I hear that the stock timing on our cars is set "weak". So what should I set my timing to then? The car also has a cam in it (260/260 duration, .444/.444 lift) if that makes it need any more timing advance. It is a 305 Tuned Port Injection.

 

any ideas?

 

Anything under spark retard will work. Base timing is set for hot and cold starts, more for cold, less for hot.

The ECM and Prom tables set the total spark advance, there is one main table (rpm vs load) and more minor tables based on temp or situation (highway mode, PE). The spark advance can be tailored to any recordable spot. RPM is 200 apart 400 - 4800 and load is 16 apart 32 - 208, that is 17 X 12, a bunch of different settings. Each cell can be changed by as little as .35 degrees.

 

So what should I set my base timing to?

 

Factory is 6 degrees advanced with the ESC wire disconnected.

 

Should I advance it any more with the cam in it or not?

 

Max spark advance is 45 degrees, distributor cap wire spacing (360 / 8 = 45).

Anything more then that will fire the next plug.

Any spark advance past knock is removed by ECM/Eprom.

So any advance up to these limits can be used, these are the max, not the "best" (which is an opinion).

Think about what happens when the spark is at the 45 degrees advanced BTDC. The piston is rising pushing against the burning expanding gas. The load on the bearings is increased and the engine is fighting itself to push over TDC.

Some people set the timing by watching the oil temp rise.

The trick is to have the spark to burn the mixture so the higher cylinder pressures are seen just after TDC. Every cylinder will be different and every engine too.

Squish (low quench spacing, piston to head) engines make more power closer to TDC than way advanced.

The base timing should match the spark setting in the ECM/Eprom.