Ok so my new engine is in and we started it up and it overheats. I am in the process of flushing the system, but I had a few questions about general engine set-up. Its a 355 with vortec heads, comp cam, Holley 600 carb, edelbrock intake, non cc HEI dist...

1. I heard that if the engine is running lean/rich, there is a possibility of running hot/overheating. Mine is definitely running hot so how do you know if you are running lean/rich? How do you fix this?

2. What timing should I set it at? Right now we just had it set so it would run so that we could break it in, but im sure the timing could be off and I heard that can make you run hot. So what should we set the timing at? I had a timing light and the line on the harmonic balancer was right around 4-6 on the timing tab thats on the timing cover.

3. I heard that with an HEI dist that you shouldnt gap the plugs over .040, but vortec heads say gap them at .060. I gapped them at .040, so is that good or are those in need of adjustment? What signs would the engine show if the plugs need adjustment?

 

Roller cam or flat tappet? What kind of rings?

Gap the plugs to about .045" or so... you could go more for a miniscule increase in power, but it's not worth worrying about.

 

Flat-tappet.

What should the timing be set to? I have a feeling that ours is pretty off.

As far as fuel goes, how do you adjust lean/rich conditions?

 

For a flat tappet cam, you must follow the break-in instructions of the cam manufacturer exactly.

Mixture is adjusted by jetting and tuning the carb. Check https://www.thirdgen.org/hei for setting up the timing.

How hot is it running?

 

A brand spanking new engine is going to run quite hot during break in, because the rings and bearings are all still "snug".
You are doing the correct break-in for your flat tappet cam right??