I see said the blind man. That's going to be some kind of plumbing coming out of the bottom of that box. Are you planning on running it down between the outside of the drives and the K-planes? You could tell people it's a "water cooled turbo". :D

What do you get for speed with those motors? I'm seriously considering some Innovation's for my 311.

The "down pipes" will be smaller versions of the full-time underwater system on the PX MTI "Pair-A-Dice" if you saw that at the Miami show. I may get them powder-coated to match the paint on the transom to make them less obvious. Brownie (from Stainless Marine) runs the same setup on his little Donzi.

To try and keep it simple, I'd like to mount the shafts for the valves vertically, and connect each group together with a tie bar so one pneumatic actuator can close all four valves of each group. (Can't use electric solenoids outside the transom.)

My boat is "loaded to the gills" (12,000 wet) with genny, A/C, water heater, TV/VCR, 2 sets of ground tackle and enough of the wive's clothes to get by for two weeks, but we've seen 79.7 on GPS ("almost 80" in bar-speak). That's with DPX drives, since cruising efficiency is more important that all-out top speed for us. Love the engines: start flawlessly and never stall. (Did I mention they're loud, too?)

Can anyone post some pics of that cut out exhaust that you have been talking about? I would also like to do that but i dont understand that you all have done. Thanks

Two weeks of wife's clothes, LOL.....

Formula Outlaw - What rpm were you running with the 23 mirage props and what is your rpm with the 24 hydro's?

I am considering the same props on my new to me Formula 336 with 454 mag's which now has 23 mirage plus props.

Thanks-
Dave

Silent thunder exhaust tips
 

I am redoing a 1988 223ls mint, been in side climate controled storage for 11 years 245 hrs, I'm powering it with a 500 efi. I've read every ones ideas for thunder box mods and pretty much combined a few Ideas into this build. Ive removed the silent thunder box replaced the plywood and drilled 2.5, 3, and 5 inch holes in the bottom behind the stock drain holes, let the water in and out quicker, and let engine breath"Gooder" I am in desperate need of the stock rectangular tip, I am wanting the baffles to function as designed. If anyone has a set of these tips I need them bad, or if anyone has put round tips on and kept the baffles let me know how that worked out for you.