specgregor

hello
I have a problem ......I've a Dodge Polara 500 Convertible 1968. Just finished restoration looks beauty ,but I don't really know what kind petrol I should use----unleaded or with lead additives. Can somebody give me an answer please. It is hard to find straight answer even in Internet .I'm gonna rebuild engine in few months time then probably I will find it myself:-)

Drag Pak

When you have the cylinder heads rebuilt, you can have hardened exhaust valve seats installed and run unleaded fuel.

Although I never took it apart, I did run my stock 1970 Barracuda 383 on unleaded fuel for 50k+ miles with no noticable dilaterious effects. Including the previous owners mileage it probably had more than 70k+ miles on unleaded fuel, and a total mileage of 100k+ miles when I sold it.

specgregor

Thanks for that. My engine is exactly same 383 high performance 4 barrow holley. She is running now on u
nleaded but everything sounds fine. Thanks again

moe7404

if you can spring the bucks get sodium filled ex valves. some of chryslers industrial engines had them from the factory. along with the hardened seats you should be ok. OH and dont for get the Marvel Mystery oil in the fuel. been useing it for over 3 decades. the engine starts faster, easier on starter, battery, so on and so on. use 4 oz to 10 gal of gas. edit: i will add. before we had lead in the gas, per mid 20s the engines HAD hardened seats. go read VERY old books. you will see hardened seat on the engines. so is there an advantage of being so old?