Originally Posted by got twins ? (Post 2551054)

Hey Michael,

Thirdbird does have some very valid facts on the running characteristics of a 311 with or without trs drives.

For example there are 3 of us with 1988 311s with all three engine and drive combinations available in 1988. At one point all three were bone stock . Mine has 330s w/bravos ... the most efficient but the slowest. Kris has 365s w/bravos fastest , middle as far as efficiency and Ted had 420s w/trs the worst efficiency and slightly faster than me.

Ted's boat lifted in the rear far better and ran cleaner in the water than the other two. The transmissions sucked up alot of horsepower which in turn cost him in cruising speed and efficiency. He always had to run approx 500 to 700 more rpm to cruise with us.

That being said he upgraded his power to 585hp a side and put on 26 pitch Bravo 4 props ....... totaly different boat now .... the runs the fastest hands down and is running alot less rpms than we are at whatever cruising speed we pick.

With the bigger hps and the bigger wheels he is turning this boat runs flat in the water with no azz end sink and little to no tabs ....

Just my 2 cents for what it's worth .....

Jeff

Originally Posted by got twins ? (Post 2551054)

Thirdbird does have some very valid facts on the running characteristics of a 311 with or without trs drives.

Originally Posted by handfulz28 (Post 2552040)

I don't debate that there's a difference, just the reason for the difference. In my opinion, it's more than just a change in CG.

Were all three of those 311s turning the same props? I'm pretty sure, even with all the different combos, that the original props would be the same, 23p Mirages. If so, at least that confirms what I thought: a 454MAG/Bravo is a tad faster than a 420/TRS. :D

Originally Posted by got twins ? (Post 2552516)

I don't know anyone with the same engine / drive package as me.

Originally Posted by handfulz28 (Post 2552814)

Don't feel bad. I know of a '86 311 with 370/TRS setup. Talk about a dog. Probably why it's been rotting in my storage yard for years... :(

Originally Posted by handfulz28 (Post 2553016)

Very interesting....turns out according to BAM's website, the 370 and 454MAG share the same carb, intake, cam and heads. Rocker arms were different, valves were different. Really makes me wonder about crank vs prop HP numbers.