20" mid will measure 20" from inside bottom of transom bracket to the Cavitation plate. From Cavitation plate to prop shaft center on a V8 is about another 9.5", about 8.5" on a V6. Something like that if I remember correctly. Anyway between that transom angle and bracket angle, all planes may not be perfectly true, the horizontal planes of the running surface and bracket may be slightly off. On 31" of setback that can amount to a little. Remember its home made, not a Stainless Marine work of art, but its pretty close.

It worked right? thats what counts. I'll start at 1" below bottom and go up from there.
It has been too cold down here to paint, so thats as far as i am getting this year. i'll get the transom, mid, and gear case painted while i am at work, then start assembling the week of jan 10.
still have to paint the bilge, and find a helm for my new steering. also ordered a set of CCM reeds that i need to install.

I dont think your going to be seeing speeds where you will need your propshaft any higher than 1" below....you could probably run it even lower than that and get good results.....

my last 24 superboat was 3-1/2" below (original owner was a water ski guy) and with the right prop went a tick under 70 on GPS all the time....that was a 24 superboat with a stock 250 EFI Merc.......

super high engine heights and nose cones or sportmaster gearcases only work on boats that are going 75-80 plus......

in your case i think getting the motor running 100% and prop selection are going to be key....

well at least your not spending any money.LOL

dd you have it on a bracket or on the transom? i'll have 30" of setback so i can run it pretty high. previously it was setback 32" and was 6" below bottom, and i was doing 61

it hasnt been too hard of a hit, but it aint over yet

some progress:
freshly painted transom

Fresh holes:

New bracket:

Cool! Great work!

Haven't been on here for a while. Boat and bracket look great.

slow and steady wins the race. Still need to purge the steering, and finish rigging the engine. then should be a go. waiting on a few parts in the mail.

Not much drag on that lower!