Havasu Cig

You can buy after market gear sets in a 1.36 ratio. At the time I bought mine the 1.35 was not available from Merc yet, so I purchased the after market set from Teague.

MitchStellin

Thanks guys, PO you are right the only difference is the ratio, all other internals are the same, I am glad to hear the 1:36 can handle more power and may be better out of the hole, more top end is also a nice benefit It sounds like there is no real big deal between the two, from what I am seeing here 1:36 may be a better set up in the long run for reliability and future power increases. I wonder if there is a big difference in RPMs, and I would have thought you would lose top end with the smaller gear, I am glad to see I may be wrong.

dlbCheckmate

Thanks Guys. I have a 251 Convinsor with a 572 cu. Its a new motor so I will see how things go. I also have a 12" Imco neutral box with a 2" shortie. I have both uppers 1.36 and 1.5 so I guess I'll have to try both. Getting ready to Dyno the motor Thursday, can't wait to start testing !!!

aero-offshore

Hey dlbcheckmate, How did you come out?

jpclear

I think Matt really nailed the answer. When you need a prop that gets in the mid 30's pitch to keep your engine RPM's where you want it at top speed, then it's time to consider the gear ratio change and lower prop pitch. Think about it guys; those blades will become sideways paddle wheels if you add too much pitch and then your prop efficiency will drop. Generally speaking, we don't need to worry about this unless we have something with a 1/1.5 ratio that is running in the 90's. --- JP

throttleup

I work with many clients who were ill advised to go with a 1.36 ratio because they ran out of prop pitch due to a poor set up on the boat.

Some boats run faster with a 1.36 than a 1.5 ratio. I wouldn't even consider the 1.36 ratio unless you have a top end speed in the 90's.

Some boats with the 496 HO have a higher top speed with the 1.65 ratio than the 1.5. These are typically boats that have a top speed of 70-80.

The best thing to do is to try all the different gear ratios with the proper prop pitch to find out what is the best set up. Of course that isn't practical for most of us. So make the best of what you have. If you have to go below a prop in the 22-24 range then you are limited with the selection of high performance props so it would be necessary to go with a lower (higher numerically) gear ratio. Keep the prop pitch in the high 20's to low 30's, that is the best and most efficient pitch range.

Matt

monsta

Another factor to consider is prop speed. Smaller pitch turning faster is more efficient than a steeper pitch turning slower. RPM, X-dimension, stepped or unstepped, notch, pad are all differential's to consider. In my experience prop speed is the true factor of transmitting power to the water for high performance application's. Note all gladiator's come with 1:36. Bottom line spend some quality time during your dial in.