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kragar
09-23-2009, 07:32 PM
I bought a 1997 baja hammer and the guy told me it had the magnum in it. The original spark arrester on top of carb has been changed. How do I tell the difference between them. The vin on the block back by the transom on the drivers side is 10237797. There is also a J286.
Also what is max RPM on the 454 and the 454 mag?
FastDonzi
09-23-2009, 08:37 PM
Most 454's make peak power around 4500-4600rpm, red line is about 5000rpm. if you upgrade to a better rotating assembly you can move both figures up a good bit. I'm a believer in having a bullit proof bottom end anyway, I hate to worry that if I run it really hard for 5 minutes it's gonna give up. I want one that after running hard, wants more....
MOBILEMERCMAN
09-23-2009, 08:47 PM
In '96 and '97 454 magnums had Weber carbs. Serial number group is OF801700 thru OK999999 The following year it was an MPI. If it is an original motor there will be a tag on the block near the starter.
Airpacker
09-24-2009, 09:02 AM
welcome to Serious kragar. Glad you came over for a visit.
Knot 4 Me
09-24-2009, 01:10 PM
If the intake is still original, you can tell the difference between the magnum and standard 7.4L by looking at it. The magnum will have a higher rise manifold than the flat truck style manifold on the 7.4L. Max RPM on the 7.4L is 4,600. The magnum was either 4,800 or 5,000...can't remember off the top of my head. Later MPI versions of the 454 Mag were 5,000 RPM..
kragar
09-24-2009, 07:28 PM
Well it has a weber carb on it but the intake is steel. The tag down by the starter is k154878.
Trim'd Up
09-25-2009, 07:43 AM
If the intake is steel it is a 330hp not a mag. The mag intakes look like a Edelbrock Performer compared to the flat iron intake.
Griff
09-26-2009, 02:55 AM
The magnum engines also have rect port heads. Check the head casting numbers on www.mortec.com
DAREDEVIL
09-26-2009, 09:47 AM
Well it has a weber carb on it but the intake is steel. The tag down by the starter is k154878.

Should be a 330 !! No mag.

RPM : 330 max 4800 and 454 mag. 5200
kragar
09-26-2009, 06:04 PM
Well had boat out today and could get it running 67 by myself running 4700 rpm. Gotta pull the drive as I am pretty sure the gimble bearing is shot. Had a vibration and noticed the gear oil resivoir was milky. Gonna pull the drive and check everything out. Boat sure does get light running wide open. Feels great!