Can a four speed transmission be installed in place of a three speed in a 1970 F100 with a 302 with a "low hump" floor?

 

Scott,
Yup (I think. See below). I replaced the 3 speed "toploader" in my 68 F100 with a 4 speed Toploader. I am not sure if my 68 had a low- or high-rise hump, but it did NOT have the bolt-on hump cover that my 72 F100 has, and my 68's hump looked like a low-rise hump (compared to my 72s hump). The 4 speed Toploader isn't bigger (at least height and girth-wise) than the 3 speed (it is longer).
Ohio Bill
1972 F100 360 4v 4 speed
1968 Torino GT 429 4v 5 speed

 

When you say toplader do you mean coulmn shift or on the floor?
Can i put a 4 speed with an overdrive and a floor mounted shifter in my truck?

 

Scott,
I've never seen a column shift four speed, so you would have to use a floor shifter. You have a couple of options if you want a four or five speed tranny. Here are some of them (I'm assuming your truck is 2wd).
1. You can swap in a Toploader 4 speed. It's basically a bulletproof car tranny (thus 1st gear isn't a granny gear, and 4th is 1:1 like 3rd in your current 3 speed). You will have to find a driveshaft yoke (since your 3 speed probably bolts to the tail of the 3 speed), get your driveshaft shortened (4 speed Toploader is longer than the 3 speed), and perhaps a new speedo cable (depends on the type extension housing your Toploader has and where the speedo hole is). And of course you'll need a shifter and to cut a hole in the floor. Toploaders are pricey, but indestructible and retain a high resale value. I've run one in my Ford trucks for 8 years without any trouble.
2. There were variants of the Toploader called the 3+1 (or Mexican) Toploader (some are called SMOD or SROD). Like your 3 speed, 3rd is 1:1, but 4th is an overdrive gear. Some have internal (hence SROD) shifters, some external. Used in Ford trucks and vans during the latter 70s and 1980s. These are not considered to be bulletproof but would probably hold up fine behind your 302.
3. If you prefer a 4 speed truck tranny (with granny gear 1st) find a T18, T19, or NP435. All three have granny-gear 1st, and 1:1 4th gear. Good if you do towing.
4. Finally, you could look into installing a T5 (5 speed car tranny. Used in Mustang GTs during the late 80s/early 90s. Easy to find). Fourth gear is 1:1, 5th is overdrive (.68:1?). Many places make kits to install these in 1960's era mustangs (bellhousings, etc), so you should be able to drop one into your truck with a little work.
Check out the following links for more info.
http://www.motivegear.com/tech_info/...nny_guide.html
http://mercurycapri.com/technical/tr.../toplinfo.html
http://www.4speedtoploaders.com/
Hope this helps...
Ohio Bill

 

Just FYI, the term "toploader" refers to where you drop the gears in when rebuilding, nothing to do with how it is shifted.

I have seen only one column shift 4-speed and it was in a 1965 (or thereabouts) Ford Econoline van.

 

Thanks guys your info has been extreamly helpful, especially those web pages Bill. Thanks again!