37' Drive Spacer question
 

I purchased a 37' last year it had 2" spacers on it already. I've since re powered and went from standard B1 drives to XR's. my question is to you guys, are drive spacers needed or anyone using them? How do I determine if they're needed to not? I'm guessing measuring x dimensions. I figure there's enough of you guys on here that know these boats well enough without any measuring being needed! Thanks in advance.

I don't recall hearing of anyone running spacers on the stepped 37's

I'm with you, I've never seen any with them other than mine, so that's why I asked lol. It had 500 EFI's to start out with and ran in the low 80's gps, which is pretty good I thought. Trying to get up into the triple digits now with bigger power. I went ahead and put the spacers on my XR's just because it already had them. Seems to me it would slow me down since everyone goes to shorties for speed?? Idk, may need to remove them and run. Just sounds like a lot of work lol.

Leave the spacers as a baseline to see where your new power puts you compares to your old HP500's. Then pull the spacers and run again.

It is a lot of work but your trying to go from 80's to 100's. It not gonna happen without testing.

Before buying my 37' AT I had a 32' Sunsation. It was unknown until after I purchased it whether it had standard lowers on the ITS boxes or 2" shorties. I purchased the boat with the standard lowers and no matter what prop we tried it ran 80 MPH. I knew it should have been faster than that so I did more research and found that it was originally rigged with 2 inch shorties. The boat picked up 8 - 9 MPH with the change. Having too much gear case in the water was the reason for it hitting a wall at 80. As others have mentioned I would run it with the new power and spacers and see how it runs. If you feel it should be faster you may want to take the spacer out altogether or try a 1 inch spacer.

Thanks for all the input guys. I knew y'all would chime in and help steer me and confirm any thoughts. I'll def post when I get back in the water and start my testing!!

IIRC, you have one of the earlier stepped hulls. Remember, the step height has changed a few times over the years as "stock power" got more robust. As such, you may not be able to compare notes with other hulls of different years. The step has varied from 5" to 3-4" over the years.

Harry Schoell designed the boat so that standard mount (direct to transom) standard length B1 drives would have the:
-Prop shafts
-Aft edge of the transom
-Aft edge of the step
...all on the same plane. That's what makes this hull perform well, especially at neutral or near-neutral trim. The step gives the boat natural angle-of-attack (which is why steps where originally designed).

Try it with the spacers that worked before. Someone put them in there for a reason.
BUT, as speeds increase, the inefficient hydrodynamics of the bullet of the Bravo1 drive is going to force the transom upward. That's not good for handling if the edge of the transom is barely wet. Perhaps nose-cones will be in your future as well.

I added 2" spacers in my old set up with the XR's.
Worked very well and settled it down nicely. 100+
I have them in the barn if you are looking for a set. I used the IMCO lowers with them.