Inboard replacing

QBhoy

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or just order the parts, build the motor in the garage or living room (depending on marital status) and when complete, swap motors
Haha. If I had it my way…my merc 150 2.0 would be in the dining room just now. Alas…I’d soon be single. Once had a 800cc Yamaha ski engine top end on the kitchen work tops…I learned my lesson that day.
Scott…I know you and many others that have suggested just building a stroker and going carb…is probably the most sensible way to go. But for some reason…I just have an urge to stick to a stock mpi 6.2. Smart craft and all that are appealing to me for some reason. Good mix of modern, efficient and fast, is what I’m after. Just think it would be amazing to see this hull pushed a little more than it is. It’s not even breaking sweat as she is now. Rock solid stable once it’s up on the pad. Could take your hands off the wheel and reach for a beer, if you wanted to, doing mid 60’s. It’s that well behaved. Heavy and planted thing.
She will be just over 3400 lbs with some fuel and me in her alone. Very heavy for an 18ft boat. But very clever apex stepped and padded hull too.
If I go too much power..I’d think the wee alpha might be the worry.
 

Scott06

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If I go too much power.. ’d think the wee alpha might be the worry.
Would bet if you get a 5.7 or 6.2 long block have one of the ECU programmers reprogram your ECU it would work well. All Dodge had recommended a place that does it was like $400 or maybe a tad more.

Willing to bet unless you are jumping out of the water in a lighter boat like yours an alpha will last fairly well. You can also buy several alpha drives for the cost of a bravo conversion..
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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no reason to go carb if you want to stick with MPI as stated, just re-map your existing ECM

you could also switch to closed cooling at the same time.

no reason to go away from the alpha. you do need to run a rev limiter. not when in the water, to shut it down when wave jumping.
 

QBhoy

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no reason to go carb if you want to stick with MPI as stated, just re-map your existing ECM

you could also switch to closed cooling at the same time.

no reason to go away from the alpha. you do need to run a rev limiter. not when in the water, to shut it down when wave jumping.
Cheers Scott. It’s an exclusively fresh water boat to be fair. Rpm limiter now is around 5150 or there abouts. Alpha has done me well so far. Like new still. Never open the throttle from a standstill either. Should be ok.
 

QBhoy

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Would bet if you get a 5.7 or 6.2 long block have one of the ECU programmers reprogram your ECU it would work well. All Dodge had recommended a place that does it was like $400 or maybe a tad more.

Willing to bet unless you are jumping out of the water in a lighter boat like yours an alpha will last fairly well. You can also buy several alpha drives for the cost of a bravo conversion..
Totally agree Scott. I’ve always said the same about the alpha bravo cost thing. I’d think an alpha might be less of a drag through the water too perhaps.
About the acquiring of parts etc. You guys are so lucky over there for getting a market for these things. It’s just not really a thing here. One or two guys that may be about for it…but the cost of getting anything from America across here now is just crazy. Tax and all that recently imposed. Huge shortage of new American generic boats here too. The market for your average US bayliner or maxum etc used has gone through the roof here.
 

Scott06

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Something like the Davis Unified Ignition box that's $150? Thinking I may want to add a rev limiter to my setup this year.
Whats your current ignition ? If it is a thunderbolt V it already has one.
 

QBhoy

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Whats your current ignition ? If it is a thunderbolt V it already has one.
It’s an mpi scott. Delco system I’d think. Has the horrendous flat cap diz.
Ecu will be the 555 or whatever it’s called
 

achris

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.... I’d think an alpha might be less of a drag through the water too perhaps....
Nope. A Bravo 1 has a very similar underwater profile to an Alpha...

Alpha is good to about 65mph, a Bravo 1 is good to about 100mph (slightly longer gearcase pushes the blowout speed up)...

Chris....
 

QBhoy

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Nope. A Bravo 1 has a very similar underwater profile to an Alpha...

Alpha is good to about 65mph, a Bravo 1 is good to about 100mph (slightly longer gearcase pushes the blowout speed up)...

Chris....
I get that chris. Fair play. Just that the alpha is a little more slender in its profile perhaps. It does me well anyway. No sign of it letting go at 65…and a couple of 67’s and a 68 or two. 70 would do me just fine, with a lovely 6.2 😁
 

QBhoy

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It’s an mpi scott. Delco system I’d think. Has the horrendous flat cap diz.
Ecu will be the 555 or whatever it’s called
Sorry. I replied to some thing I shouldn’t have there. Sorry to hi jack the post too. Enough about me.
 

achris

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I get that chris. Fair play. Just that the alpha is a little more slender in its profile perhaps. It does me well anyway. No sign of it letting go at 65…and a couple of 67’s and a 68 or two. 70 would do me just fine, with a lovely 6.2 😁
Alpha and Bravo 1 run the same props. Their diameters/profiles are the same. You may be looking at the Bravo 2.
 

QBhoy

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It’s an mpi scott. Delco system I’d think. Has the horrendous flat cap diz.
Ecu will be the 555 or whatever it’s called
Sorry. I replied to some thing I shouldn’t have there. Sorry to hi jack the post too. Enough i
Alpha and Bravo 1 run the same props. Their diameters/profiles are the same. You may be looking at the Bravo 2.
Was referring to the profile of the lower gear case chris, more than anything.
 
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