1994 F350 Hot Street Pulling Truck

[gnr22]

Having already put together my '89 F350 together and having a positive experience with the PimpX unit and the Tuner Studio software, I leaped head first into another project that would not be intended for the street. I present my '94 F350 dubbed "Goliath".







Bottom end is fairly basic.
351w F4TE roller block.
Stock crank.
Stock rods.
Speed Pro hyper pistons.
ARP main studs. Nothing super fancy. Hardly any money into the bottom end, as I figured there would be some trial and error with this thing, so I didn't want to take a huge hit if the thing spits a rod out the block.
Top end is pretty stout.
Dart 200cc Iron Eagle heads (class rules dictate cast iron heads if the engine didn't come with aluminum from the factory).
Scorpion 1.6 roller rockers.
Trick Flow Track Max "Stage 3" cam.
Trick Flow Box R intake.
90mm Accufab throttle body.
48 lb/hr Accel injectors.
Originally had a Centerforce DFX clutch, but that lasted only a handful of pulls before it was down to the rivets. Now running a dual disc McLeod pulling clutch ($$$$$). Will be testing that this weekend, weather permitting.

Motor is backed by a ZF 5 speed, Borg Warner 1356, Dana 60 front and rear axles with 4.88 gears and Yukon lockers.

Thing runs pretty good. I have the rev limit set at 6500. Its definitely still making more power past this, but I fear for the longevity of the bottom end making it go higher than this. The low RPM drivability is less than stellar. I've been fighting a weird surge when driving at lower rpm, like trying to load on the trailer, or moving around the pits or the yard. Still working on getting this ironed out to the point that I don't hate it.

[Stinger]

Looks like quite the build!

[gnr22]

Had to dig these videos up from my computer.

First video is the first pull with the truck last season. Too low of a gear so it banged the limiter down the the whole track. Still was able to take home 2nd place. Second video was the last pull of the year, when the truck ate the clutch. The 2 step feature is killer for this application. No worry about holding a steady RPM while you let the clutch pedal out.

imgur.com/WbAwQox

imgur.com/XfBstD4

[Stinger]

You aren't kidding about it being on the limiter most of the pass, it's screaming!

[gnr22]

I think the limiter was only at 6000 on the first pass and 6500 on the last one. That's about as far as I'm comfortable pushing the stock rods.

[Stinger]

I don't blame you there.

[gnr22]

Slight update.

I got to use the new dual disc clutch an entire 2 times this summer. Took home a 2nd place (out of 11 trucks) and a 3rd place (out of 12 trucks). I've probably got the smallest CI motor in the whole class. Still more than happy with the PimpX. Going to make some suspension changes before next year, and maybe put together a forged 408 bottom end to take full advantage of the top end that I already have.

Talked another guy locally into buying a PimpX for his 460 powered OBS Ford and he's loving it as well.

I tried to tune the low RPM drive-ability on my truck and am having a heck of a time making it better. Not sure what's going on. The fuel load at idle is like 90%. Pushing the throttle in makes the truck go super lean like it wants to die. If you feather the throttle a bunch of times you can get it to come off of idle and then it runs great and the fuel load drops off to a normal number again. I'm thinking the throttle blade is closed too far at idle, as the IAC is also open like 40-50%. So that's my project for this week. Try to figure out what is going on. It would be nice to be able to move the truck around without revving it way up and irritating the neighbors. 

[Stinger]

Yeah, IAC should be more like 25-30% at idle so that's worth adjusting, though I don't think it's the cause of the issue. Fuel load shouldn't be that high at idle as that's the vacuum reading and that's basically no vacuum at all (depending on your altitude). Don't be afraid to post your tune and a log of the issue in the PiMPx area for us to assist/diagnose.

[gnr22]

If I don't get it figured out this week, I'll datalog and post it over there. The cam is fairly choppy and I attributed it to that but there's definitely more going on. It pulls like 8-10 inches of vacuum at idle. Almost nothing. Altitude here is low, 770' above sea level.

[Stinger]

That should be about 70 kPa (about 70% fuel load) then.

[Matt Culpepper 2300gearjammer]

This is definitely one of my favorites.

Is this the style clutch that you let the pedal out and rev to the point where counterweights swing over and get you moving?

....and Did you start it on a 2step on that second video and once it was moving let it go up to the rev limiter? I ask because it was wild you could get it calmed back down like you did in the first video. Ive been in one that started to bounce and its awful easy to let your right foot bounce along with it haha.

[gnr22]

Hi Matt. I appreciate you saying that.

In both videos, the clutch I had was the Centerforce DFX. Single disc, very grabby. When I called Centerforce, this is what was recommended to me, but it was NOT what I needed at all. I'm sure it's a great drag racing clutch, but not for truck pulling. The new one I put in before last season is a McLeod unit. It's a dual disc unit that is a hybrid between a slipper clutch, like you'd see in higher power "pro" pulling, and a conventional dual disc. The friction material is very forgiving and it relies mostly on the clamp load with RPM to get moving. I only have a couple of pulls on it from last season, but I really like it so far. If I remember, I'll see if I can find a video from last year with the new clutch and post it.

The 2nd video, yes I have a 2 Step button on the wheel that I hold in until I have the clutch pedal all the way out. It works very well to keep the launch smooth and controlled, and lets the power really come on once you get moving. Early in the season (like in the 1st video) I was still doing a lot of testing to try and figure out what the truck needed and didn't try with 2 step. It takes a cool head to be able to let the truck calm down and try to time it just right to put the power back on and keep the truck from hopping even worse. Very easy for even a seasoned driver to make mistakes like that.

[Matt Culpepper 2300gearjammer]

Wow good info thanks.

[lcdmachine]

Apr 28, 2021 13:42:00 GMT -5 gnr22 said:

Hi Matt. I appreciate you saying that.

In both videos, the clutch I had was the Centerforce DFX. Single disc, very grabby. When I called Centerforce, this is what was recommended to me, but it was NOT what I needed at all. I'm sure it's a great drag racing clutch, but not for truck pulling. The new one I put in before last season is a McLeod unit. It's a dual disc unit that is a hybrid between a slipper clutch, like you'd see in higher power "pro" pulling, and a conventional dual disc. The friction material is very forgiving and it relies mostly on the clamp load with RPM to get moving. I only have a couple of pulls on it from last season, but I really like it so far. If I remember, I'll see if I can find a video from last year with the new clutch and post it.

The 2nd video, yes I have a 2 Step button on the wheel that I hold in until I have the clutch pedal all the way out. It works very well to keep the launch smooth and controlled, and lets the power really come on once you get moving. Early in the season (like in the 1st video) I was still doing a lot of testing to try and figure out what the truck needed and didn't try with 2 step. It takes a cool head to be able to let the truck calm down and try to time it just right to put the power back on and keep the truck from hopping even worse. Very easy for even a seasoned driver to make mistakes like that.

Could you Email me i have some questions i would like to discuss with you 
[e-mail]