Yes sir you are on the money with a V-20. I have a 350 V-8 which suck's up a little more gas. Last trip out to the texas towers I used 75 gallons.
I use addition gas tank installed in my live well. Buy the way the fish move around according to the bait source so you may have to move and burn more fuel! So that leaves me taking along a extra 15 gallons that I safely tie to the deck.
Chuck is correct that a V-20 is on the edge to do a trip like that. God help me if things go to ****! I really don't want to bail with my four man viking life raft and ditch bag.:oh:

My old school 200 might get around 3 to 5 mpg, never checked but it sure varies with how you run it & how rough it is. The good reefs start around here about 30 miles out. Add in some running around out there & I've found that I should stay within 35 miles to have my 1/3 reserve on return. I've pushed it a few times, the fishing just gets better & better the farther you go & on a clear calm day it sure is tempting. I guess if all went well & you burned your reserve you could get 75 miles out, not me.

The problem is not just the fuel, its the time. 60 miles out takes 2 hours when its flat with no swell. Even if its glassy, an east swell will slow you down and it take 2.5 hrs. Leaving (the inlet) at first light gets you there at 7-730. So now you fish til noon and you have to worry is the wind going to kick up out of the south. That ride home can become a 4 hour+ ordeal if you don't pay attention. Also, it can be nice 60 miles out but the afternoon south wind along the coast here can, and often does, make it nasty for the 10 miles nearest the shore.
I always start my way in at noon( no matter how beautiful the conditions are), stopping at points along the way if the conditions are holding up. That way I'm shortening the distance that I might get caught in a wind.

Definitely build in extra time for the return trip. Never know what might happen and heaven forbid getting stuck out there after dark. I spun my prop last trip. Luckily we were just heading out and only 8 miles from the inlet. Took 1.5 hrs to limp back in. From 40 out would've taken 7 - 8 hrs or more.

just filled mine up
28.3 gallons
135miles.
lotta bay running & trolling, so that pumps the numbers some

the best part.....@$2.59 for non E

Thats almost as good as my 19 foot CAROLINA SKIFF with a 75HP HONDA on the back, nothing to be ashamed of right there.

like i said, lotta low rpm stuff, but that 150 merc 4S is amazing on fuel and torque.

WOT is around 12 gph, with 38-40 mph. if you let it the big dog will eat

I would like to share one more calculation on this subject, am still taking this beating at 69 years old!:zip:

:party:Keep on keeping on brother.

Exactly............these are little boats to go far out. Not that it can't be done by hard core guys such as Step Up, but it's a stretch.