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 !

 

The Edelbrock 500 is one of the more recommended carbs for the 300.
Almost all carbs need some type of tweaking to get them to run right on an engine that was never designed for them.

Was the carb new? Or did you install a used one?

Have you checked your spark plugs to see if it's running rich or lean? If it's dumping too much gas, or if it's not getting enough, it'll really feel weak.

 

Before you change anything on the carb I'd suggest you try advancing the timing. When I swapped on an Offy, Edelbrock 500, and EFI exhaust the engine ran best @~16 degrees base timing. I switched the vacuum advance from ported to manifold vacuum and that helped as well. I had the distributor recurved and it did create a lean bog at WOT; I'm hoping a bigger accelerator pump nozzle will clear that up.

Before changing the jetting try getting a set of step-up springs and go with the stiffest pair to see if that helps.

It's also worth rechecking all the vacuum connection for leaks. Do you have a vacuum gauge? How much vacuum is it pulling at idle?

 

I actually went with the lightest step up springs. It was just dumping too much gas in with stock, or any heavier. For sure play around with the timing too.

 

Hi there

Good to know the 500 Edelprock performer was the right choice !!
I was afraid it`s too big...
Bought the carb brandnew at Summit.
The sparkplugs look pretty good.Brown as they are supposed to.
Before I checked em I was sure they are black because of a too rich mix.
But I was wrong... Forgot to mention that I changed the exhaust manifold to a EFI Header,too.
I read your posting about your modification with your Bronco L6 Offy/bigger carb (was it a 500 Edelbrock too ??) some time ago and I was so excited that I just had to do
had to do the modification too.

Thanks a lot.

Enjoy your weekend,

Scotty

 

I agree about the ignition timing. I put a Clifford intake and a large 2bbl on my '82 along with EFI exhaust manifolds and a 3" exhaust system. The result: no noticeable improvement. Then I recurved the distributor, replacing the heavy spring with a much lighter one. I also advanced the initial timing to about 10 degrees BTDC.

Before the recurve - engine ran out of torque at 3000 RPM and would not spin any higher.
After the recurve - engine pulls hard to 4200 RPM and has a lot more power.

 

Duraspark_distributor_recurve_instructions_index

The stock curve is emissions oriented and not particularly performance and/or mpg oriented.

 

I agree with others that timing may be the key to your performance issue.
For the moment, try tuning the timing and your idle mixture with a vacuum gauge.

The carb that I put on mine was a 600cfm Holley.

 

You might need to adjust your air and fuel mixture.

 

Can you explain recurving the Distributer. I'm in the proscess of putting on an offy c , Holley 600, and efi manifolds. My first ford and first 300 but I'm loving it already

 

gofastforless.com


On the left, click on:

Ignition

Then:

Ignition Curve


That is a pretty good explanation of how it works.

 

Read the article behind the link I posted too.

 

Did you install a manifold heat plate?

 

Ok.Thanks ! These days I`m a bit busy... Will check the timing this wednesday also the vacuum connection for leaks. Can`t wait to see if there`s a success.

 

"Did you install a manifold heat plate?" X2 If you didn't do that you are going to be chasing your tail to no avail.