bglz42

I talked with MM911 yesterday... they shaved the heads, and added a HP500 manifold and still only got 513hp @5200rpm and lower trq than they started with. Could it be the stock t-bolt ignition? This motor should be making more hp, I'd think...

Vinny P

Russ,
Sorry I didnt answer you. Somehow I missed your post. Oh well, better late than never.
I found I had a reversion problem right away. I could not get the motor to idle in neutral or even idle in the no wake zones. After messing around with the carb settings I pulled the plugs. I saw small salt deposits on them. I pulled the risers off and there it was. The manifolds had a good amount of water in them. I first thought they may have cracked. I pulled them and pressure checked them. No leaks were found. So, I went for wet CMI's . While it was better, I still had a reversion problem. I found this out by luck.. When I put the headers on, I forgot to tighten one of the cool collar clamps. When I started the engine, water dripped from that joint. The next step was full dry CMI's. That solved all my reversion problems but created noise problems. I was getting pulled over by the noise police. It really was tooooo loud, even for me to take. A set of GGB extremes was the fix. They took the bite out of the noise while still keeping that sound that we all love. So far I have not been pulled over with the GGB's. No power loss at all.

Vinny

veloc410

I know this is an old post.
Couple things to consider on lobe sep.
longer stroke engines are more forgiving to tighter lobe seperation because the piston hangs at top and bottom for longer period of time then travels faster once it gets past the tangent point far enough.
Also the hieght of your exhaust headers/risers. Keep them high then angled down towards transom so water cant get back in as easy

veloc410

I know this is an old post.
Couple things to consider on lobe sep.
longer stroke engines are more forgiving to tighter lobe seperation because the piston hangs at top and bottom for longer period of time then travels faster once it gets past the tangent point far enough.
Also the hieght of your exhaust headers/risers. Keep them high then angled down towards transom so water cant get back in as easy

SB

iTrader: (1)

I disagree….stroke does not effect dwell time at tdc/bdc. Rod length does, though. A longer rod will dwell at tdc/bdc longer.

getrdunn

iTrader: (7)

Most boater biotches prefer longer stroke and rods. 😂

veloc410

yes rod length also effects it.

veloc410

The 110 will definitely outrun a 114 as long as you don't have a reversion issue. Longer duration more reversion. Also shorter advance curve on distributor to allow more advance at idle. I'm about 18 degrees at idle. More duration , more advance
ad duration of int. and exh @ .050. Divide by 4 . Subtract lobe sep. Multi ply by 2. Use as a guide line
244+256=500
500÷4=125
125-114=11
11×2 =22
this is crane 651
Here is one I'm running
237/243 with 110
comes out to 20 overlap.
I need to prof read more