Horsepower And Torque

[FORMULA83BEAST]

Hi everyone!

I am looking at buying an o/d from SEI. My concern is that I am currently in process of building a 350 chev/merc.Planning on producing 350 ponies roughly the same with torque.Will the o/d for the 260 horse 350 alpha 1's hold up with my motor, and if so does it void any warranty? If not what would you reccomend for the max on horsepower & torque?

[Tech Support]

The Alpha drives are rated for up to 300HP. Not really sure of max torque but probably less than 300 ft/lb. Some people have success using the Alpha drives with higher HP & torque by avoiding quick holeshots and taking it easy on the throttle. Our warranty does not cover applications over 300HP.

Tech Support

[dverkest]

I’m curious to learn more about your 350 build. I recently built up a 350 for my 1988 18’ Bluewater open bow w/alpha 1 outdrive. I took a rebuilt 350 and installed an Edelbrock Performer intake, Eldelbrock EDL-1409 600 CFM marine carb, Edlebrock EDL-2102 cam, K&N Marine Air Cleaner, MSD Marine Coil and installed a fresh water cooling system. I’m guessing it is producing around 300 HP since it has the same spec as an Edelbrock crate engine that is advertised at 310 HP. Now that rating is based on running on headers and since my exhaust it not through the hole but through the outdrive, I’m sure I’m losing HP through the exhaust. I tell you what; this set up is awesome. I’m still running the original alpha one with 1.62 ratio (original engine was a 200 HP 5.0), but after replacing the 19 pitch prop with a 21, I’m spinning 4800 RPM (WOT) @ 60 MPH. The boat plains right away even when pulling skiers.
Now the outdrive is no longer engaging into reverse, so I’m looking at replacing it with a complete SE106 with the 1.47 ratio.