Hi all,
I've got a 1994 F250HD with 351W/E40D 4:10 gears. The engine just burned a valve after 260K miles. I'm going to rebuild it. I'm looking to get a few more HP at low rpm and hopefully a little better MPG too. The engine is a factory roller engine.
Going with shorty headers to stock exhaust. Port matching the lower plenum to the heads. I do a lot of towing with the truck, but for the most part it's a daily driver when I'm not on the bikes.
I'm looking for some roller cam recommendations. Comp Cams seems to be a little confusing as all of the specs I've seen on their site say the cams they offer are not for OEM roller engines. Does anyone know what the OEM roller cam specs were for that year so I can make a comparison?
Thanks in advance!

 

The stock cam in this motor is pretty good with 256/266 advertised duration and 0.422/0.448" lift, for a little more area under the curve add 1.7 rockers.

If you want as much low rpm power as possible you need to ditch all of the stock exhaust and then add longtubes and a single 2.5" exhaust, shorties with stock plumbing behind it is a complete waste of your time with zero gains.

 

Thanks for the input! If you were going to change the cam anyway, which one would you go with? Is there any machine work involved in putting the 1.7 rockers on it?
The shorty's I already have, but they came to me in a barter deal I did a while back. No big deal. Any recommendations on the headers?

Thanks again!

 

Shorties are an upgrade over manifolds if the stock Y-pipe and cats are replaced with something(anything) from the aftermarket. Pacesetter longtubes are the best fitting available for these trucks but only if it has a TTB front axle, if it has a solid use the shorties.

For low rpm power the replacement cam to use is the Comp 35-512-8, but this cam with 1.6 rockers is almost identical in lift and duration to the stock cam with 1.7 rockers so you won't see much gain for the money spent.

No machine work involved in adding roller rockers as long as you get the pedestal mount version, these are available in both 1.6(stock) and 1.7 ratio for these motors.

 

Conanski
Thanks for the advice!

 

Conanski,
I've been looking for a set of long tubes to fit. The truck is a '94 F250HD E4OD 4WD 8800#GVW. I'd like to keep the truck as emissions legal as possible. It has the standard EGR tube off the front of cyl#1 tube. It doesn't have the A.I.R fittings in each cyl port, but it does have 2 gulp valves on the back of the manifold that go to the exh. manifold. I haven't been able to locate a set of shorty's with this setup, much less a set of long tubes.
Do you know of any headers that will fit or am I looking at some welding.

Thanks in advance.

 

I don't know of any headers with all the smog fittings for the HD trucks.

One way around this would be to use the 1/2 ton crossover tube that connects to ports on the back of the heads instead of at the manifolds. With this the truck would pass a visual inspection but unless you removed the plugs this part of the system wouldn't quite work right, but if the stock cats are removed there is no need for an air injection system at all so it's no big deal really.

 

What about cammin' up a 94 460? Any ideas on that?

 

Boomer... Are you quakertown pa or somewhere else.
Swapping the smog stuff isn't a big deal. Or just weld a fitting into the header tube like my long tubes have.

PA doesn't have a real visual check, but it does need to pass a sniffer on the rollers. (Certain areas anyway, Montgomery county does but from what I'm told the mountain region doesn't)

 

Thanks for your assistance! I'll keep ya posted as to what I come up with.

 

Quakertown PA

 

You're just north of me.
If you need/want smog, I can weld a bung in the exhaust for you and then just make a new hard line.
My obx stainless headers have a bung already in the #1 tube for egr hookup of the oem tube. No big deal to make a new one though.

 

UNTAMND,
I'm actually in Telford just off of Allentown Rd. near the outskirts of the bustling metropolis of Tylersport….
Most of the shorty's I've seen have the bung for the EGR. I've got a set of Flowtech shortys that have it, but I'd like to get bungs welded to the collectors on the shortys to match the 2 A.I.R pipes that attach there on the stock setup. I think this was only found on the 8800# GVW 250's.

 

We can possibly do that also. Take some pics and post them.
Shouldn't be too hard.
Are you upgrading the ypipe or at least the cats. Shortys don't gain much if you're still forcing it through an old clogged cat.

 

Well I've located a good 3" cat back system, and I was planning on having the y-pipe fabbed in 3". The only thing I need now is a cat. I haven't actually measured them but the shortys look like they have a 2 3/4" collector. That's far better than the 2" hole at the big end of the stock manifolds. I think I've seen your truck around. Does it have a plate on the front that says UNTAMND?
Do you have a shop?