magnum or not??
02-03-2011 | 10:53 AM
#11
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From: IL
Some of the carbed BIII's used by PQ had the forged internals (Merc manual : "7.4L Bravo Three engines with engine code UB with serial number OF1589289 and lower have forged pistons."). I have one of these in my '94 257. A long time Merc mechanic told me these also have forged cranks, but I have not verified that and the manuals says cast.
02-03-2011 | 11:14 AM
#12
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From: Music City
02-04-2011 | 07:45 AM
#15
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From: Central IL
You can quickly tell by the intake manifold if it is a MAG or standard motor, assuming no one has replaced the intake. The standard 7.4L has the flat truck manifold on it and the MAG has the high-rise intake on it.
02-04-2011 | 08:14 AM
#16
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From: IL
02-07-2011 | 10:28 AM
#17
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Actually, the "Performance Tuned" 7.4 carb motors had the alum high rise from the mag on them, but were the 300 hp motors. Done to increase low end/midrange torque in those motors.
02-07-2011 | 01:11 PM
#18
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From: Central IL
02-07-2011 | 02:07 PM
#20
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From: Central IL
