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502 rebuild

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Old 10-18-2018, 12:10 AM
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Wink 502 rebuild

I bought a Mark VI 502 to replace my 92 454, looking to build it up to around 600HP. This is my first build so please bare with me on my inexperience. Would like to keep it dependable and fast, best of both worlds! Still trying to figure out stock head cc on 088 rectangle port, what cam to go with and how to figure out cam lift and duration for a motor build. planning on having head work done just donít know what to have done yet🤔. Looking for a build sheet to work off of and any suggestions or criticism. Will be purchasing new cam, pistons and possibly new heads. Have about 5K to work off of. 509 sounds good but no diffident direction yet. Thanks
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Old 10-18-2018, 01:16 AM
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What do you have for exhaust?? Intake manifold?? Carb??? If you need all them, used parts will be around $2500 and new parts would be around $5000
Even if you already have good exhaust, your 5k budget is most likely not going to cut it for a full rebuild.
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Old 10-18-2018, 06:55 AM
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Thanks Griff looking at Arizona speed and marine intake if I keep the EFI system and either Dana or Lightning headers my budget wasn’t including headers Will be closer to 8-10 by the time I’m done. Plus still need to upgrade to dual steering stabilizers. It’s only money !
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Old 10-18-2018, 07:05 AM
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IMO don't waist money reworking the 088 heads, put it towards a set of good used or new heads......the Merc 525 EFI cam is a solid piece and will work fine with the stock dog bone lifters in the gen 6 block.
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Old 10-18-2018, 07:46 AM
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I made over 600hp on a 548 BBC with 088 heads but they did have some intake and bowl work done to them. Your easiest way to make that HP is with a good set of heads matched to a good cam.
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Old 10-18-2018, 08:23 AM
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Any recommendations on witch heads to go with, CC, valving and anything else I’m not thinking of. would like to stay away from anything China made. USA ����
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Old 10-18-2018, 08:27 AM
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There is a nice pair of heads in the swap shop right now.

https://www.offshoreonly.com/forums/...afr-heads.html
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Old 10-18-2018, 12:26 PM
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502. Comp cam. EQ heads basically box stock. 8.7:1 compression. Merlin x intake. Quick fuel 850. [email protected] This was through etops in full marine trim on the dyno. Had I used dyno headers like most it would easily be over 600. Also having sweepers or eickerts would have jumped power by 30+. Very happy with the builds and the boat runs phenomenal. Any questions let me know.

Mike
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Old 10-18-2018, 01:24 PM
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What are sweepers and eickerts, stock cam? and what CC is stock head on 502. Thanks again for all the help everyone was a rookie a some point ��
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Old 10-18-2018, 07:47 PM
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Originally Posted by 92Cole View Post
Any recommendations on witch heads to go with, CC, valving and anything else Iím not thinking of. would like to stay away from anything China made. USA ����
https://www.jegs.com/i/Brodix/158/2321011/10002/-1

https://www.profilerperformance.com/...ree-heads.html
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Last edited by hogie roll; 10-18-2018 at 07:59 PM.
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