Sleeper

[xtraham]

I have a 1976 70hp Johnson on my little boat now
got a larger engine to put on for this comming year
my question, is there anything I can play with on the 70
while i am running the other engine to make the 70 pump out some power
I just want to play with it and see how much power I can get out of it
perfomance parts, machining, exhaust, carbs etc. ?

 

[WillyBWright]

Re: Sleeper

The most you could get out it is another 5 Hp and the 70s 75 triples had a tendency to melt down. A set of 75 carbs might help, boyesen reeds. You might get lucky and find a 75 Stinger gearcase. I'm not sure which years, but some of the Stinger gearcases were smaller (twins-size) which would reduce drag and give you a few more mph.

I'll bet Dhadley knows a lot of tricks. Those motors dominated the class in raceboats in their day.

 

[Dhadley]

Re: Sleeper

Yep. You can get close to 100 (crankshaft) hp but it all depends on how far you want to go (cubic $$$). The big question is hull design. No sense putting a Mod 50 on a non-pad bottom or non-tunnel boat.

 

[xtraham]

Re: Sleeper

thought if parts are available and can get the info on how too's to make that thing hum,I would look for a nice little fast haul or a scow just to play with......

 

[Dhadley]

Re: Sleeper

The Mod 50's started as a 49 cid motor, like yours, but had radical porting and 3, 2 barrel carbs. You can go anywhere from your stock unit to the Mod 50, it just depends on what you want to spend.

If we were doing it, we'd start with maxing out what you have as far as set up and prop. Then add the reeds, then compression, then open the exhaust and dry stack it.

Depending on what boat you get and the speed, at some point you'll get into gearcase shape and altering the water pick up location.

And naturally, props. Probably several.

 

[xtraham]

Re: Sleeper

thanks,
I going to start looking for a haul,
will let ya know what I come up with, I rember the 3 cyl engine's with dry exhaust and thats the way I want to go,
when I start I want to go all the way