Which one would you choose and why? 502 Mag has 415 hp and open cooling, 496 Mag HO has 425 hp and closed cooling. Besides that, what is the good and bad of these two engines?
502 Mag vs. 496 Mag HO
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khots
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Referring to the exhaust. Also, I beleive the motor is lighter than the stock 502.............. and yes, you can put the same exhaust to the 502. (talking about aftermarket exhaust if It's not clear, sorry)
I had a boat with a 502 mag, blew it up, replaced it with a 454 mag and did the exact same rpm and speed. I also had a boat with twin 496 mags and one with 496ho's and i'll tell you one thing, when your stuck, forget about fixing it, the damn things are to computerized. I was stuck once because a manifold temp sender was reading improperly and it put the boat in guardian mode, pain in the ***.......had to wait 4 days for someone to come with a computer to find out a $20 part was chitting the bed....... I'll take a 502 or 454 anyday, salt or not, as long as you can flush it..... Just my opinion...........
NO !!!!!cuda said:
502 is it's own block. It has siamesed bores to handle the 4.47" + bores.
454 is non siamesed and handles 4.25" bores. You can take these to about .100" further but no where near the 4.47"
Same exterior size - same heads, exhaust, and etc, etc. But not the same engine block.
Oh, weight is negligable between the two.
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My 502 Mag longblock was $100 CHEAPER than the 454 Mag longblock. Guess I screwed up. I shoulda bought the 454.cfm said:
Yes, you are correct. Pretty much everything but the pistons.
454 and 502 have same stroke and can use same crank if balanced for each application.
same rods/heads/cams/etc,etc,etc
That's the beauty of these and thus what keeps cost down since no real unique pieces have to be manufactured other than blocks. Typically The more volume something is made the easier to make it cheaper.
454 and 502 have same stroke and can use same crank if balanced for each application.
same rods/heads/cams/etc,etc,etc
That's the beauty of these and thus what keeps cost down since no real unique pieces have to be manufactured other than blocks. Typically The more volume something is made the easier to make it cheaper.
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No toe stepping............. I just think the 454 mag with aftermarket headers is a great option. about 420 hp is easily obtainable with that and an arrestor and pressure reg. Plus, it's a little lighter.
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Yes, negligable difference.BadDog said:
Anyway - what I'm thinking Dallasboats was saying is that if you buy say a boat with twin 454mpi's (prob cheaper than same type used /new boat with twin 502 MPI's) if you add aftmkt exhaust which lightens it and adds some hp, and add a couple of other smaller bolt on mods, you'll have same or little more power than factory 502MPI's.
So, I agree this is a consideration. Especially if price between a 454MPI boat is that much less than a 502MPI boat where paying for these mods still saves you a bunch of money.
If I'm wrong please correct me - but that seems logical to me.
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Another issue I haven't seen mentioned here yet -
How about top RPM's?
The old 454/502's were good for what, 5200RPM, I think?
While new 496's are electronic limited to 4600RPM, so, all thinks being equal in the drive/prop gearing set-up, the 502 is going to produce a higher top speed.
I ran into this problem after taking out a 496 stock motor - the top speed sucked in comparison to the same hull with a 502, even though the 496 is rated 425HP compared to the old 502's @415HP. While you would think 10HP more might be a positive, it actually ran slower due to lack of rev's, and you can't compensate by prop, as the 425HP isn't enough to push a bigger prop and make up the speed lost!
How about top RPM's?
The old 454/502's were good for what, 5200RPM, I think?
While new 496's are electronic limited to 4600RPM, so, all thinks being equal in the drive/prop gearing set-up, the 502 is going to produce a higher top speed.
I ran into this problem after taking out a 496 stock motor - the top speed sucked in comparison to the same hull with a 502, even though the 496 is rated 425HP compared to the old 502's @415HP. While you would think 10HP more might be a positive, it actually ran slower due to lack of rev's, and you can't compensate by prop, as the 425HP isn't enough to push a bigger prop and make up the speed lost!
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496HO runs 5000(same as 502mag) and the 496 standard runs 4800.BajaBoss232 said:Another issue I haven't seen mentioned here yet -
How about top RPM's?
The old 454/502's were good for what, 5200RPM, I think?
While new 496's are electronic limited to 4600RPM, so, all thinks being equal in the drive/prop gearing set-up, the 502 is going to produce a higher top speed.
I ran into this problem after taking out a 496 stock motor - the top speed sucked in comparison to the same hull with a 502, even though the 496 is rated 425HP compared to the old 502's @415HP. While you would think 10HP more might be a positive, it actually ran slower due to lack of rev's, and you can't compensate by prop, as the 425HP isn't enough to push a bigger prop and make up the speed lost!
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WOW!!!! A real live "GO FAST BOAT" thread. :a1: :a7:
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Blackhawk -
Merc service manual lists 496MAG HO as 4600 top RPM.
Maybe some will turn more, but mine wouldn't. I just assumed it was programed with T.E.L @ 4600, as it had never been "tweaked" at all electronically.
Merc service manual lists 496MAG HO as 4600 top RPM.
Maybe some will turn more, but mine wouldn't. I just assumed it was programed with T.E.L @ 4600, as it had never been "tweaked" at all electronically.
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Hell...my 496HO turns 5250......BajaBoss232 said:
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