i have a 69 roadrunner w/ a 383 4 barrel, will unleaded hurt the engine? is there a fix?

Question

i`m pretty sure it was meant to run on leaded

Answer 1

if the motor origanally ran on leaded and your going to run it on unleaded. you are going to need to do a valve job on the motor. you must put in hardend valves and valve seats otherwise you will burn them up. but if the engine was not built to run on leaded then you are fine. good luck, and thats a great car. my father owned a 70 road runner with a 383 and a 4 speed.

Answer 2

It Will run just fine I had a 1970 an drove it for over ten years before i sold it I had to use the middle grade gas to keep it from knocking Wal-mart sells a product you add to your tank a lead substitute most auto parts store sell it also I used it a couple of times
I have done more valve jobs on newer cars than older one like yours I worked in a machine shop for about 6 years so keep driving ad have a good time doing it

Answer 3

no but it may knock
the lead was to help the valves
I have a 67 Mustang it runs fine on high test
and my motor is original except replaced carb(old one wore out)
these old cars were desighned for unleaded but run fine with regular gas plus mixing leadin by hand would be a pain
the realy old cars 40s can even use unleaded though some may need harder valves put in
if your car is mint go ahead and mix lead if you want other wise it is just trouble plus finding a place that sells the additive

Answer 4

Actually, the lead was used to boost the octane rating needed for higher compression engines to reduce engine knock, or "pinging".
True, it did assist in upper cylinder lubrication, ie. valves and valve seats wear, but not significantly.

I had a 1966 Chev. Elcamino with the 327 and had no problems with it running on unleaded.

The one thing that was an issue was the fuel lines tended to dry out and crack. So you may want to replace the fuel lines.

Other than that, drive on......Oh, use 91 octane too.

Answer 5

Un-leaded gas can burn the valves in an older engine. The older engines were not made with the high temp. materials the hotter burning un-leaded fuels require.

Answer 6

you can get an additive to put in with your gas at most auto parts places-it does the same job as the leaded gas-i owned a 1951 ford pu with a flathead v 8 for years-had no problems

Answer 7

You don't have much choice best run premium?There are additives for the different fuels.