The purpose of the proposal is to get everyone talking before the CBF meeting.
If you read it carefully you will see there is nothing that would increase HP, any more than an SST-60 with 160 lb compression.
Nothing has changed.
I believe Port matching (Blueprinting) is allowed in stock O/B racing. (That horse has already left the barn)
Any exhaust tuner cut short might give you more top end but will deplete your torque, and as Don has always said, that is a detriment, not an advantage on the race course.
The SST-60 megaphone length is designed for 8000+ RPM, no advantage having one even shorter, there fore a length rule is not necessary.
Finger ports definitely make HP, that is why they can't be added on an already looped charged engine.
Cross flow engines could use the boost (pun intended) and I believe some Mercs have power ports.
All engines should have the benefit of 1-1/4" venturi carbs, it is another limiting factor much like the 160 lb rule. Smaller carbs give better acceleration so are sometimes better.
Don't forget we still have the 160 lb rule and pump fuel which should essentially levels the HP playing field.
Any engine with compression reliefs will give a false low compression reading which is why those particular engines can have an unfair advantage, pump gas would keep that in check. If you run too much compression for a given gas, and you back the timing down to compensate, the end result is less overall HP. (Otherwise all engine builders would jack their compression at the factory level.)
Balancing, flywheels etc do not make HP, they make our engines last longer. (Reeds may be an exception)
All factory lower units came with reverse.
The custom parts are to simply facilitate finding hard to get parts.
Building a Frankenstein engine with Yami power head, Merc lower unit and Suzuki power trim makes no more HP than any other Yamaha, so why not? You can't find a short 70 Yami but you have the where-with-all to build one, fill your boots.
Dave E
#56