Question From a Newbie!

Carl · Aug 10, 2006

Hey guys,
I was just wondering if you can run unleaded gas in a 1974 or earlier Bronco
since these were originally designed to run on leaded gas? Does it really make any difference. What are the drawbacks (if any) to running unleaded gas in one of these early engines?

I thought that I heard somewhere that it has something to do with the lubrication of the valves or something.

Thank You,
Carl

ponch0v · Aug 10, 2006

CarlF250 said:
Hey guys,
I was just wondering if you can run unleaded gas in a 1974 or earlier Bronco
since these were originally designed to run on leaded gas? Does it really make any difference. What are the drawbacks (if any) to running unleaded gas in one of these early engines?

I thought that I heard somewhere that it has something to do with the lubrication of the valves or something.

Thank You,
Carl

Yup lead helped lube the valves and also cushions the the valves when they were closing on the valve seat. You can get the stuff you add to the gas to help the "leaded" cars run on unleaded fuels.

Didnt '74 have to run on low lead gas. Its possible you you may have the hardened seats unleaded heads already. I could be wrong

Talked to my engine builder about redoing my heads and for the amount I drive it he said run it till it needs head work and then go for the hardened seats.

NVraider · Aug 10, 2006

don't mean to be a smart-a$$ but leaded gas was banned from use in on-the-road vehicles in 1996, looks like we don't have much of a choice.

broncnaz · Aug 10, 2006

We've ben running them for years on unleaded and as ponchOv said you could have hardened seats theres not much info on when they started installing them but I would imagine it was right around 74 about the same time catalitic converters started showing up which only used unleaded gas. just run it till it needs to be rebuilt my 73 went 177,000 miles before I decided to rebuild it and the valve seats still looked pretty good.

wildbill · Aug 11, 2006

My motor is still running on nolead and has since they took lead off. I have yet to have a problem. Its a 351W 4V 1969. I would say just go with it some day it will need a valve job and you can put in hard seats and SS valves. Good luck and have fun.%) %) %) Bill %)

;D

SaddleUp · Aug 11, 2006

Leaded fuel was banned a long time ago. Unless your EB has sat for a lot of years then it has already been run on unleaded fuel. Normally either the valves are okay or the heads have long since been gone through to make it run on it. When leaded was first banned it was a coin toss. Some had to have the heads gone through and some ran fine.

scsm76 · Aug 11, 2006

When I took a part my original 73 302 at about 160,000 the valves had sunk into the heads over an 1/8". Rebuilt it and added hard seats ran great till the piston went through the block to many ponies added though.

DebosDave'72 · Aug 11, 2006

NVraider said:
don't mean to be a smart-a$$ but leaded gas was banned from use in on-the-road vehicles in 1996, looks like we don't have much of a choice.

There are adatives that can be used in place of lead... I am wondering if that is the problem with my heads, I have been having a rich condition and low compression on a couple cylinders...

DD

Question From a Newbie!

Carl

Bronco Guru

ponch0v

Sr. Member

NVraider

Jr. Member

broncnaz

Bronco Guru

wildbill

Old Bronco Guy

SaddleUp

Bronco Guru

scsm76

Bronco Guru

DebosDave'72

Bronco Guru

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