I personally have not. What we are saying is...most people who have built motors (street cars, drag, circle track, boats, etc.), and have done the research...dont use gear drive set-ups. It's a known and proven fact about the vibrations/harmonics transfered throughout your entire cam/valvetrain with a gear drive. Look at it this way...with a gear drive...the crank is actually DIRECTLY driving the cam...which is driving the rest of the valvetrain. Any vibrations...harmonics...tremors...or bumps and thumps, are being sent to the top end of your motor. The roller chain acts like a buffer...or absorber in the system. It's basically healthier for the rest of the system. Especially in a boat motor.

technicaly there should be no harmonics...but it sounds plausable...the reality is there are non...my valve train and engine run perfect with a gear drive...but its not a 150 buck one..those i would say yes....but with a floating idler gear and a good one u wont have problems..

I use a millodon BBC one..on a 600 CI 800+ HP N/A 10:1 engine..with absolute no problems !!!!!

I was just curious because we've been running the Milodon gear drives in our boats since the late 90s and I can't say they've ever caused a problem. We ran the Cloyes hex adjust prior to the gear drive and other billet stuff before that. The only thing I can say for sure about the gear drive, it takes a long time to wear out and the timing doesn't jump around at all. The gear drive is probably over kill if you're not running a solid roller.

My reverse rotation motor also use gear drive but there is no benefit over the chain on the other motor. A good double roller is the way to go and a lot cheaper and quieter and better over all.

Thanks for all the replys it's timing chains me on the new motors.

Jesel belt drive. A little more expensive but sure does look nice.

Rollmaster are very good