So their called Pyrometers – thanks for the info. Could anybody recommend a good manufacturer of these for marine use? Sounds like a spot for 4 more gauges would also be necessary. I would be a little worried about drilling and tapping the exhaust manifolds for senders in fear they may crack with thermal expansion/contraction.

I would hate to ruin my 1976 VT903s over trying to save a couple grand on gas.