I just installed a 1971 Chevy 307 in my kids jeep wrangler. Whatever engineer who designed a Jeep with a 2.5L 4 banger.obviously never owned one or drove one.For the life of me, I cant remember what year chevy changed to harden valve seats for unleaded fuels.I didnt pull the heads off, but could see that it is a flat top engine and probabaly 9-1 compression. I set the timing a little retarded to stop the pinging until I find out what fuel type I need to plan for.With a 1971 engine do I need to run a lead additive?
you will additionally foul up the oxygen sensors, (4) that are high priced to change. try to discover the place the stations are that sell unleaded. the european is attempting to section them out and others are following healthful. with a bit of luck you will get greater alternatives to purchase the fabulous gas. utilising the incorrect stuff is going to be an high priced headache for you.
Check to make sure you have vacuum with no leaks at the map sensor. Also make sure the three wire connector is plugged in good and the wires are intact. Some models have a rubber seal that cracks or swells and creates vacuum leak causing code. Your particular vehicle is notable for bad map sensors The map sensor is located in three places the fire wall of the engine compartment, the air cleaner(held to it with a clip), or directly to your intake (newer models) Yours is in the air cleaner or on a bracket pass side of motor i think.
It was 1973 and you can add gas additive and run regular or mid grade for best Performance Lucas makes an injector additive that will help with the valves and since it has run lead in it before the chances are it won't bother the seats anyway as it already has the lead pounded into the valve and seats already. Your biggest problem is going to be alcohol it will eat the old valve guide seals so again the lucas additive with help with that you will also have problems with the crank case ventilator valve and the carburetor float. if you get a chance to replace it do so, if it has a Metal one your ok, but the foam floats that came with them will burn the engine down when the alcohol eats the neoprene off the float, and add a fuel pump too as it to will give up the Ghost because of the alcohol and the fuel filter as well. buy new pump and filter that won't disagree with alcohol since our good government decided to make it mandatory to burn in all fuels now.
