GM Performance Engines 454 -vs- 502
06-05-2012 | 12:44 PM
#11
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From: Saint Louis, MO
Wow! Great input, great community here on OSO!
MLD THNDR & ENDVR32 - I agree w/ you guys, too late in the year and too little savings. The spare won't hurt me either, crate, here I come, Thnx. I dream all winter about these summer weekends!
RAYLAR - Fantastic advice, old set-up was fine, 5# boost on a deck boat is plenty, it doesn't get hammered. Mention of the "balancing act" is golden. I'll research the internal / external aspects of the ZZ502 -vs- the components on my stock 454 mag and may have a few questions to throw out here.
Cometic head gaskets for sure. I need to research head gasket thickness and what effect they might have on the "fixed" rocker adjustment on my stock (119cc?) 454mag heads. Fortunately, new block should hold the 9.800" deck height closely.
While I'm swapping the pan on the new crate I'm open to an oil pump upgrade if anyone has a preference on what's best for an "engine oiled" (non-sc) M1 procharger.
Thanks all ....
MLD THNDR & ENDVR32 - I agree w/ you guys, too late in the year and too little savings. The spare won't hurt me either, crate, here I come, Thnx. I dream all winter about these summer weekends!
RAYLAR - Fantastic advice, old set-up was fine, 5# boost on a deck boat is plenty, it doesn't get hammered. Mention of the "balancing act" is golden. I'll research the internal / external aspects of the ZZ502 -vs- the components on my stock 454 mag and may have a few questions to throw out here.
Cometic head gaskets for sure. I need to research head gasket thickness and what effect they might have on the "fixed" rocker adjustment on my stock (119cc?) 454mag heads. Fortunately, new block should hold the 9.800" deck height closely.
While I'm swapping the pan on the new crate I'm open to an oil pump upgrade if anyone has a preference on what's best for an "engine oiled" (non-sc) M1 procharger.
Thanks all ....
06-05-2012 | 02:45 PM
#12
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From: Houston, TX, USA
Many years ago I bought a 502 crate shortblock. At that time I was planing on turbocharging the motor. As I did my researching after buying shortblock I found out I was going to have to change cam and open up my clearances for a motor under boost and running at 100 degree water temps. I ended just leaving the short block in garage and starting fresh with all the right parts. I no longer own the motor but before I sold it I was running 10 lbs of boost thru it and now the new owner has run it hard all last year with no problems.
06-05-2012 | 06:13 PM
#13
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From: Riverview, Michigan
Change the camshaft and any steel freeze plugs for brass in the ZZ502 block for sure and if your 45 has a counterweight on the flywheel and balancer, make sure the 502 has the same before you install yours other wise the stock internal balancer on the 502 if its there will accept your pulleys and the internal balance flywheel (without counterweights) are easy to find. DON"T put external balance (counterweighted) balancers or flywheels on internally balanced engines that come with internal balance flywheels and such , you will destroy the rotating assembly and the engine. The forged internals of the ZZ502 should take mild supercharging just fine when the air fuels are adjusted correctly and just use a .060" Cometic gasket min. to keep the compression in line.
Also keep in mind that GM performance standard engine or block warranties do not cover that part when used in marine applications like they do for the same part in vehicle use.
Best Regards,
Ray @ Raylar
Also keep in mind that GM performance standard engine or block warranties do not cover that part when used in marine applications like they do for the same part in vehicle use.
Best Regards,
Ray @ Raylar
06-05-2012 | 06:18 PM
#14
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From: Riverview, Michigan
The ZZ502 does have an externally balanced crank. Therefore, it does require both the flywheel and balancer to match. My ZZ502's have been internally balanced, so I no longer new my flywheels or balancer's. If you go this route and need some components, you know where to find me.
06-07-2012 | 08:08 AM
#17
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From: central NY
Raylar and Rotax454..... +1
I will add.... I ran a ZZ502 NA for 4 years in my 23 Nova, and ran it hard, and left the ZZ cam in place. ZZ cam is allot like the old hp500 cam so I kept the idle up and snapped the throttle a couple of times after idle/dock time. My ZZ ran great, durable as he!! and very reliable.
I will add.... I ran a ZZ502 NA for 4 years in my 23 Nova, and ran it hard, and left the ZZ cam in place. ZZ cam is allot like the old hp500 cam so I kept the idle up and snapped the throttle a couple of times after idle/dock time. My ZZ ran great, durable as he!! and very reliable.
06-08-2012 | 08:17 AM
#18
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From: Saint Louis, MO
Everyones input has been very helpful and valued.
I'm still buying pieces to assemble the 502 Mag (ZZ).
Any advice on:
*Oil pump for an engine lubed (non-sc) procharger. Benefits / downfalls in using high volume and/or high pressure? Use the pump that comes w/ ZZ502 short block?
* Mild upgrade to stock (454 mag) mercruiser exhaust manifolds. I wouldn't mind losing some weight, and gain a little flow. They would have to be direct "plug -n- play". Dana has a set that looks interesting, any preferences / warnings? I posted this question in the Eliminator section but those guys over there won't talk to someone with a handle like "Low Buck" who runs a deck boat......
Thanks all,
No one of us is as smart as all of us
I'm still buying pieces to assemble the 502 Mag (ZZ).
Any advice on:
*Oil pump for an engine lubed (non-sc) procharger. Benefits / downfalls in using high volume and/or high pressure? Use the pump that comes w/ ZZ502 short block?
* Mild upgrade to stock (454 mag) mercruiser exhaust manifolds. I wouldn't mind losing some weight, and gain a little flow. They would have to be direct "plug -n- play". Dana has a set that looks interesting, any preferences / warnings? I posted this question in the Eliminator section but those guys over there won't talk to someone with a handle like "Low Buck" who runs a deck boat......
Thanks all,
No one of us is as smart as all of us
06-08-2012 | 08:34 AM
#19
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Posts: 8,439
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From: yorkville,il
the gm 502 crate short block would be a good choice,i dont know if it comes with a oil pump or not,i reccomend useing a mellings high volume pump,and your origional merc pan,it should be an 8 qt pan.
06-08-2012 | 10:08 AM
#20
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From: central NY
I'd say your exhaust choice would depend on 2 things - horsepower and cam choice. The ZZ cam is somewhat reversion prone. That said, I ran the stock merc 7.4 exhaust for a season with no problems, but as mentioned I'd crack the throttle a couple of times after idle time, to clear things out. Year 2 of the ZZ I switched to Revolution Marine exhaust because they gave more "rise". Inexpensive exhaust system but did seem to give a little more zip in mid range, lot lighter too. If you can find a good set of used KE's that would be the titz. And if you wanna play it safe, consider a different cam. Bob Madara of Marine Kinetics would be the guy to go to for a cam, and just pain ol' good advice..... 585-654-8583.
