drill 4 inch thru hull hole in wrong place

[chris0061]

so, I followed the directions from harden marine on drilling my holes for my thru hull I bought the deverters from them. anyway they had a measurement for alpha drives and one for bravo drives. well I used the alpha instructions since that's what's on my boat, only thing I got a 454 in front of it so they said I should have used the bravo layout. anyway my hole is off the difference in the two layouts and is there anyone out there that knows if and were I could get a offset hose to connect my tips. I'm off 1 3/4 inch with only 6 inches from end of diverter to transom .any help or advice will be apriciated.

 

[Scott Danforth]

find a welder to mod the exhaust, or do some fiberglass work

 

[tpenfield]

It is interesting that Hardin Marine based their instructions on the outdrive and not the engine. Maybe provide them with some customer feedback

​It seems to me that you could figure out the through-hull drilling by taking measurements from the exhaust elbows.

 

[AShipShow]

Are you too low or too high? If the hole is too low, then you could probably cut the downward part of the elbow and add a section of hose to extend it... If your too short, then your going to need to get it modified...

On a side note.. how do you have an alpha drive on a 454? Is that a factory setup? I thought all 454s cames with Bravo drives...

 

[alldodge]

When I repower the last time I had to move my holes because of 3 inch higher riser install. Not that hard to fix. I ran thru the same issue until figuring out another way to fix it. Your going to need some epoxy resin, or could probably use 3M 5200, but I used epoxy. Start looking on page 8

http://forums.iboats.com/forum/engi...rmula-27pc-complete-power-plant-rebuild/page8

 

[thumpar]

Are you too low or too high? If the hole is too low, then you could probably cut the downward part of the elbow and add a section of hose to extend it... If your too short, then your going to need to get it modified...

On a side note.. how do you have an alpha drive on a 454? Is that a factory setup? I thought all 454s cames with Bravo drives...

They did for a few years and had a lower ratio Alpha mated to it. They came out with the Bravo soon after and stopped doing it.

 

[tpenfield]

the Bravo outdrives came out in 1988, but the 454 (7.4L) engines were available a few years earlier. so there are a few 454/alpha combos. Additionally, you once in a while find a boat that had the whole outdrive replaced, but they cheaped out and did the Alpha instead of the Bravo.

Anyway, The engine dictates the exhaust dimensions for thru-hull exhaust.