RPM for a 250 strait 6

[Walleyed]

Looking For the correct cruising RPM for a older chev. 250 strait 6 / 165 hp.
I have been told 28-32 with the top end being 38-42.
At 3000 she is just at the edge of staying up on plain.
Prop seems to be ok with the 38-42 ballpark.

[Boat Doc']

You're top end is correct so with your existing prop cruise will be around 32-3400. You may be able to lower that with a doel fin, trim tabs or stainless prop.

[Walleyed]

Thanks Doc.