Hello
german Ford Truck addict needs your help... SOS !!!
I had my 1982 F150,4.9 modified with the Offenhauser Dual port, Headers and a 500 Edelbrock Performer. The result is a pain in the ***... no power gain at all..
With the old 1 bbl carb it had even more power. How in the world can that be ??
My friend of the repairstation checked everything incl. ignition, carb setup,
etc.,etc. it`s ok. But when I`m driving it now it feels like 1000 lbs or more has been loaded to it... I`m very stumped Is it possible the 500 Edelbrock is to big for the 4.9 ? Or does it need another jetting ? Who has experience with a 500 Edelbrock on a 4.9 machine ? I`m very thankful for any help. Prost !

 

Jetting should typically only be done as altitude changes. As the altitude gets higher, the air loses density. When you lose air density, but retain the same amount of fuel going into the motor, it makes the motor run rich. So you would go to a smaller jet. Typically, for every 1000 feet in elevation, you want to go down one jet size. You shouldn't have to re-jet a motor based on displacement.

How does the truck actually run? Does it ping, or knock? What about going up hills? What does it do when you go wide-open-throttle?

Also, was this originally a California truck (a stretch, I know, because you said you were in Germany, but we still need to know to get an idea of what the original ignition system on your truck was, as an 82 should have Duraspark II)?

500 CFM isn't too big at all. In fact, it's almost perfect. 600 CFM is about ideal.

600 CFM carburetors are also used on 302's quite regularly, and a 302 also has a shorter stroke, which translates to less air velocity in the carburetor (I would THINK, someone needs to correct me on this if wrong).

Did you fab up a water-heated plate to mount on the underside of the intake-manifold? All intakes, no matter what motor they're on, require some form of heat. This helps the fuel vaporize when it hits the bottom of the plenum, and if the fuel isn't vaporizing (i.e., atomizing) like it should be, then you'll have running issues like bogging and lack of power.

The factory heated the intake by bolting the exhaust and intake together and using the heat from the exhaust manifold to heat the intake.

 

sonnybottomboys.de,

I suggest that you go down the page to the "Inline six" forum... those guys have done similar set-ups many times and will be glad to lend a helping hand.

You will have more power once properly set up, with the changes you have made.

 

The question about what the truck has on it, meaning ignition, is very important. I can't say about the 4.9L engines, but in the States the 5.8L and I believe the 5.0L engines came with EEC-IV engine control computers and DS-III ignitions. The computer read several inputs and had control of carb air/fuel ratio and all ignition timing.

So, if that is what you have then your computer will be UPSET because it can't control things and will have gone into "limp-home" mode, which means the ignition timing is locked to something like 10 degrees BTDC. Given that, the engine will have no power.

If that is the case then you will have to do a DS-II installation on that engine in order to get the mechanical and vacuum advances to work. Look in the stickies up front and you'll find a how-to on DS-II conversions. And, since the wiring for the EEC system was kept separate you will be able to remove all of it and the associated sensors, relays, etc.

Having said all that, do you have to meet emissions testing over there? If so, you may have a problem.

 

80 to 83 49 state 4.9's are DSII.

80 to 86 Canada emissions, I think, are all DSII.

80 and 81 California are DSII and 82 to 86 California are computerized (I THINK, never paid attention to Cali stuff since I hate computerized vehicles).

84 to 96 are all computerized.

But yeah, we need to know what ignition system you have. Photo of the distributor (factory original distributor) and the ignition module would be of great help.

 

Almost.

The F250s & 350s with either the 351W 4V HO engine or with the 460 kept their DSII setups through 1987 or 88 or somewhere around there.

 

the truck runs actually good but with poor power, especially accellerating
at low rpm. Higher rpm`s are better but not really noticeable after all the modification. No ping or knocks. Just shakin`a bit at idle... idle fuel mix and
rpm is ok.

Unfortunately I don`t know where my truck was located before I got it...
I`m the third owner since it got here 10 years ago. Got it since 5 years.

I wrote it`s a 1982, sorry wrong data, it`s a 1986 !

All the electronic and emission crab is not there anymore. IT´s almost like a 70`s engine now. I don´t know which type of ignition and distributor it is now cause it has been changed with the edelbrock/offenhauser.
All I know is that `the distributor is vacuum connected.
Will post a picture of the engine as soon as I can.

Thanks much !!!

Scotty

 

Allright ! Great ! Will do that. Thanks !!!

 

Hi there,

all the electronic stuff/ computer / emmissions-crab has been disconected and dumped cause I hate computers in cars

Yes, we have biiig emissioncontrols over here but we rednecks are lucky cause we got some redneck friends that do the testings
"I got friends in lower places where the wiskey drowns and the beer is chasing my emission problems away..."

Thanx man !

 

I was referring just the sixes, but yeah, 351's and 460's kept their carb setups through 87 until 88, when they went TBI like the other motors, as I understand it.

 

I thought they went straight to EFI?

My 1986 DD has TBI, IIRC it was used only a few years, in between carbs & multi-port EFI.

I don't think I've ever seen a truck with TBI....

 

Don't take a picture of the engine specifically, but take a picture of your ignition module, which, a 100$ bet says you've still got the EEC-IV module behind the ashtray under your dash in the cab.

Duraspark II modules need to be mounted on the inner drivers fender, and you need the DSII wiring harness. You can get the harness from a (if I remember right) 76 to 83 Ford truck. Doesn't matter what engine. Module doesn't matter either so long as it's good and it's DSII.

In other words, finish the DSII conversion on your truck. It won't be right until it's finished.

Take photos of the module, your distributor, and the way you've got things set up on the motor with the carburetor.

Here's a tip you probably didn't know: On an Offenhauser dual plane intake, the primaries of the carburetor need to be facing the valve cover and the secondaries need to be facing the passenger fender. This is so the fuel distributes right because of the way the intake was designed. On the "C" series, you can mount it any way you want because it's an open plenum. But on the DP, you definitely have to have the primaries towards the valve cover and the secondaries towards the fender.

AND, you ABSOLUTELY (MUST) heat the bottom of your intake! Some people get by with a heated carburetor spacer (from a late 60's Ford Galaxy with a 390), but it doesn't work as well. Fab up a heat-plate that you can use to heat your intake to solve your off-idle bogging.

 

Huh... I was under the impression the trucks after the feedback carbs were TBI.

So they went from computerized carbs straight to multi-port?

 

460's did for sure!

That TBI stuff is for Chevy's.

 

For what it's worth, I'm the only Ford guy in my family.

I hope I'm forgiven. I'll take my 20 lashes now.