390 oil burning ?s

[amckid6970]

The 390 in my AMX has been worked over pretty good and will only run right with 110 sonoco. I've tried octane boost with premium and 100 low lead from the airport. I've never run the cheap octane boost either, always Outlaw. I have absolutely no clue as to what's been done to the engine because I bought it the way it is now. I'll know more about what is in it when it gets freshened up this spring.

My question is what did I miss? I've backed off timing, and even changed metering rods and messed with the idle mixture on the 750 edelbrock. Could it be washing the cylinders? It has square port heads on it and a torquer intake. It runs perfect with 110 and burns oil with anything less. Could my compression be the whole reason? If so, oh well it'll get rebuilt just the way it is and I'll just have to pay more for my gas. I'm just seeing if I can fix the problem without dropping the comression.

[jeepsr4ever]

You may have a plugged PCV or you could be sucking up oil from your PCV. Disconnect the PCV vlave and run it for a little while..it may stop burning . You should maybe replace that sucker

[amckid6970]

Thank you, the thought never crossed my mind. It had been sitting for 4 years before I started driving it.

[amckid6970]

I've been told a number of things about synthetic oil and I've probably heard just as many horror stories as I have good. One that I wonder the most about is the switching to synthetic from the regular stuff causes stuff to leak and smoke because of the engine already being worn.

The reason I ask is when I switched to synthetic is when the oil burning really started. Forgive me for not mentioning this earlier, I haven't driven the car in about 8 months and when I was chatting with my dad he mentioned it as a possibility. We still plan on changing the PCV valve, shoot for the price of one I'd be stupid not to. I was just wondering what your take was on synthetic oils.