i have a 1996 38 top gun with 3a drives getting too much bow lift.im putting ssm5 on .. the 3a's are 4inches below the hull and 8 inches below the notch measureing the shaft to hull an notch .. what should the proper shaft hight be? to the hull or the notch?any imput appretiated

I had mine sky high on a 1993. Almost even with the bottom. The V's are 5.5" shorter so you are going to have to glass the transom or run boxes. Most likely glassing. Along with moving motor mounts down. Big Job. Straight bottom guns, run bow high to fly. Stepped hulls run flatter.

Agreed 100%. Our 3A shafts were pretty even with the hull. When running, I'd kick the drives out a bit and drop a little tab and you could feel the sweet spot the boat was happy to run in with minimum bow lift and unsticking the hull. I'd rather just mess with how you're running it (drive and tab setting) than go through the headache of running 5's. Just my .02

Here's an example of stills of us running in a video - photo of us pointing up was me running with the drives out a bit and no tabs down, trying to air it out for the helicopter. other shot is running in that sweet spot I was talking about. 3rd pic is where the drives were mounted for reference.

tyvm i see the answer is a lil bit more tab thks guy's

Try Spinning the props in

I also agree with Lucky Strike. Spin them in, pick up a little speed. Also, its expensive, but prop technology since the 1990's has gotten way better, a little tweek here and there. makes a huge difference in terms of the attitude of the boat. I was running 31 x 17 3/4 biggest diameter I could get. They were 4 blades. I had mine dialed in pretty good, however I know that their was even better options. I was able to run 97-98 but never the 100. If I kept the boat, and played with props it could have been done. I would not convert to 5s. I had 3As and almost 900HP. Just changed oil, ran great. Built to last.

like Tank said, pretty much even with the bottom. If you search me (cigrocket in the threads) some pictures of my transom and x dimension are around. They are sky high

Things to consider .
Raising the X dimension of your 3A's will require 2 things re-glassing the transom and moving the motor mount brackets that are mounted to your stringers . As you move the motor up it also moves the motors farther back in the bilge . Not difficult just time consuming if you do it yourself and a pain realigning everything ( expensive if you pay somebody else to do it ) .
If your 3A's are 4 inches below the deck and as Cigrocket said the 5's are 5.5 inches shorter you could mount the 5's not requiring any transom or engine modifications and with 3 inches of spacers added to the 5 drives you could get the X dimension as low as 1.5 inches below the deck . The 5's should also just bolt up to your current transom assembly .
Just my 2 cents
Rick G.

Caution on going too high - tough to get on plane. You can always space them down, or space the shaft lower than the hull surface.

I have 5s on my boat, when it was all redone, they were set at "even" with the bottom. Very hard to get it up on plane, and if you get caught in the rough and come off plane, or have to stop to check something, then get back up on plane, it can get ugly (could possibly sink your boat).

I am going to remove and replace the spacers with something in between, it killed my top end putting 5s 2" below surface w/ 18" diameter props. It does stay hooked up better in the bigger water. Sweet spot should be somewhere in between.

Play with props, learn how to run the boat, can always install longer tabs, will be cheaper in the end.

I agree, too high and getting on plane is the problem. Especially in swells, and big water. No Grip. So be careful. Yep, mine were something like 1-1.5 below the bottom. It was set up at TNT in Miami. Had the Transom Glassed and Raised the engines as well as the Drives.