300+HP OMC V-6

THEFERMANATOR · #1 09-11-2007, 11:43 PM

As per a request by kamikaze. Here is the link to the article on how to build up a 300+HP JOHNNY-RUDE V-6 that will run on pump gas.

http://members.cox.net/aprilhorvath/...Project300.jpg

phester · #2 09-12-2007, 12:44 AM

.......skools write that?

THEFERMANATOR · #3 09-12-2007, 01:38 AM

STOKER over on SCREAMANDFLY.COM wrote it. Him and 2 or 3 other guys are regarded as the performance guru's of the OMC's over there, but dyno sheets don't lie. 307HP(corrected figure) on pump gas out of a basic engine put together from regular parts is pretty impressive by any means. That 2.7L that MJ just got on Ebay is a prime canidate for a build-up ;D. He's already got the bigger ports, and the tighter heads. Bore that sucker out to a 3.0L, and some mild porting. Strap it to the back of his V and hang on :o.

Skools_Dual · #4 09-12-2007, 02:03 AM

hey Ferm I did this to a late 86 140 bored it out to large bore and put finger ports in it then used 88 225 upper intake with boysesn reeds and then the upper carbs off a 1990 evinrude 225. the heads were shaved 1/8 inch and wow that was one mean *** motor, she would fly. it had 180 psi per cylinder and i used a larger V6 foot. wish i could have dynoed. i bet she made 175 + HP and it was on a 18 ft boat lol. that boat ran around 60 plus mph.

THEFERMANATOR · #5 09-12-2007, 02:35 AM

I'm content with my early 85 140 looper. It's got 155 lbs of compression with just .020 over pistons, 87 carbs with some minor porting in the exhaust. Push's a heavy 18 foot bowrider to almost 50 with a 19 pitch VIPIR. I had it up to 53 with a 4 blade POWERTECH prop once, but the chine walk was uncontrollable.

bigshrimpin · #6 11-13-2007, 12:57 AM

Skools - Did you have a machine shop cut the finger ports or did you do this yourself? I've got 4 merc 2.0L blocks sitting in my garage and 3 or 4 sets of 2.0L pistons and rods. Supposedly you get some really big gains adding fingerports to the 2.0L mercs. . . . I don't really care about blowing anything up.

THEFERMANATOR · #7 11-13-2007, 01:01 AM

T-REX over on screamandfly is supposed to be pretty good with the 2.0L MERC's. Didn't know if you've heard of him before or not. I personally miss my 2.0L MERC for the milage. I had one on the back end of a 18' bass boat that would only burn 4 GPH at a 35-40 MPH cruise, wish my 2.5L could do that on my flats boat :'(.

Skools Out · #8 11-13-2007, 01:39 AM

neighbor did it in his machine shop

bigshrimpin · #9 11-14-2007, 02:08 AM

Thanks Skools and FERMANATOR! TREX gave me a lot of the info for the 2.0L. I'm wondering what it'll cost me for the port work and if it's worth it. I've got the long tuner, carbs, horizontal front, and 40 amp ignition . . .

This was TREX's advice for a 2.0L stump puller.

http://forums.screamandfly.com/forum...t=stump+puller

Find sum small venturi carbs(135's), cut 7/16" fingerports in the block...1- 1/2" long X 7/16" and .010 below boostport roof...widen exhaust port to 70% diameter ov the bore...don't raise the port roof!!...smooth out the exhaust port on the inside...DONOT cut out the exhaust chest!!..."D" port piston, and cut the Fingerport holes to match the FP's in the block...cut heads to 33ccs(2.0 heads) for pump gas...the more comp, the more pull, but the more comp, the more octane ness...The pro max tuner will let it turn up a few more rpm, but the LONG tuner will give more grunt...The Large, 40 amp wheel will actually help keep the momentum once U git it goin...2:1 geers...I have one like this on a 23' aluminium work boat, and with a 19pitch prop, it will carry the same load the 225 3.0 does on a twin boat, but juss not as fast!!..