Spart, have you done the jetting changes yet? My carb is spot-on.
I spent weeks driving and making one change at a time an have the best tune for my engine.

I Hope it works for you!
I didn't mention that with the 4.5 power valve and 64 primary jets I can run the lightest vacume secondary spring.
With 4.10s and true tracks front and rear in 2WD it will smoke both back tires to the cords with out using the clutch. Feels like somthing is going to break!!
I've been working on building a street/ mud/ trail/ dailey driver for 10 years. I am getting close. An absolute blast to drive on or off road. And the girls, old and young, all think I have the coolest jeeeep! That's when I correct them or they don't get a ride.

IT'S A BRONCO !!!!!!

 

the weather has been snowy and icy here lately. been out playing it it a little throwing up some roost in the snow. but the roads have not been good enough to do any serious testing.

i have the lightest spring in it now. i got a power valve the other day already. maybe this weekend the roads will get cleared enough to be able to do a full throttel blast. don't worry i will keep you posted.

 

You already have the Lightning 351. Why don't you finish it like it was meant to be?

EFI...


And cure all of you carb tuning troubles forever. Imagine power under foot at all RPMs and all altitudes. Just turn the key and go.

As for tire spinning power, I could roll my 35's all day long with my 150,000 mile roller cam 5.0 and 3.50 geared Detroit Locked 9".




Jason

 

RCrawler, what year 5.0, speed density or Mass air?
I though that on a 5.8 with FI hood clearance was is a real problem.

I swore that after buying the new Holley if it didn't run I would go to fuel injection. But the new Holley does run preaty sweet once jetted.

I am switching my attention from my Bronco to my V10 superduty.
My bronco hauls *** now I want my SD to do the same.

 

It is an 87 model with speed density. I didn't have any plans for mods with this motor, so it works pretty decent.
My plan is to build a 408W with fuel injection, so I will be changing the engine control to Mass Air.

The truck 351 intake is too tall to fit under the stock hood. I've seen one of them with a hood bubble and some reworking of the upper intake accessories to make it fit. There are several aftermarket 351 intakes available based on the 5.0 Mustang design that will fit.

I ran a carb for many years with pretty good success. But after losing oil pressure and developing a knock in the original engine after stalling on a pretty steep hill, I decided to make the change.
I already had the donor car and the time to do it. If I could have done it over again, I probably would have found a later model 89-93 that already had MAF.

Jason

 

ok changed the power valve to a 4.5, jetted down to a 63 and put the stock spring back in. flat as a pancake at 3000 rpm. re jetted to 65 no change. the lighter secondary spring is about the only thing that helps. you can hear the secondary's open ??? i give up on this carb. other than being cold natured it still runs great with the double pumper. think i am going to get another new carb just don't know what i want to get. the avenger's i have been getting were off ebay and have the list # scratched off. maybe someone is selling factory defects??? guess i will find out the hard way by wasting alot of $.

would go efi but i just don't like all the stuff i have to add. like to keep it simple, never had this much trying to get a carb to run right.

thanks for the help.

 

spartamouse, Get your money back.
I had my bronco out yesterday to go on a rescue mission for 3 stuck full size pickups. I'ts the first time I have had it out in a while as it has no top. The thing runs awsome up to 5500. Starts good hot or cold. I had a great time winching and pulling those guys out of a real mess.
I got my carb from Jegs.
It doesn't have the numbers scratched off.
It came in a sealed box that had never been opened.
The truckavenger is the next best thing to fuel injection!

 

that is what i am ordering today thanks. got to pull a couple out last night myself while i was test driving.

 

put the "new" avenger on today, problem solved. left everything factory on it except put the lightest secondary spring in and it runs like a striped *** ape!! this has been a long and expensive lesson not to buy "certified" holley carbs off of ebay. 4 months, 2 avenger carbs and now i have every holley jet, spring, squirter and power valve holley makes. now i have to try and get my money back on the other avenger.
it was still all worth it today when i finally mashed the throttel on that lighning motor today and it came to life like it should. now it is one bad *** 4x4, fun to drive and play now.
thanks for the help.

 

spartamouse1

That's great to hear! I had an Edelbrock on my 351 before the Holley and there is no comparison! The rich conditions I have experienced have been while towing or continued crawling.

What other mods on your 74?

 

well you know the motor, performer intake, headman headers, ford duraspark ignition. mild built c4, 2.5" lift, quad shocks, 33" bfg mud t/a's, 3.50 posi, factory p/s and added factory power brake set, f150 disc brakes in front, twin stick, alum radiator.

last winter sent it to the body shop and had it all repainted. rhino lined the inside. re covered the seats with black and yellow inserts to match the yellow paint on the rest. don't think there is a original piece on the thing that hasn'e be replaced or we-worked. send me a e-mail and i will send a pic.

 

spartamouse1
are you saying that a stock air cleaner will work without hood work and no lift??? I hate the way a bubble looks on the hoods and I have a 351w sitting in mine that we have been working on!

 

This is one old thread! No you can not run a stock hood with a carbed 351W. The James Duff catalog gives all the info you need to do the 351 conversion.