What’s interesting is (comparing same era stuff) the SMB, with its higher rod ratio and near best spark plug location still only required 35 degrees of total timing, whereas a SBC with its lower rod ratio and absolutely garbage spark plug location needed (for a 327) about 40 total, for a 350 about 42 total and a 400 needed 44 plus degrees of total timing. And those were all “quench” cylinder heads.
The upshot is even if you brought the quench down even closer than what the OEM had them you couldn’t reduce your total timing. It may require a different curve but the total was the same.
The only time I worry about quench on a SBM is if I’m worried about dome height for compression. I don’t like building low compression engines. It’s a waste of power, economy and if done correctly, they are cleaner. If I can reduce the dome height by closing the quench gap and end up with the compression ratio I want then I do it. Otherwise I get it as close as I can and send it.
I know for a fact that guys who were big advocates of tight quench are coming off that stance. They are finding power by softening the chambers and in effect reducing quench. And that’s N/A. The power adder stuff has pretty much abandoned quench all together.
There is far more to making power and reducing detonation than quench. Especially with a SBM.
