I am currently rebuilding my 5.8L 351 in my 93 F-150. I was looking for some input on some aftermarket parts. I have scoured the forum, found some good information, but would like more up to date opinions.

I primarily use my truck for towing my quads around on my trailer and going on longer trips (mostly with my quad).

I currently have these parts on it before the rebuild:
K&N Intake
Motorvation Chip
2 1/2 inch cat back with Flowmaster

Looking into:
Lunati Truck Avenger Cam
Underdrive Pulleys

Opinions on:
Bigger Intake?
Headers?
Ignition?

I am basically trying to gain drivebility, fuel economy, and power. Let me know what else you would recommend for my application. Any and all input would be appreciated.

 

The 5.8 doens't need a lot of help to produce a healthy 0-4500rpm powerband, but most of the things you have listed won't get you there and are a waste of money.

Really all the motor needs is a cam and exhaust, and by exhaust I mean a complete system including headers. You have to be careful with the cam because I'm willing to bet your truck is speed density, so many of the performance cams are not compatable. Right now one of the few that are is the Comp Cams 35-255-5, for reference the vital specs for SD compatability are less than 210deg intake duration(@0.050" lift) and a minimum of 114deg lobe seperation angle.

 

Thanks Conanski. Yes my truck is SD.

What header choice would you recommend?

As for the cam choice Here are the specs for the Lunati Truck Avenger:
<table class="overvw"><tbody><tr></tr><tr><td class="overvw-data">
</td></tr><tr><td class="overvw-labels">Basic Operating RPM Range</td><td class="overvw-midmargin">
</td><td class="overvw-data">1,500-4,500</td></tr><tr><td class="overvw-labels">Intake Duration at 050 inch Lift</td><td class="overvw-midmargin">
</td><td class="overvw-data">204</td></tr><tr><td class="overvw-labels">Exhaust Duration at 050 inch Lift</td><td class="overvw-midmargin">
</td><td class="overvw-data">216</td></tr><tr><td class="overvw-labels">Duration at 050 inch Lift</td><td class="overvw-midmargin">
</td><td class="overvw-data">204 int./216 exh.</td></tr><tr><td class="overvw-labels">Advertised Intake Duration</td><td class="overvw-midmargin">
</td><td class="overvw-data">253</td></tr><tr><td class="overvw-labels">Advertised Exhaust Duration</td><td class="overvw-midmargin">
</td><td class="overvw-data">265</td></tr><tr><td class="overvw-labels">Advertised Duration</td><td class="overvw-midmargin">
</td><td class="overvw-data">253 int./265 exh.</td></tr><tr><td class="overvw-labels">Intake Valve Lift with Factory Rocker Arm Ratio</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.456 in.</td></tr><tr><td class="overvw-labels">Exhaust Valve Lift with Factory Rocker Arm Ratio</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.484 in.</td></tr><tr><td class="overvw-labels">Valve Lift with Factory Rocker Arm Ratio</td><td class="overvw-midmargin">
</td><td class="overvw-data">0.456 int./0.484 exh. lift</td></tr><tr><td class="overvw-labels">Lobe Separation (degrees)</td><td class="overvw-midmargin">
</td><td class="overvw-data">112</td></tr></tbody></table>
From the looks of it, I am better off getting the Comp. What else would u recommend for me to do? I am doing a semi-restoration on my truck (engine/trans rebuild, and paint) so I would like to do all I can to the engine while it is out....

 

Would I able to use OE lifters with the Comp cam or do I need cam specific lifters?

 

These cams are flat tappet so you need new lifters every time, but cam and lifter packages are pretty cheap so it's not much of an added expense. That Lunati may just be compatable.. it's got less intake duration which would offset the slightly closer LSA so overall it may perform much the same, if there aren't emissions tests to worry about I'd be tempted to try it.

As for the exhaust longtubes provide the best performance gains on a truck because they boost low rpm power more than shorties, but they always require a custom exhaust, the cheaper headers fit poorly and hang too low, and stainless and ceramic coated versions can get expensive. With shorties you can use the stock Y pipe but that pretty much destroys their effectiveness so you want an aftermarket Y at the very least, but even those are easy to install, fit well and retain stock like locations for the O2sensors, EGR pipe, cat and muffler. The 5.8 doesn't need as much help with low rpm TQ as a 5.0 so a shorty system is a good option, just depends if you want to maximize towing power or not. If the truck has a little better than stock final drive ratio you can get away with shorties IMO, meaning if the tire and axle gear combo you have produces a bit more mechanical advantage than a stock(235/75-15 with 3.55's)combo.

