Have u tried running with the engine hatch off or cracked a little? A buddy of mine had trouble with his twin scarab the port motor was slightly higher than the starboard. Under heavy load the port motor would stumble and carry on. Never got the rpm the starboard got. Come to find out the ribs in the hatch were choking out the motor...

Here you go.

http://www.youfixcars.com/engine-vacuum-tests.html

What do you guys think of the results? Seems to pull decent vacuum for fairly heavily cammed solid rollers...my 621 drag car is lucky to get 6-7" at idle and fluctuates more with the lope. And with both motors nearly identical I am back to a loss again....

Well on the good side at least these motors are getting a complete tune up with baseline measurements if anything else was to deteriorate in the future....by the way the vac ports worked out pretty slick.

I'm thinking of taking the vac gauge and timing light with me to river to load the motors and see if anything changes with said load.

Maybe a wiped lobe on the cam?
Unusual but not impossible on a billet roller.

LIke you say the vaccum tests look to be ok. According to that article, more fluctation would indicate a problem. Seems like all cylinders are working equal with no load. Hopefully the load test will tell you something. It wouldn't hurt to open the hatch a bit, give it som fresh air. Usually that is a WOT item, but you never know. A couple of wooden blocks to suport the hatch so it isn't hanging loose helps it from auto ejecting.. :)

The one thing I think you have not swapped are the distributors???

A wiped cam lobe would have show up when you lashed the valves I believe. It always has for me. :(

Keep at it, it will surface!

Yeah, I didn't see anything telling when I ran the valves. And you would think a flattened cam lobe would have showed up on vac test? I will run timing and vac while on the water and see what happens there. You are right, only thing left I haven't swapped would be distributors. Both of them show good at this point. I guess the load test will indicate if I should give that a try or not. I'll report back

Good luck with it!

Well not completely sure what did what but....had slight miss low load coming out of no wake. Then miss seemed to go away. Weak motor now ran within 200 rpm of the other motor. Carbs swapped, went with new wix separators in place of the fram, and ran the 5 blades. Also shielded pickup wires to box from dist with foil and re-routed them. I tell you the 5 blade p5-x 31 pitch run the boat much much better than the 34 bravo 4. Planning, handling, turning ect...ran up against the 6k limiters in a hurry but well worth it other than that. For now will leave everything swapped and see how it does next time out. May be a slight delay as our dauhter is due any day now! So until then I wanted to thank everybody for the help to get to this point. Sincerely thank you. -Chris

Picking up noise on the dist wires is a possibility. I was seeing a 90* jump in timing on the dampner at a idle, and I think it was caused by spark scatter from the plug wires.
Glad you are at a point of some solution. Hopefully all will go well from here on in.

Dick