all 454MAG Created = ?
06-06-2002, 01:16 PM
#1
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all 454MAG Created = ?
Dear Board Mercruiser Guru's
:
I have a 1990 454Mag (per Serial #).
Decided I should ID cam.
Appears to be a stock GM Marine cam #14096209. A 300 hp cam
? (not what it had been represented as to me).
It does seem to have rectangular port heads though Casting # 1409**8 (**=numbers bloted out by coffee stains on note book- will get again).
Question: Are all 454MAGS created equal?
I would like to throw a better cam and intake on this unit (it is in great shape) but am leary that the heads and or bottom end might limit success.
Can anyone tell me what is different between a 300hp (apparently what I have) and the 425hp MAGs and can I get there from here without different heads? Can't seem to find anyone local who knows.
Thanx for the Help,
Confused in Indiana......
:I have a 1990 454Mag (per Serial #).
Decided I should ID cam.
Appears to be a stock GM Marine cam #14096209. A 300 hp cam
? (not what it had been represented as to me). It does seem to have rectangular port heads though Casting # 1409**8 (**=numbers bloted out by coffee stains on note book- will get again).
Question: Are all 454MAGS created equal?
I would like to throw a better cam and intake on this unit (it is in great shape) but am leary that the heads and or bottom end might limit success.
Can anyone tell me what is different between a 300hp (apparently what I have) and the 425hp MAGs and can I get there from here without different heads? Can't seem to find anyone local who knows.
Thanx for the Help,
Confused in Indiana......
06-06-2002, 01:55 PM
#2
To my knowledge the carbed 454mag was a 365hp motor. Not sure where you are getting the 425hp figure from??
The way to tell if it is a mag motor is to check out the heads....They WILL be Rectangular Ports. If you don't want to pull the intake, pull a valve cover....it shoulf say "HI-PERF" in the casting.
If they are oval ports, then you have a base 330hp...or under...(300hp or 310hp) motor....in which the bottom end is made of cast components.
The way to tell if it is a mag motor is to check out the heads....They WILL be Rectangular Ports. If you don't want to pull the intake, pull a valve cover....it shoulf say "HI-PERF" in the casting.
If they are oval ports, then you have a base 330hp...or under...(300hp or 310hp) motor....in which the bottom end is made of cast components.
06-06-2002, 02:12 PM
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I have heads off. They do have "High-Perf" cast onto them.
454 Mag-365hp was what I was told the motor was, but this
cam number has me a little concerned.
Was thinking of putting the stock Merc (neh Crane) 425hp cam into it with a different intake. Wanted to try and confirm what I had first though.
454 Mag-365hp was what I was told the motor was, but this
cam number has me a little concerned.
Was thinking of putting the stock Merc (neh Crane) 425hp cam into it with a different intake. Wanted to try and confirm what I had first though.
Check again....
06-06-2002, 02:52 PM
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Thanx for the imput, I feel much better now.
Any opinions on the 425hp Merc Cam Grind?
228/236 and 0.530/0.551
Or is there a favorite for mild-warm overs?
(Only thru-hull currently for exhaust).
Any opinions on the 425hp Merc Cam Grind?
228/236 and 0.530/0.551
Or is there a favorite for mild-warm overs?
(Only thru-hull currently for exhaust).
06-06-2002, 03:05 PM
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"it shoulf say "HI-PERF" in the casting. "
actually many oval and small oval (peanut) port heads are also marked hi-perf specifically for example casting #'s 14081052 and 14092359 from the latet 80's, These were generally truck heads but used by merc on many of the 330's
you have to look up the casting number, HI-PERF means nada
actually many oval and small oval (peanut) port heads are also marked hi-perf specifically for example casting #'s 14081052 and 14092359 from the latet 80's, These were generally truck heads but used by merc on many of the 330's
you have to look up the casting number, HI-PERF means nada
06-06-2002, 03:24 PM
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06-06-2002, 03:27 PM
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If you have the heads off....., then Screw the casting numbers. Are the ports (intake side) square OR round??
The ports will tell you!.....unless someone (previous owner) put Mag heads on a non Mag motor....but i doubt it...nordicheat says the cam #'s are from the mag motor.
you shouldn't have anything to worry about.
The ports will tell you!.....unless someone (previous owner) put Mag heads on a non Mag motor....but i doubt it...nordicheat says the cam #'s are from the mag motor.
you shouldn't have anything to worry about.
06-06-2002, 03:27 PM
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for older gen V and mk IV engines like yours try http://www.mortec.com/bbc.htm
good info on location and block markings there to
good info on location and block markings there to