 

There are not emissions in my state so I am fine in that area. My dilemma is that I know the Lunati Truck Avengers are good for the older 351s but not sure on my application. The Lunati w/ lifters is 80 dollars less than the Comp w/lifters. Which isn't an issue money wise, but I am just not sure if I should go with more "compatible" cam for my application. Like you said the Lunati is damn close to the Comp. And I am tempted to try it out.

My gear is 3.55 unfortunately. I am currently Running 31s, It has a 6inch on it and the 33s were cutting down tremendously on power.

What company would you recommend for headers? The only thing I would like to stay away from is completely reworking my entire exhaust system and spending a fortune....

 

Bump...

Anyone else?

 

4.10 gears would definitely help you out here, you would be back to the stock final drive ratio with 33's and actually ahead of the game with 31's, gears should not be overlooked.

Pacesetter has longtubes that fit these trucks nicely and they are available ceramic coated. The Ford stainless shorties are another good option that are less expensive than those from Gibson and the like, and Bassini and Magnaflow make Y pipes for these trucks that don't cost a forture.

 

Alright. I decided and got the Comp cam to be on the safe side. I called both Lunati and Comp tech lines. I was a little more reassured by Comp that their cam is 100% proven to work on for my application.

As for the headers... I am still kind of torn between the long and short. I know the difference between the two and the advantages of both. BUT for my application and end result? Would I notice the difference in running long tubes as opposed to the Ford Racing M-9430-T58 Shorty Headers? Would I still be better off Cutting out the Y pipe and replacing it with an aftermarket one, even if I got rid of my Cat?

My only dilemma is that my truck as all of the ERG and Air Pump crap still on it and I do not feel like going through the hassle of blocking it all off and changing the harness. So I guess I answered my own question, I have to choose the shorties.

Thanks Conanski, You have been a huge help! Very wise in your answers. I promise I only have a few more questions

 

The air injection system is easy to remove, literally disconnect all plumbing attached to the air pump and throw it away. The pump itself can stay there as an idler pulley, and all you got to do to keep the check engine light off is leave the TAB and TAD solenids electrically connected with the vacuum lines capped. The EGR should stay anyway as it helps milage, both headers I mensioned have a port for the EGR tube.

The stock Y pipe is pretty restrictive, it crimps down to under 2" at the bends and the cat sections don't flow very well compared to aftermarket cats. The front section where the two head pipes come together also has honeycomb in it so you won't see the full potential of all your work if it stays. There's no reason you can't use the catback you have now with an aftermarket Y pipe.

 

Alright. I will look into all of the air pump removal on the forum and look into doing it on my truck.

I was planning on using the cat-back I have now. I will look into the Y pipe. I would assume it 2.5" in and 2.5" out? or is it 3" out?

As for the long vs. short... What would you recommend running for my application and final goal?

 

Also, would gasket matching the head provide any benefit on these? I am not familiar with all of the 351 build tips and tricks.... I have rebuilt too many 350s..... Just want to get some input before I start rebuilding. i have the engine out and waiting for machine work, so just want to get it all figured out ASAP

 

Longtubes fit your goals better but require a custom Y pipe.. nobody makes one for these trucks.
The heads on these motors were designed for a 289 which means they are WAY smaller than they should be for this displacement. The exhaust ports in particular are tiny and any work you do to them will help, but gasket matching in general is a bad practice that doesn't help port flow, instead open up the port to the dimensins of the part it's going to mate with.. which is the exhaust headers tube in this case. The roof and walls of the ports on these heads will need the most attention with some smoothing and blending of the bowls into the port. On the intake side there's not much you can do to the heads but the lower intake can use some port matching to the heads. Do not polish the finish on the intake ports.

 

Paul let me ask you something that is somewhat tied to this thread. If say my cats were clogged and i wanted to replace my entire exhaust system Legally could i put longtubes and delete the air system as long as it has a cat that will pass the sniffer test in the system?

 

Legally passing an emissions test is district dependant, do they have visual inspections for factory emissions equipment in your area? They don't were I live and I have passed sniffer tests with my truck equipped as you describe... longtubes, aftermarket cat, no air system.