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1998 502 update options. What would you do?

Old 04-26-2020, 09:13 AM
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Default 1998 502 update options. What would you do?

Hello guys. Bought a new to me 1998 Cobalt 252 with a 502 and Bravo 1..

Engine shows 297 hours, but is 22 years old.and I want to make sure I don't have issues with it this season.

I am planning on upgrading the engine for next year. Not enough time to do this season, but will be looking to achieve a naturally aspirated 500 HP and 65 MPH. I already have the Hardin Marine Seaward exhaust from my previous boat. (bought this because I didn't plan on buying a bigger boat, and the previous engine was only a 7.4L, so the Seaward was a perfect fit. And still is for this season. Not so sure with the planned upgrade next year because they claim it's good up to 415 HP)

The boat does have captain's call exhaust, but I am seriously considering eliminating it and blocking off the opening when the engine comes out. I like the sound, performance and better cam options with a longer exhaust riser.

Knowing that I will be getting a new cam, lifters, push rods, rockers, etc.. next year, I don't want to buy anything unnecessarily..

So, what would you do?

option #1- Get the stock injectors sonic cleaned and flowed. Install an adjustable fuel pressure regulator and the better Gen IV flame arrestor. Cost around $600+

option #2- Eliminate the Merc EFI and go carb. Cost around $1000+

option #3- Eliminate the Merc EFI and go with the Holly sniper. Cost around $1200+

My only concern right now, would be if I go option #3 that I need to install O2 sensor bungs to run it this season.

Season is approaching fast and I need to act soon. Thanks for any help you guys can provide.



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Old 04-26-2020, 09:18 AM
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I'd sell off the 502 and get this.

https://www.shafiroff.com/chevy-pump...wg-twisted.php
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Old 04-26-2020, 10:07 AM
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If it runs good, leave it alone until you decide on your upgrades
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Old 04-26-2020, 10:21 AM
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No serial number but being a 98 would guess its a MEFI 3 with cool fuel. My 502 repower uses a MEFI 3 and cool fuel and I have 500hp
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Old 04-26-2020, 04:49 PM
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Have injectors serviced by Bup and call it a day..

Chris
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Old 04-26-2020, 05:20 PM
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Originally Posted by GPM View Post
If it runs good, leave it alone until you decide on your upgrades
It's a new to me boat, so I don't have much to go off of. Preventative maintenance.is key for this year. Cables, Impeller, thermostat, plugs, cap, rotor, wires, filters, hoses, fuel system. You get the idea

Originally Posted by AllDodge View Post
No serial number but being a 98 would guess its a MEFI 3 with cool fuel. My 502 repower uses a MEFI 3 and cool fuel and I have 500hp
0L017470 should be MEFI 1. Does have cool fuel. What did you change to get 500 HP?
Originally Posted by sutphen 30 View Post
I'd sell off the 502 and get this.
If I could get $10k for my stock 502, I'd be all over that. Does seem like a great deal for the price.

Originally Posted by Blueabyss View Post
Have injectors serviced by Bup and call it a day..

Chris
1 vote option #1. Thank you

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Old 04-26-2020, 05:46 PM
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0L017470 should be MEFI 1. Does have cool fuel. What did you change to get 500 HP?
Mine was bored .030 to make it a 509 and I didn't do the build, I paid to have it done.
Being a MEFI 1 should be able to obtain same power or even more, just depends on how far you want to go. I wanted mine to be able to run on 89 octane so this can limit overall power

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Old 04-26-2020, 06:36 PM
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Go the easy route. Simply clean and flow test the injectors, basic service, fluids/filters/oils/lube etc and run it. I would not bother with a new fuel pressure regulator. Less than 300 hours on the motor is not that much. I'd run it as "old reliable" and have fun with it.
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Old 04-27-2020, 06:18 AM
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have injectors flowed and cleaned, call it good . I see injectors that flow low from these 20+ year old motors when I do them and hear/ see horror story's of melted pistons , lost seasons, etc. Smitty
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Old 04-27-2020, 07:58 AM
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Had BUP just do my injectors from our 2002 496HO-MAG w/210hrs. I'm sure I will recover the slight RPM loss I had. Photo before service.



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