I just bought a 38 special with stock 502's
What is a good rpm to cruise at to save on gas

0 I got a 342 and I can watch it move!

Sorry, but I can't resist...

0 rpm. That is about the ONLY way you will save on gas. It is a power boat, not a blow boat.

Real answer, 35-3800 rpm seems like it is most efficient with our hull...

yep.

Mine likes to cruise at about 37-3800. I doubt it's the most efficient there, but feels good.

Did you buy the one from Grand Sport center?

Just keep the sticks to the wood and have fun......summer is too short. You'll save money all winter.

+1

That's what I thought

3500 rpm seems to work best for most BBC for cruising as well as prolonging engine longevity.
I typically cruise between 32-3500 rpm. I've been in several 38 specials and while most of the guys have driven them at 4000+ rpm, I found that that was an uncomfortable rpm for my ears and the speed didn't seem to be much better than when I was driving at 3500 rpm. I think it was about 40-45 mph @ 3500.

In my boat there is no low fuel consumption speed, but I'm sure it's due to the Holley 1050's on top of my blowers.
I've found that by staying out of the boost in the low 3000 rpm's my cruising speed isn't much less than the low 4000's with a little bit of boost but my fuel consumption is much less.
If yours has fuel injection it should hopefully do better than carb's on the fuel economy at the lower rpm's.
Congrats on your new boat, you'll find it to be a great all around performance cruiser and overnighter.
Post some pic's for us to enjoy!!!

See ya,
Kelly