secrets of the OMC MOD50's

[Fast Fred]

thare are three power heads, guna talk about the first one the 19s.
this is a Tradewinds motor,port exhaust standard 49ci case + .030
uses the long rods same size as the Big twin, thare are mod 50 rods,
the dif' bein the wrist pin hole, stock mod 50 rods run the big wrist pin and caged wrist pin bearing. the big twin rod is the best set up, thay make a kit to run the big wrist pin in the small rod hole with full complament bearing.
steal crank, the stock mod50 19s pistons are two ring dome style with finger port tranfur holes. the case it self is the same as the production case,
the rib under number three exhaust port is cut to let water run in to case , this moda ran no thermostat, did have a water pump, 6 amp alternater,
the exhaust exit is also cut to except the mod 50 exhaust plates.

the front 1/2 on this one has the same jog as the stock intake with 4 over 4
pedal reed blocks, the reeds also had two smaller reeds on top that sat sideways with three 1" 2bbl carbs. was lookin for 100-130oct avgas out of the box.

the Preface of the Owner Manual

" This motor has been engineered and assembled to give the professional race driver, who desires to have a motor with extra capability, a motor which incorporates very high performance with quality and workman ship."
thares more but to the point
I've heard alot about how much hp this moda made on gas, 200hp, 150hp, 135hp, not !!!!!!!!! like it or not 100hp-105hp @7200rpm

[Fast Fred]

ran this port map

[Fast Fred]

this is the FR-19S

[Fast Fred]

this is the 19S powerhead

[Fast Fred]

Next is the Manawa motor , got to take some pic of it,

[Fast Fred]

the second generation , after the 19s but before the 31M thare is but another
MOD50 case, vary fue were made, looks just like the 19s, but in side it is vary dif', just so happens, i got one, made about 10-12more hp than the 19s
we'll take a look at it,

[Trikki1010]

Nice thread Fred

Now whit happend to sum a dem numbers on da port map

[Fast Fred]

hay Trikki1010
them port hight are vary high
this is the reed block of the 19s

[Fast Fred]

hear we got a 56ci/49ci front 1/2 (same) and the 19s front

[Fast Fred]

not sure on this one, not a 19s , or a 31m, but for sure a MOD50

[Fast Fred]

hears another shot, hear we see the strait on front 1/2, 31m style, this uses ten pedle reed blocks, a full inline 5 over 5 semetrical block

[chynewalkr]

is that port map drawing to scale? If it is i could figure out the secret dimension

[Fast Fred]

on the port map, it's not to scale, if you got a Stinger or a Hustler or a 70hp on your lake boat, them hights ain't guna make you vary happy, but what is thare
would make more power , ( add the fingers at side tranfur hight, finger ports shoot more UP than out, through some timein in to the boost port, don't go nuts, work the right side of the exhaust port like on the map, no need to go the full exhaust port unless you got a MOD50 front 1/2 and carbs to put on

[chynewalkr]

I got a xflow v4 on my boat, so those maps do me no good Just having alittle fun wichya

[David_L6]

Which ones are the best?