how much horsepower for pre alpha

[boatnut74]

I am currently restoring a starcraft chieftain and am looking to upgrade from the inline six possibly to a v8. I have all sorts of small block chevy parts sitting around. I would keep the power to about 300hp. Would my pre alpha mc1 drive be able to handle this? I wont be racing or playing real hard with it but am on a budget and could build this engine fairly cheap. Another thing that has crossed my mind is finding an alpha 1 gen 1 drive as i believe this will bolt to my existing gimbal ring.

 

[HT32BSX115]

Re: how much horsepower for pre alpha

Howdy,


Back in the Merc #1 days, Mercury used the #1 with the 4 and 6cyl engines (except the 292 cu-in 6)

The 292 & V-8's (in 66 the 409 cu-in V-8 was rated at 310hp) were put in front of a Mercruiser #2.

I think you might be pushing it if you were to put a V-8 that actually did make 300hp. (you gonna dyno it before you install it?)

A Alpha or GEN II might be a better choice. I also think you'd be hard pressed to make 300 real hp with most typical 5.7 builds unless you go with high compression, a trick cam and plan on turning it well over 5000 RPM. (characteristics that don't work well in I/O's with wet exhaust)

Having said that, I know a couple of people that successfully put a SBC in front of a #1 and it survived. (I don't know how long though)

A friend of my dad put a 327 in front of one back in the late 60's and ran it for more than a couple of years.....

 

[boatnut74]

Re: how much horsepower for pre alpha

Im not real familiar with all the mercruiser drives out there. I was actually thinking of a 327ci motor as I have several parts for that. It would probably be closer to 250hp as i want to keep the compression down and dont plan on using a radical cam.

 

[HT32BSX115]

Re: how much horsepower for pre alpha

and dont plan on using a radical cam.

A marine cam or truck/RV type cam helps to reduce/prevent reversion. They also allow the engine to make it's most torque and HP below 5000 RPM where most (non-racing) stern drives want to run anyway.....

 

[cr2k]

Re: how much horsepower for pre alpha

You will need the upper from a V-8 to get the right gear ratio.

 

[boatnut74]

Re: how much horsepower for pre alpha

Right now im just keeping my options open. It would be nice to have the v8 power but will depend greatly on cost of parts to convert it over.

 

[Eric 3.7LX Alpha 1]

Re: how much horsepower for pre alpha

You can buy the tools and parts to switch your upper to the new ratio, but the cost to do it would put close to a new aftermarket upper.
http://www.sterndrive.cc/mm5/merchant.mvc?Screen=CTGY&Category_Code=MercruiserAlphaUpperSterndrive

 

[dubs283]

Re: how much horsepower for pre alpha

It would be nice to have the v8 power but will depend greatly on cost of parts to convert it over.

look for a donor drive from a V-8 - craigslist, e-bay, etc...

this will help keep costs down but be sure you know what to look for in the drive, sometimes stuff is cheap for a reason!!

FWIW - an alpha drive/transom assy would bolt up perfect - if you can find the rotten boat with good parts that is

 

[wca_tim]

Re: how much horsepower for pre alpha

Your gear ratio will be fine with a mild v8, you'll just need to prop accordingly...