[Henry Schmidt]

Originally posted by Shuie
Henry, is the twin plug issue over rated because this is a race engine setup to run on high octane leaded race fuel or can the big bore high compression engines run on pump gas without twin ignition and fears of detonation?

Twin plug is necessary if detonation is an issue or potential issue. High compression, high dome pistons that split the chamber, lean fuel mixture (smog engine), or low octane fuel. This engine only runs 10.5 to 1 which on a 100mm stroke 74.4mm bore and has a relatively flat piston dome. We also run 110 octane fuel and a special distributor curve that puts minimum amount of advance in until after we pass 4800. This gets us past max cylinder pressure with a reduced possibility for detonation.
BTW: we don't race the engine in the same trim that got us those phenomenal hp readings.

Related Question:
How much, if any at all, does running a MSD with a bigger plug gap help to avoid detonation or the need for twin ignition?

Anything that can help burn all the fuel (complete combustion) without too much advance will help. Will a large plug gap help? I don't know.

TIA