OMC 3 Cyl expansion Chambers

[850cc racer]

Hey Johnson racer, what record are you going for?

[johnsonracer]

I want the New Zealand F3 speed record.

Currently its held by a Hydro with a 1650cc inboard. A tunnel has gone 92mph in NZ in a kilo. No one thinks I can do it, but I'm sure you guys and around the world are breaking the 100mph with tunnels.

[johnsonracer]

Could some one tell me exactly what I have here?? It only has one bridge in the exhaust, so two big square ports...

Should this be the engine I build up?

[Tim Kurcz]

That's a pressed sleeve OMC factory Mod-50 block and exhaust side system. Do you have the front end and hemi head also? There's your kilo engine if you can get the rest of the parts.

[johnsonracer]

I got everything yes. The only problem with it is someone carved the exhaust too much and broke the aluminum bridge so I will need to get that repaired.

Also from memory they plated with the port heights too much and turned it into a dog....

Do you or anyone have a port map of it to make some new sleeves?

[Tim Kurcz]

From memory, the port map was published on Fast Fred's "secrets of the OMC Mod-50" thread. If you can't find it, send him a request.

[Fast Fred]

5.050 from crank center, a lot of chamfur on the top, like a fixed power valve.
1 3/16" Mod50 carbs be best for a kilo

sleeve part number , L.A. sleeve FL041ob

[Tim Kurcz]

Hey Fred,

Looks like you've got a new sleeve there. Did LA have them in stock?

[johnsonracer]

Hey Fred, thanks heaps....

I also need the heights for the other ports.... Someone really went to town on this motor...

Was brought from Aussie

[Fast Fred]

i made a trade a ways back for a copy with all the specs,
lookin at yours for what i can see, looks factory. gots to run.