Old school l 88 454 mags, needing more HP
#1
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From: Vancouver Canada
I have a stock formula 1988 292, with 454 mags. I would like to get better power and sound out of these motors. All I am interested in doing is maybe piston upgrades and cams possible heads if I need to. Trying to do it on a budget. Not looking for a ton of power but at least a lumpy cam to sound perform better, and better compression, anything more than what it has because they still run strong, but I think they are tired. Looking for suggestions, ideas?
Thanks
Thanks
#2
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From: Orlando, FL
Might be a good idea to do a compression/leakdown test on them first, if they're "tired" then you might push them over the edge with trying to get more HP out of them. If the above is all good, maybe some fresh ignition parts, fuel filter, and a carb rebuild?
If you're on a budget, then a good running engine is way better than a blown-up one.
If you're on a budget, then a good running engine is way better than a blown-up one.
Last edited by DrFeelgood; 10-27-2025 at 12:30 PM.
#3
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Exhaust is usually the first step since any flow increase made with cams/heads/intake is pretty much negated by restrictive factory exhaust. Exh alone can get out of budget quickly especially if it's times 2. Exh will however give you some of that sound you wanted.
Lumpy cams sound cool as hell, but if running wet exhaust, they can cause water to get sucked back into eng. If you want to go dry exhaust, then you can go lumpy to an extent, still need some good mid-range to get on plane.
High compression is a great power adder but since boat engs are always under a heavy load, detonation can be a serious problem if other mods are not done to support it. Also need to know if you can get high-octane on the water. May need to start carrying cans of octane booster around with ya.
Once you open up an old eng, things start adding up fast. Prices on every little thing have gone up.
There's a good chance you can change boats to something more like you wanted for less money.
Think Docs advise is right on.
Lumpy cams sound cool as hell, but if running wet exhaust, they can cause water to get sucked back into eng. If you want to go dry exhaust, then you can go lumpy to an extent, still need some good mid-range to get on plane.
High compression is a great power adder but since boat engs are always under a heavy load, detonation can be a serious problem if other mods are not done to support it. Also need to know if you can get high-octane on the water. May need to start carrying cans of octane booster around with ya.
Once you open up an old eng, things start adding up fast. Prices on every little thing have gone up.
There's a good chance you can change boats to something more like you wanted for less money.
Think Docs advise is right on.
#5
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From: On A Dirt Floor
#6
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From: Connecticut
454 Mag engines come with all "the good stuff" from the factory...including forged pistons, steel cranks, square port cylinder heads and 4 bolt main blocks....A nice upgrade to Mag Engines is to bolt on a pair of Weiand 177 superchargers. Mercury actually did this to some of their Mag engines right at the factory and called them the "Mercury 525SC". they ran great, and were very reliable engines. Maybe freshen up your engines with rings, bearings, valve job, ect....and find a used pair of 177's and go have fun !!!!
#7
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From: Vancouver Canada
#9
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From: Vancouver Canada
The super chargers look like the way to go, but how about cams? Im probably not going to touch exhaust, but if I do tear them down definitely hone the. cylinders all new rings and bearings to freshen them up. Valve job. Those chargers are hard to find used.
#10
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From: Bourbonnais, IL
I purchased a kit from Tyler Crockett to wake up my 454MAG. Cam, larger valves, and increased comp ratio by milling down deck of heads with new SM exhaust. Cost 7K but added- 90 HP to the motor, sounded great!



