I had an idea that im not sure would be of benefit. I suppose i could bring my idea to life very easily but i thought id throw it out here.

What my idea involves is cutting the left side of the upper intake off of the 5.0/5.8 truck intake. Then remove the middle deck inside the manifold and do some porting and smoothing inside while its cut open. Then fabricate a plate to replace the section that was removed. Maybe make it to where it has six or eight small bolts so i can take it appart later if i feel like it.

Now what this will essentially do is get rid of Fords design where the air is split coming all the way from the air box. The two tubes come from the air box then go through separate throttle bodies then inside the manifold the air remains separated with a top and bottom divider. I want to remove that divider. In my mind i think it might perform close to a Holley Systemax intake but im not sure how it will effect anything like the idle or driveability. Also if it works well enough i can run a singe oval blade style TB, but for the mild set up im shooting for i think the stock TBs will work out good.

I can pick up a manifold to butcher from the local salvage yard and if it doesnt work i can always go back to stock.

What do you guys think??

 

What does the Edlebrock 5.8 truck manifold look like inside? They claim increased HP and Tq.

 

Here you go
https://www.ford-trucks.com/forums/5...ain-in-th.html

 

I've rolled this around in my head as well. If I had a bandsaw & a spare Upper, I like to chop it up just for giggles. Maybe build a whole new plenum box. Seems to be plenty of meat carve on, drill & tap for cover plate screws, etc.

Go for it.

 

I don't think the upper and lower portions of the plenum are completely seperated though, I believe there is an opening right behind the throttle bodys so the IAC can feed all cylinders. Your idea is similar to the Eddy Performer design, and the $300 Typhoon which is a Performer copy.

 

i know exactly what you are talking about Conanski, but i think thats only a small square for pressure evening. Im thinking bigger, to remove the whole divider. Also it will allow me to access the start of those runners so i can trim and smoothe them out. Possibly even add some JBweld and form a more rounded entry for better flow.

Im only in the research phase of this at the moment but i plan on getting 6" aluminum carbide burrs to work deep into the runners. Also a novel idea i had was to cover the side ive removed with a piece of Lexan or Plexi Glass that way i can admire my work later. haha


The Holley Systemax has a nearly identical lower as the stock truck intake.
http://www.americanmusclecarhardware...-Intake/Detail

The Edelbrock Performer upper looks very similar but it also has that access pannel i want
http://www.poweredbyford.com/store/i...brock/3841.jpg

Kind of far away but it was the only truck lower pic i could find
http://www.panhandleperformance.com/...e=DCP00688.jpg

 

Another idea I had was to cut the curved section of runners off the upper and weld the flange back on so that you now have a short straight section(or nearly straight) between the plenum and lower, TB is now horizontal. This would make a good low budget high rpm intake for the 5.0.. if you have a bandsaw and tig welder handy. The only catch here is you have to position the plenum so the throttle bodies clear the distributor. Considering the size of the runners on the 5.0 intake the upper doesn't really need any work for any application using the stock heads, the lower can use some port matching but that's about it. The 5.8 intake is a different story, that motor will benefit from all the intake it can get, expecially when the heads and cam are improved.

 

May I ask a newbi to EFI question? By going with a larger TB would you have to make any changes to the injectors or EEC to allow for the increased flow or capacity?

 

Changing the TB will not increase engine flow capacity.. so the answer is no.

 

Are you saying just take off the front tubes and go with a single std TB flange & leave the plenum alone? I'd pondered that too.

But I kept wanting to get around to the a side mount. How about cutting the entire plenum off at the upper end of the runners. Then box up either a rectangular or V shaped plenum/TB mount.


I did want to ask 1Fast if he's working with a 5.8 or 5.0 since the .8s are smaller & oval. Every other trapazodial runner aftermarket manifold follows the 5.0 truck lower intake's basic architecture. The 5.8's oddly enough doesn't.

I do remember at the first of the fox revolution, when the truck lower with a hand made upper was the only other option performance besides the GT-40.

 

Dude, did you see the word cut and throttle body and make a responce? As you look at the upper intake on the truck it curves to the left. If you cut those runners in the right spot and remove a good portion of that curve then weld it back together it gives a more short runner design.

Conanski, a phenolic spacer might be just the trick for that idea. Or if it still doesnt clear get a junk intake and hack the section you need and add a little in then polish the weld out so you cant tell. But then you are talking alot of work on a stock intake.

I did some calculations on circles and surface area. Twin 52mm bores are very close to a single 74mm. Even though the most common size is 75mm, 74mm is a gnat hair away from the same surface area as the stock twin TB set up. So think about that next time you are thinking of dropping $400 on a new TB. I had a 89 mustang GT and i upgraded to a 70mm, from a 55mm i think. So im definately sure the throttle body on the truck is not a restriction for a long time.

I want to get an upper and lower and see where they need work or if i can get away with just getting the casting surface off. It really seems as though Ford was not on their A game when they did the truck combo. A snorkel that sucks on the hood, tiny opening in the intake snorkel, big throttle body CFM, air warehouse of an intake manifold, choked up heads, tiny cam, restrictive exhaust. Id be willing to say with certian mods, fuel economy will benefit just because the engine isnt going to be gasping for its air.

Forgive
Our
Retarded
Designers

 

Hey guys, in keeping with the topic, I hate the look of the truck upper intake, and always wondered why they didnt make it more like the Mustangs? I always wondered if I machined an adaptor to adapt the upper from a Mustang GT intake upper to a lower on a 5.8. (cause they didnt have 5.8's in cars, as far as I know) anyway, I know it would definately look better, but what would it do for performance? I dont know if you guys ever seen the IDIT truck or not? It was a '66 F100 and has a 351W, the guy made the upper plenum out of stainless tubing and used the stock thorttle body. He polished it all up and it was cool looking. Maybe someone can find pictures of it.


Is changing the air fitler assembly an option to getting more HP out of these beasts? Like a K&N? I am interested in this subject, in modifying the upper intake for performance and looks

 

I'm interested in it, maybe it will help with the problems I am having with my truck

 

Ive always liked the look of the tubular version of the Cobra/Explorer intake. Itd be very interesting to see that style upper on the high flowing truck lower.

 

There are lots of good ideas here, but you need to keep reminding yourself what the aftermarket offers for these motors these days. The Typhoon intake above has runners almost the same size as the 5.0 truck intake and is available for both 5.0 and 5.8 motors, and you can get the whole thing(upper and lower) as seen in the pic I posted above for just over $300. The casting is nice and heavy with lots of meat in it for additional porting, the upper is reversable, and the machine work is well done, it's a great deal IMO. The exterior finish isn't to the standards of the domestic brands.. part of the reason it's so cheap, so I ground off the rough edges on my copy and had it powdercoated crinkle black.