Don't know what tachometer to buy.

[TomC]

I know Detroit made a 6-71TI marine engine that put out 465hp @ 2500 (real horsepower, 485hp rated). Course, marine gets highest horsepower at highest rpm. Lower it down to 2100 and you're at nearly half horsepower. Marine use doesn't have any lugging, like on road, and marine has unlimited cooling. Good Luck, TomC