Hi guys and girls.
Another Effie nut from Australia here.
I'm just wondering if anyone has an opinion on just how much power can be put through the 4 speed out of a '79 F100? You know the one with the granny 1st gear.
I have just had a 557 built for me and have a C6 ready to be modified but was wondering if the 4 speed, or any of the newer 5 speeds would handle 7 or 800 fwhp.
Any help greatly appreciated.

 

i cant answer your question but do wana see more pics of your truck!

 

there were a couple manual trannies in these trucks. there was one guy running about 700hp through he np435 awhile back

 

There is a guy who drag raced with an NP435 (not sure how but he did) putting over 700 down.

Another truck pulls 4x4 modified with a T19 putting out near 700.

If the tranny is in good condition they (NP435/T18/T19) are darn near bomb proof.

Josh

 

Np435 is prob the strongest non race box you can buy.

 

i've only seen one blown in my entire life. hell, the one in my 77 has a crack down the side and it still goes and i beat the **** outta that truck. just packed it with some silicone until i get the time to yank it back out and swap the gears into a case that i have sitting in my parents' garage.

 

Awesome handle/screen name or whatever...if its a ****** reference. If not, ignore me and post pictures of that wild a** truck!

 

"Ya like dags?"
"Dags?"
"Ya, dags"
"Oh dogs. Yeah, I like dogs just fine." lol Great movie.

I can't attest to 700hp but I've got about 450hp/535tq and my np435 is still smooth as glass. No trouble. From the above posts it seems that they can handle it.
Your truck looks saweet! Lets see some pics!

 

Hahaha. The name is from "Dagwood Bumstead" from the old "Blondie" cartoons, cause I could eat anything and everything and stayed skinny.
Now I'm 43 I'm fat and lazy. lol.
Yeah it is definately a NP box, but I cant read the plate in the position it's sitting in.
I would like to put the 4 speed behind it if I can.
I have some picks in my gallery of the truck 'as purchased' but now its got a nice straight cab imported from the U.S and converted, has an all steel dash out of an earlier Effie, and is sitting in my driveway in 2 pak primer waiting for me to find a good painter.
I have pics but apparently were too big so will try and resize them and get them up.
When she's finished she'll be air bagged all round, painted Flouro green, Ford colour "Lime Glaze"

 

well, if it's an np box out of an old ford p/u, then it's probably an np435. damn strong trans. it should put up with that you're wanting to throw at it. you may have to put stronger bearings in it, but i've never even tried to put a very high amount of horsepower through mine (right now i'm just kicking out 160hp, but that'll soon be bumped up to about 340hp). if it tolerates it without spinning a bearing, then let us all know because i'm sure you're not the only one who wants to put a stick behind an engine with that much power.

also, i highly recommend a dual friction clutch if your messing around with that much hp in a stock transmission.

 

Bear in mind fellas that being a 6x4 it's definately not an offroader, so it wont be highly stressed.
It'll pretty much be 'street only' and I'm only keeping it 4wd so I dont get stuck on curbs... lol
The only stress I see it getting is on the burnout pad and with the rear axle taking some weight even that wont be too bad.

 

Holy hell, I just had to post because that's one of the coolest trucks on here. The Australian trucks always seem to be pretty sweet!

If the trans is just for driving around, I think it would hold up fine, as long as you don't side step the clutch! Isn't this the transmission that was used in UPS trucks for a while? Maybe I'm wrong. If it can handle diesel torque in a loaded down box truck, I think it would work ok for just rolling around, no matter the horsepower. Clutch will need some help probably. I would personally prefer an automatic with this setup though, with a higher stall speed converter, for driveability reasons.

 

Not sure about how many HP they will handle, but I do know they are hell for stout.........I've seen em used in oilfield roustabout trucks, hot shot trucks, farm trucks and flat *** abused............Hauling in excess of 20,000 lbs combined truck trailer weight, fighting mud and snow loaded like that. The only ones I've ever seen torn up were run low on oil when they lost a seal.

 

cant say how much power they will hold, I have never seen one break! Wear out sure, but break NEVER...I have broken everything else attatched to my motor in some way shape or form atleast 10 times but not a np435.

 

with that kind of power your trans wont be your issue it will be your diffs and drive shaft/ u joints.