Optimize the spark curve for a SlantSix.

I did replace the spark plugs when I got the car, they have about 1500 miles on them now. I'd have to check what type and if the ring washers are still on or not, I think I took them off.

The exhaust is the stock 1-7/8" OD pipe, I replaced the muffler with a Walker turbo style last autumn. I have a TTI 2-1/2" system waiting to go on. I did port the exhaust manifold outlet some when I put the Holley 350 on a few weeks ago.

The carburetor has #63 jets in it, mileage has been in the 14-15 range. The Holley 1920 was about the same for mileage.

I flushed the cooling system and it has never had an overheating problem. It has a new radiator, hoses, and water pump. I'm running a new 180 thermostat.

For the first several tanks of gas I ran Seafoam and / or Marvel Mystery Oil in the fuel, to try and get the combustion chambers cleaned out, if they were carboned up in the first place.

I will check the plugs and a few other things. I will get a piston stop tool from Summit Racing and check for the TDC mark accuracy.

The temperature control valve and the EGR are not connected to vacuum lines. The new carburetor has only 2 vacuum lines. One to the distributor and one to the PCV valve. Manifold vacuum goes to the power brake booster and the heater / AC control air door assembly. I thought about leaving the PCV just open to the air, as it is probably letting an oil mist into the intake, further hurting my problems.

I have tried in the past to test for vacuum leaks in the various hoses to minimize problems.