in advance, thanks for any and all input here especially any pro and/or past experience in either of these matters.

i will try to articulate the plan and obstruction(s) that have to be delt with so you can get a better picture of whats going on
and the reasons for the questions, and how i'm trying to get it all sorted out,

question 1
does it matter which way the aluminum angle points ?
the angle that bolts to the stringers and the offshore engine plate mounts

question 2
what would you do about the patch in the transom ?
the bottom of the bravo transom assembly is in virgin transom, the top is in the patch,
(forward gear pushes on bottom and pulls on top of transom assy)

the plywood patch is a plug (not overlapped onto original transom) and is glassed w/ about 1/4 inch worth of bi ax
on the outside and about 1/8 inch of biax on the inside.
(heck for all i know it's tri ax, but it'd have to be ground down slowly looking for the 90 layer)

tell ya the truth the material looks bigger than 1708 bi ax (heavier weight) the glass work on the patch just looks beefy
and very well executed.
but w/o the ply overlap it's all down to the glass shearing or peeling and the boat goes to bottom.
the glass on the patch extends 3 inches around the sides and bottom, maybe 6 on the top (see photo)

the guy i bought the boat from is a pro glass guy, he built this boat and has or had a center console mold as of a few
years ago, not sure if he's still building or not, so when he says the patch will hold and it's good to go i believe him,
but you see my dilema, and this is in no way a calling out, it's tech advice only.

the engine is getting moved 12 inches forward of stock location (imco extension box shaft only)
the engine gets a rear mercury offshore plate. the fylwheel cover is just that, and doesn't need to hit the locating dowels
in order to be clocked like if it had a transmission or bravo driveline (jackshaft)

since the engine and transom assembly are not going to be tied together any extra strength the transom would have
from being bolted to the engine is non existent, and so, the reason for the patch question.

IF NECESSARY, the plan for the patch is in photo, route out line to 7/8 depth (approx 3 inches outside old patch),
1708 to dotted line as necessary to build back up. (approx 3 inches past new patch)

since the hole is cut i would use the transom assy mounting holes to hold the patch in place and later use the holes and cutout
from the outside to re drill and recut out the new patch.

onto the next bit

the angle is 5 x 5 x 1/2 6061 w/ 5 x 12 x 1/2 6061 backing plates, all bolts will be grade 8

number 1 obstacle, this is a 1 man show out of a 10x12 shed with basic hand tools so everything has to be planned
to the last detail before execution and everything needs set up and broke down each day.

no gantry, the boat has to go down the street where a towmotor will put an almost bare block in so alignment can
be figured out. that means boat has to go back in the drive and get leveled on the jack stands and water level,
since the engine won't be on the transom.

the block is a mark 4 with crank bearings, crank and flywheel, the plan is to put the 496 bellhousing, engine coupler and
496 front mount onto the mark 4, so long as the distance from the bell face to the front mount pad and from the bell face
to the flywheel face where the coupler goes is the same. extra metric and american bolts are on order.

set and align engine on the transom to mark depth on custom made alignment tool, then take off the bell housing and
put on the rear mercury offshore plate. from there mark tool the 12 inches, slide engine forward and
align to balls on nasa specs.

no gantry is the problem here, so if the stringers needed grinding so angle lays flat and sqaure to mounts, couldn't do it with
an engine in the way so the plan is clamp the angle to some angle and clamp them to stringers at and around the area
that the angle will be bolted to the stringers check for flat and sqaure, grind if necessary.

i'd like to put the angle facing forward up front and backward on rear (as pictured),
but if they fit better facing either way does it matter.
does it matter if the mount is in front, behind, or between the angle like i'd like to do

reason for 5 inch angle was bigger clamping area on stringers, angles will have to cut to lengths long as possible (looks like 8 inches)
and be trimmed to fit on the plate mounts, also angles will be at or close to stringer top.

any other pics or dimensions, just ask
thanks

what boat is this? if it is a straight bottom vee then why are you moving the engine forward? as for the patch, given the looks of how it was done I would not trust it but maybe glass dave can chime in. the wood is just a plug and the glass looks like a pretty minimal overlap so it would hold for a while but long term is questionable. for the aluminum plates, I always put them behind the engine plate angled back. that way you can lower the engine in and push it back against the angle and run the bolts in. if you set it so you have to slide the engine plates in between the angles you will tend to really fight getting it down into place.

awesome, thank you.
your not the first person to suggest installing the angles that way and for the exact same reason.

the boat is a 26 x 8 single V, there is a thread in the resto section HART THROB.
it's a no cabin light layup and my theory behind moving the engine forward is more about balance than a gain in speed.

Some race boats current and past have done the mounts both ways. (Front engine mount in front of the angle, rear engine mount behind the angle) in very rough conditions it will bend and bow the mounts as crazy as that seems. If you aren’t too set on that style mount I really like durability of a piece of angle mounted horizontally along the stringer with offshore mounts that sit on the angle. That way you set the motor down and slide it into place. Similar to how the supercat engines are mounted.

As far as moving the engine forward I like that idea also. There are Afew competitive current sub 30’ race boats that have this same thing done with good results.

more good advice, thank you

i asked about a mount like that, "the rail system" and some members put up some links for them.
would be a great option especially if it could be made for 12 inches ( imco shaft ) and 7 inches ( its shaft ),
or multiple locations for the jack shaft.
with exhaust tails made to drop then turn and exit straight out the transom
the engine could be moved back and forth to find best results.

but in the end the stringers are 34 inches in between and are 2 inches thick.
plus the mercury front plate doesn't fit on the 496, it has to use the gil cradle mount that came with it
and not knowing enough about them and trying to explain and have custom made stuff
i figured standard offshore plates and aluminum angle was the way to go.

99 percent the angles will get mounted behind both plates and facing rear.

moving the engine forward is a leap of faith, so it's good to hear others have done it with good results.

short of having someone fabricate you mounts I don’t think there is going to be anything you can purchase that will work on a rail for your engine. However a good welder/fabricator could take your cradle and make feet to sit on the rail.

If your boat was originally set up with a 5 it was atleast forward 10” possibly 12 if it was a plug in transmission. So you’re really just sliding it forward to it’s location when it had a 5 on it. My engine with a 5 on a box is 16” from the transom and there are others that are 2 and 3’ from the transom one being a bravo boat and one being a ssm boat. I think you’ll be just fine with the engine forward and will have no issues carrying the bow. I wish mine was another 12-14” forward to be completely honest.

yep, #5 on a box was original set up,
new set up, the engine will probably be close to original.
merc says, bravo @ crank center, the engine bell housing face is 8 1/2 inches from transom (stock)
plus 12 (imco shaft) puts it at 20 1/2 and front pulley at 47.
the engine room @ crank center from transom to gas tank bulkhead is 64 inches

i think you’re going to be just fine. All you need now is a period correct 12.5:1 468 and you should be in business lol. Good luck with the project. I saw your pm from awhile back and sent you my number. I didn’t hear back but if you have any questions about anything that I can help with don’t hesitate to hit me up. I Have alittle experience setting up similar boats.

appreciate that,
yeah, the question was about the seat base set up you have but with everything going on and the bolster i have now
can be changed out down the road to just about anything i'd want.
i didn't want to waste any of your time for something that isn't going to happen right now.

focus is on finishing up so the engine can get installed, with a side order of gas tank template
to get that ordered up.

as far as mounting if you wanted to do a rail system, you could use a front mount for a V-drive, install 2 long angles down the stringers and the small angle mounts would sit right on them. My V-drive eliminator daytona I redid this way a couple of years ago..pretty slick setup..