Way2Slow is OMC, don't think he is all that familiar with 135 Merc?

135 Merc comes in several engine blocks from inline 6 to V6, what engine are you asking about? For example the V6 is a detuned 150-175 hp engine. The inline 6 in the 135 hp is top end stock hp carb engine, light weight smaller CC block that can be modified to turn 8,000 rpm's, dought anyone is using a inline 6 race engine and doesn't know It. The V6 is easy to add 75 hp.

Tom

Yep, back then, there were no V6 Merc's.  As mentioned, the 135BHP was an I6, with a small brass, bullet type lower unit and a huge exhaust port at the anticav plate.  Stickly intended for racing.

As WRB mentioned, I haven't done much with merc's since the early 70's.  

I thought the only 135 V6 they made was the Mariner.

I like the OMC looper motors, got into those a few years after they came out with it in the 60's with the 3 cylinder models.  Those could be made to scream.  Then the V6's in the mid 80's.  When OMC developed those, they left so much horse power on the table, it very easy to get bunches of cheap horse power out of them.  The things were just built like a tank.  

Mercury did a much better job in manufacturing, so they got a much better HP to Weight ratio, but didn't have all the free extra power that could easily be gotten.  To modify a merc, you have to rob Peter to pay Paul.  In other words, if you want bunches of horse power, you have to give up bunches of bottom end torque (hole shot), and spin them a zillion RPM so they have to go on lighter boats to take advantage of that extra HP.  

I can take a 200hp 3.0 OMC motor, get over 300hp (well over 400hp from a 3.3) from it and still launch a heavy Stratos 201 or Ranger like they were shot out of a canon, and not have to turn it that zillion rpm to get that 300hp.

All I know is the cowl says mercury 135 and it flies haha. I didn’t even know they had a 135 until the first time I saw that motor 

It's very common for people to change decals on motors when they are similar looking , especially in areas where the law or local guidelines don't allow a motor the have more horse power than the hull is rated.