How do you tell if a 454 is a mag or not?
11-01-2009, 11:46 PM
#1
Registered
Thread Starter
Join Date: Sep 2009
Location: Chatham.Ontario
Posts: 268
Likes: 0
Received 0 Likes
on
0 Posts
How do you tell if a 454 is a mag or not?
The boat is a 1991 larson senza and I was wondering how i can tell if the engine is a 454 mag or just a 7.4L?
11-02-2009, 08:41 AM
#6
Registered
Join Date: Aug 2007
Location: Port Deposit, MD
Posts: 622
Likes: 0
Received 0 Likes
on
0 Posts
Metal tag on motor is ORANGE (rather than purple).
I think..............
It should be fairly well marked. That vintage, if it just says "7.4L Bravo I" on the spark arrestor, it's NOT a mag.
I think..............
It should be fairly well marked. That vintage, if it just says "7.4L Bravo I" on the spark arrestor, it's NOT a mag.
11-02-2009, 09:57 AM
#7
Registered
The intake manifold is raised higher towards the carb ,where a 330 oval port has a more flatter intake manifold,if parts (manifolds )has been swapped on engines its difficult to say ,but there is a way to see if the heads are retangular or oval port , on the end (front/rear side ) of each magnum/retangular cilinderhead there is a bump in the castingline ,all steel retangular port heads have these ,,bump,, where the ovals have a flat castingline ,see if you can find a magnum head ,and look for the bump you,ll see what I mean .
11-02-2009, 10:24 AM
#8
Registered
and to confuse things a bot more the 454/ALPHA available for a few years were called Magnums even on the airclaner but were just plain ole 330s not real Magnums.
11-02-2009, 10:53 AM
#9
Registered
Join Date: Jul 2005
Location: CT
Posts: 571
Likes: 0
Received 0 Likes
on
0 Posts
There probably is a designated letter or number, or combination of such, that would determine whether it is a Mag or not. However I don't know what it is. If you give the number to a dealer they will be able to tell you. You may even be able to look it up on-line.
Charter Member
