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FE and EP boats never ran set back on the boat. When the APBA EP speed record as set at 70 MPH. Joe's Allison had 1 foot of set back.
In T Class we see set back on most boats. T750 boats like Thom's Allison run over 6 inches of set back.

This VooDoo has both a CMC trim plus a jack plate. YEP!!!
https://www.kijiji.ca/v-powerboat-motor ... nFlag=true

Our T850 Yamaha Critchfield has NO set back
The Toaster runs 2 inches of set back.

Most of the jack plates I see in T Classes are made for large motors. The CMC trim unit on the VooDoo above weighs 45 lbs, the jack plate has to weigh 35 lbs. THAT'S 80 EXTRA POUNDS ADDED TO THE BOAT!!

Set back does work on a T750 boat. I'm not a believer in set back on a T850 race boat. YET!

In is the race off season. Good time to discuss this topic. Certainly will benefit people with T Boats.

WHAT SIZE OF SET BACK HAVE YOU TRIED AND HOW DID IT WORK OUT??

It is all relative the the hull and where the forward to back centre of gravity is. I'm pretty sure hulls have an optimum front to back center of gravity and having options for setback of the motor is a tuning option for balance. Anyhow, that's just a generalization and there are more interactions at play when it comes to setback, but that's what I've seen so far for as it relates to top speed in a straight line.

Based on Joe's APBA record....more is better.
On the race oval more is not better. More causes the boat to be slower in the turns. More causes the boat to fly entering the turns and not set.
You can find the balance point of the boat without using a set back. Many like the jack plate because it is an easy way to adjust engine height.
Racers want to reduce weight, yet some run heavy yamaha/rude trim with a V6 jack plate which adds a lot of weight.
Other racers run SST60 thru transom trim. Some with no set back and others with set back. A much lighter set up.

It's nice to have power trim. But RACING with a clock start would it not be better in T750 to run a very light big set back [over 6 inches] and a very light clamp bracket assembly with no trim. The more set back you have the less trim you use, so do you need trim? You can drive a T750 boat wide open most of the time and only lift for a moment to set the boat for the turn.

On the 750 boat we run 4" setback @11lbs and power trim set up is 9lbs. We tried an extra two inches of set back at the beginning and hooked a couple of times, could have been water conditions etc. but we took the two inches out and it seems to run ok

I dont know the how much weight was added doing our power trim over the sst 60 bracket but its not much maybe 10-15 pounds tops. We are using the hevi kev setback bracket for tuck and the boat works very well. I dont think the delta needs any more setback then that with the sst60. I would think moving the weight back further and higher would have negative effects on handling aspects

When we had the surf 60 on the delta, we ran a 4" setback jackplate at about 10 pounds with no trim. The boat ran half decent. We got it doing just under 50mph with no setup or prop testing but never went any further with that motor.

5 lb setback... 3/8" plate, 2" nylon stock cut to any length, long transom bolts.

5 lb setback... 3/8" plate, 2" nylon stock cut to any length, long transom bolts.

Now that is different!

T-Cat guys do thing different.
Worth noting that the 3'8" plate is resting on 1/8" tab welded to bottom of stainless steel open transom.
It is clean and elegant though.
I use transom wedges to accomplish the same thing but like this better.

You could also use threaded stainless steel rods and composite spacing blocks. That way you could start at 2 inches of set back and then extend the rods and adding blocks until you found the best set back for your application.

I know many non racers run the aftermarket trim assembles like the CMC 35 & 130 models, Bob's Machine Shop has a large selection of models and lots of brackets and spacers. There are a few other less common suppliers. Anyone used them?

For new people installing set backs......Because MOST transoms are on an angle tilting back....the more set back you use the lower the motor is in the water.....you need to raise the motor....the further you go back the higher you need to raise the motor. The set back changes the boat's handling.
In most cases it makes the nose lighter. Normally the boat requires less trim and has improved top end. On a racing T boat it is a fine line because the boats run past their safe limit. It does not take much of a driving error for the boat to HOOK, BARREL ROLL or BLOW OVER. You make one small adjustment at a time and you TEST. Lake testing is NOT equal to race conditions.