HPBCANADA.COM

The topic comes up every spring and opinions have changed as more T guys modify their OMC 56 cubic inch motors.
Here is a post about the top SST 60 motors racing in APR Superleague in 2008.
“The SST-60 race block is the loss foam block not the permanent mold style. It also has bridge port sleeves in it which most of the stock blocks do not have. The stock version will run and have great acceleration but no where near enough top end. I had a stock block built at one time by mistake and when I figured out that occured and switched to the racing block picked up 800 rpm the first time I put it on the boat. The casting # on the race block is 334474 and has webbing across the back of the block towards the exhuast side (that is the easiest way to tell it is a loss foam) Advanced Sleeve sells new SST60 sleeves that you can put into the stock block and make it a racing block as long as it is loss foam you will be legal.
NOW THIS STATEMENT!
I typically turned 8400-8800 depending on the prop I used. On several occasions I did get 9000 out of it.”

Prior to this time the Top SST 60 motors turned 7700 to 7800 rpm. The APBA engine spec is the same. Most speed records for the class were set prior to these higher rpm motors.

Remember the SST 60 powerhead was designed for a tunnel. The motors horsepower reduces greatly over 7300 and a T boat has far more drag than a tunnel. The tunnel needs less horsepower to go faster. The higher rpm works on the tunnel.

Since 2014 the recommendation for the SST 60 is not to exceed 7700 rpm even on a tunnel. Major reason was poor engine life span.

I have made these same suggestions before.
- follow the SST 60 engine spec sheet
- keep the rpm below 7700
- try a tuner 1 to 1.5 inches longer than he SST 60 tuner..
- if you go wider on the porting start with 76D main jets
- don’t go higher on the exhaust port than the SST 60 Spec
- crankshafts are not all the same ...some are better
- the production 1986-7 block is best...but marginal if the foam cast block is race prep.

The difference between a good powerhead and a super powerhead is 2 mph. The difference between a good prop and a great prop is 3 mph.

A lake runner only needs top end speed. A raceboat needs acceleration as well. Race motors, prop selection and boat setup are different .