hey folks i need some help & advice. i would like to put a 5 speed tranny in my 84 ford f150 it has a 351w in it. i want to know what 5 speed tranny would be best for this also it will have 400hp with 3.73 gears. can someone please help me out!!!

 

At 400hp it will need to be the ZF 5spd trans.
There are different versions, with different bellhousings - you will need one with the small block bolt pattern (not diesel or big block)

 

Absolutely right. There is another 5-speed, the M5OD, but it isn't suitable for use with that kind of horsepower.

One issue you'll have to deal with is the hydraulic clutch linkage, as the slave cylinder is cast into and is integral with the transmission. While that may not seem like an issue, the 80-86 firewall wasn't originally designed to handle the stress that the master cylinder puts on it and it can crack - eventually. So do some searching on the forum about how to reinforce the firewall.

 

So 400+ hp will tear up the top loader that came with my 300-I6, eh? I was afraid of that. The motor I built for El Guapo will put out north of 450, so it looks like I'll have to find another tranny, too.

 

Actually, to be technically correct HP doesn't tear up anything. Torque does that. But, there is a direct relationship between torque and horsepower: HP = Torque x RPM/5252.

But, it depends on how you use it and how you drive it whether or not the tranny will survive. Just because an engine can put out more torque than the tranny can handle doesn't mean that it will ever be asked to do so. And, what usually kills a transmission is shock loading - like dropping the clutch or hard acceleration when towing a load.

So, I can't say that it won't survive - only you can do that.

 

I was aware of the torque, and depending on how it's tuned the virtual dyno says it will generate about 463 ft lbs of torque and 242 hp at 2750 rpms. The torque max's out at 489 ft lbs at 4000 rpm and 480 hp at 5500 rpms.

As you pointed out, it's more about how you put the torque to it, much more than how much torque is available. Still, I'd hate to tear up a perfectly good tranny that could be used in someone else's project.

Maybe I'll shop for a Tremec TKO500 or 600. Your thoughts on that?

 

I really don't know much about the Tremecs. Why not the ZF5?

 

If you want a performance trans, the TKO is the way to go. The ZF has a low first gear, and is a fairly slow shifting truck trans. (compared to a TKO)

If you want a truck trans the ZF is the way to go.

 

Well, since this is going to be a bit of a hotrod, I was leaning toward the TKO. I want it to be driveable, but able to embarrass a camaro, or maybe even an unsuspecting corvette when the need arises.

 

ok! what is a TKO transmission? my truck is built for fun & light duty like a small load of topsoil or mulch or a few trips to lowes but no towing at all. i got another rig for that. also where would i find one at? what did they come in?

 

TKO is made by Tremec. The TKO comes as a TKO500 and TKO600 which will handle 500 and 600 ft lbs of torque respectively. They are sold by a number of vendors. You can google it, and get a bunch of info about them.

 

Just looking at the mods for the 351W I'm assuming this truck won't be as much as a work truck but more of a street rod? I understand the TKO500 has a shorter first gear than the TKO600. I'd looked at going this route and was told to go with the 600 because the gearset worked best with 3.73 - 4.10 gears. Used Tremecs sometimes pop up with low miles for really good prices. Another suggestion might be to look into G-Force Transmissions. They make a gearset/mainshaft upgrade that will go into a stock T5 case to handle 500 ft lbs and 550hp. Looks like a killer build, keep me posted!

 

Yup. I've got dream beams up front and am working to finish up the four link out back that will lower the rear end 4 inches. I have an Eaton posi to install in the rear end, and will stick with the 3.55 gears. Eventually, I start a thread on El Guapo, as I start putting it back together.

 

Nice! I'll be following it for sure.

 

A zf would be a bolt in. Those other trannies were never offered in these trucks, so you will have to figure out the shifter position and modify/cut the hole in the floor plate, figure out what shifter will be the correct height and if it will miss the seat, what clutch you will need, how you will hook the clutch up(4 speed bellhousing?) etc.

Not saying it could not be done, but it will take some figuring to get it all right. With the zf, you will set it up with all the parts from a 2wd f250/350, so everything will fit and work, and you can order clutch parts for a f250/350 with a 351w and the guy will come out with the proper part.