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454 Magnum Upgrades?

454 Magnum Upgrades?

Old 05-11-2004, 06:49 AM
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Unhappy 454 Magnum Upgrades?

I have a 1988 Regal Velocity with 454 Magnum 365 hp & Bravo 1. Only 415 hours on the boat. I really have no idea what makes "Magnum" different from other 454's. Except the heads. Can anyone tell me more about the cam, pistons, etc. I do have a cracked head. Rectangle port with open chambers. Have not been able to find a stock replacement. Been told ChiefEngines and Teague have a "Bolt On" replacements with Inconel Values and Manley. Has anyone tried the heads? And what size do you suggest. 320 CC? Any help with orginal specs and any upgrades would be big help. Also, I have seen a lot of msg about rev limiters. Is there one on this boat. Oh yeah. I have no idea what Gen this is. IV, V, or VI. I think it is a IV. How do you tell?

Thanks so much. Need all the help I can get.
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Old 05-11-2004, 09:15 AM
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You have a good base engine to start with; 4 bolt block, GM Forged dimple rods, steel crank. Pistons I think are forged but someone needs to confirm that.
Heads, well since '88 their has been alot of advancements and actually the old square ports are not the best choice. Since you have one cracked, I would suggest going to a set of Merlin Oval Ports with a matched dual plane air gap intake. Boat engines don't see the kind of RPMS needed to take advantage of these heads. . .unless you put some CID under the heads to take advantage of the intake runner volume. You should be able to get a new pair of heads and intake for around $1600.

You do have a gen 4, great block for modifing. In the future you can get a stroker kit for the engine and go to a 500 incher if you so choose. The Merlins would still be suffiecent for this CID and the engine should make a ton of torque.

Old 05-11-2004, 04:21 PM
chuck21401's Avatar
Join Date: Feb 2004
Location: Annapolis, MD
Posts: 513

Check out this thread, I asked a similar question last week:

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Old 05-12-2004, 01:12 AM
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You do not have a rev limiter on your engine if it is stock original.
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