WHAT TO USE ON A ZZ502

[scorpionking]

ok guys, im new to blowers, i am buying a gm crate zz502 setup and want to put a blower on it, but leave the motor as stock as possible. what blower would be right for me to make a dependable motor but add some umph to my speed and midrange. i have a 21 ft jet

[502procharger]

i am no expert, but i know the freeze plugs, cam and head gasket need to be changed, blower or not for marine use.

[tsnave]

Hey Scorpion!
I have an awesome EFI/ProCharger/SuperChiller setup for sale that will fit real nice under your hatch. All is new! E-mail me at taevans@swbell.net if you are interested...

[cyclone]

the ZZ502 has 9:1 CR. You're gonna want to change out the pistons to lower the CR if you want to run some serious boost. It does have a good forged steel crank though.

[scorpionking]

mike, i am really only looking at maybe 3 lbs of boost. some folks have told me go with a 671 since it wouldn't have to work as hard,but is that overkill??

[cyclone]

most folks i know will opt for a small B&M blower in an application like yours.

[502procharger]

I am just curious why you would spend all that time tinkering and money to only go with like 3lbs of boost. 3lbs of boost really will not do that much for performance. If you are spending the time and money build it to handle more boost then just run less if you want. You inevitably will want to go faster and it will really piss you off if you have to build up your motor again just to run more boost reliably. Just a thought

[scorpionking]

that makes sense. if i went to a lower compression piston set up what would be the max boost i could add?

[paradigm shift]

Have you bought the motor yet. If not you might consider a long block with aftermarket heads with larger combustion chamber size to lower compression ratio. If you are going to run it in a boat and blown I would pull it down and check the clearances. If going blown I would pay particular attention to cylinder wall clearances on pistons and ring gaps. You will want to pump up the boost we all do! A cam change would help performance. wink Just my .02

[truckboss]

hey due before you buy the crate motor not that its a bad one,for about the same money you can put together something with all the good parts and will last longer.look at speedomotives web site before you buy.just a thought.

[scorpionking]

ok, any idea what that web site name is?

[Infomaniac]

scorpionking - Check your PM :)

[Craig]

I run 9.3 to 1 and 7 pounds boost, but I run av-gas all the time. You could run 5 pounds and keep the total timing conservative, say 30 degrees and be OK. You should upgrade the valves and the head gaskets at a minimum.
Craig

[scorpionking]

well, everyone has told me at a minimum to switch out the heads, anybody have any suggestions on a good aftermarket fit for what i am wanting to do??

[502procharger]

I have a set of merc 500hp heads with Manley severe duty valves, springs and retainers. Mild port work $800.00 i also have the dart 500hp intake $200.00. Shit for that matter i have a ready to drop in BBC 502 with 475 hp. like 125hs strong and clean. With all accessories, exhaust, electrical, ignition, ECT. $5000.00 . you could pull 600 reliable hp easy with an intercooled supercharger of some kind.

[Freak]

S****Omotive.com - don't go there. Notice how parts like the crank are no names. Made in China. Boat's are to hard on parts.
[ March 12, 2003, 04:33 AM: Message edited by: Freak ]

[Craig]

If you're running GM square port heads your OK for the horsepower your looking to make. In my opinion, the aftermarkets heads aren't worth the $2000 for the gain when you're looking in the 600-700 hp range (blown, only though). Put some good valves, springs, etc. in the GM's and go. Now if you had to buy heads anyway, Brodex BB-2's. Again, IMHO. Friend of mine bought a 540 shortblock from Speedomotive. Had nothing but trouble. Wrong oil pump, wrong dampner. Always destroying bearings, found oil passages blocked with debris that looked like they were in there from the start.
[ March 12, 2003, 02:55 PM: Message edited by: Craig ]

[Just Tool'n]

I was talking to a buddy the other day about a guy who put a pair of zz502 in an old 80's era scarab, like 35footer & 10,000lbs. Can not make the motors last. I know these are neat motors but you could buy a pair of teague custom marine motors for a little more money. Then you have an engine that is built for marine duty use, instead of a car motor that is going to work itself to death.

[502procharger]

I have to agree, i think for the same money someone could build you a better motor made to take the heavy marine use. Infomaniac has built a few motors for people and from what i have heard he is very good and reasonably priced. You may want to pm him. Good luck

[TOOMNYTOYS]

I BOUGHT A INDMAR 502 MOTOR LAST SUMMER AND THIS WINTER PUT SERVERE DUTY SS VALVES,SS VALVES,ROLLER ROCKERS,CAM STUD CONVERSION,HIGH PERFORMANCE GASKETS WITH A 871 WITH A SUPER CHILLER. IT MIGHT HAVE COSTED A LITTLE MORE THIS WAY BUT I KNOW I HAVE THE RELIABILTY OF GOOD SAE MARINE INVERIOMENT PARTS. ORGINALLY WANTED TO JUST PUT IN A 671 BUT AFTER LONG AND LOTS OF THOUGHT I DECIDED I WOULD TWIST IT TO MUCH FOR RELIABLITY.YOU CAN SEE PICS IN THE GALLERY OF IT SORRY I DONT KNOW HOW TO POST TO FORUMS.