. Or a T-5? Is your 250 2wd, or 4wd? What is your gear ratio?

 

2x on a TKO... no adapter needed if ya spec a short shaft from Modern Driveline. Then it's a bolt-on. Super easy.

 

I did this swap thinking the toploader would be strong enough and OD would save me some fuel. Turns out it didn't save me any fuel and the toploader isn't anywhere strong enough. Swapped the NP435 back in. A ZF5/6 would be strong enough but require custom driveshafts and relocation of the cross member.

 

Whats the opinion on towing with a toploader? Obviously back in the day they did it. For an inexpensive transmission swap, what 5 speed is preferred. Im not looking for a clunky nv4500 to shift either. Would a mustang t-5 hold up to a 350hp 302? Can I tow 4500 pounds and not worry about breaking it? What TKO do people run?

Thanks

 

A toploader would survive. I've drag raced mine for 30 yrs in a '69 F100 with 428CJ. They are a very stout transmission. I used to tow my 4600# wagon on a #1200 trailer behind my '70 F100 with 302/toploader. No problem.

I would NOT use a T5, especially if you thought to use OD while towing. It would not survive. OD is a very weak set up in those boxes.

 

Thats kind of what I was thinking, Freightrain. I would rather throw a $1000 toploader in, than a $3000 TKO. That extra money is whats going to pay for heads/cam/intake/exhaust. Im setting this truck up to be a nice daily driver that I can pull a car trailer/car on if need be. Eventually i might go to a 5 speed, or if the toploader works out, I would find a GV unit for OD and put a steeper rear gear in for a little better driveability.

Freightrain, whats your opinion on the 302 vs 351. Do you think it would be worth it in the long run to go 351? Im not looking for crazy power, but would rather have greater mpg. HP goal is around 350ish.

 

More CI is always better. My lil 302 drug my race car around for a few years til I upgraded to F350. Wasn't the fastest thing around, but got me there. It did have 4.10 gears. Back in the 90's, gas was still under a buck so mileage wasn't such a concern back then. If you have the 302, get a 347 crank kit for it? Those cheap stroker kits will work fine for you. Only when you start turning them over 6K do they start to split the stock 302 blocks. Even one for 351 can get you 390+ CI. All depends on what you want.

Sadly, I used to buy toploaders for $100 all day. Today they are $1000 with a paint job rebuild. Ugh.

 

A TKO-500 or -600.

 

Mostly im going for budgetary optimization. I can keep my 302, find some used heads, new cam, intake, exhaust, and be ready for EFI. I potentially could also do the same thing to a 351, but is it worth it mpg and power wise? If i had the money i would buy a half decent shortblock, but i would rather spend the money on some decent heads now, and put more of that shortblock money towards EFI. Also, i really dont plan to race this truck.

I wish i had the money! Currently the plan is to leave the rear gears, as is for mileage optimization with a 1:1 final gear. Eventually I'll do an overdrive and some steeper rear gears. Is there another transmission that could be had cheap that would hold up for a little while? Something i could do some light towing with if need be? Im not to terribly interested in doing an NV4500.

 

No matter what you do, you'll be hard pressed to get 10 mpg on a good day with just city driving. Buy a beater with a heater that gets 40 mpg and leave the truck alone?

 

 

D0TZ-7505-A (replaced C5TZ-7506-B) .. Bell Housing / Marked: C5TA-7505-B / Obsolete

1965/66 F100/250 2WD 352; 1966 F100 4WD 352; 1967 F100/250 2WD/4WD & F350 352; 1968/76 F100/250 2WD/4WD & F350 360/390.