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-   General Q & A (https://www.offshoreonly.com/forums/general-q-20/)
-   -   Most HP out of a 525 (https://www.offshoreonly.com/forums/general-q/359048-most-hp-out-525-a.html)

hogie roll 04-04-2019 11:15 AM
Originally Posted by MDG_Jason (Post 4672574)
We found really good gains with the 525 just by going to a big bore. With no other modifications other than a 4.600 bore and ECM tuning to correct air/fuel we picked up approximately 60hp over a stock 525. Final number on the dyno was 610hp. Stock 525s constantly make 550hp on our dyno. By no means claiming to be the highest number from a 525 but we were very happy with the gains
Are 525 blocks good for the 4.6” bore? Maybe it was Mike Tkach saying some are different.

MDG_Jason 04-04-2019 06:31 PM
Originally Posted by hogie roll (Post 4680325)

Are 525 blocks good for the 4.6” bore? Maybe it was Mike Tkach saying some are different.
We prefer and in this case used Dart blocks for these but have gone 4.600 many times on a stock block without problems. Currently doing a set right now for my personal boat which started life out as a pair of 500efis. Block should be magnafluxed if going to 4.600. The Dart block has room to go larger so there is a rebuild left. The stock block is definitey done at 4.600

F-2 Speedy 04-04-2019 06:45 PM
Originally Posted by hogie roll (Post 4680325)

Are 525 blocks good for the 4.6” bore? Maybe it was Mike Tkach saying some are different.
gen 6 502 block should be safe to 4.500 without issue, perfect for a 540....4.25 x 6,385 x 4.500

endeavour32 04-04-2019 09:14 PM
Originally Posted by Sydwayz (Post 4680313)
Pic from Mark Rinda at MER Performance in SC:

https://cimg7.ibsrv.net/gimg/www.off...8fd27f333.jpeg
What is MER doing to get 650 hp out of a 525? That seems to be the most HP I've seen someone claim out of these engines.

sutphen 30 04-05-2019 06:23 AM
Originally Posted by endeavour32 (Post 4680418)
What is MER doing to get 650 hp out of a 525? That seems to be the most HP I've seen someone claim out of these engines.
they're adding stickers.:D

tdbrickndirt 04-07-2019 06:00 AM
Originally Posted by endeavour32 (Post 4680226)
Did you ever re-dyno after the EFI was reinstalled?
not yet. I’ve been swamped with work. This week I’ll be putting everything back together etc. I’ll let you know once I have some numbers

Sydwayz 04-08-2019 09:09 AM
Originally Posted by endeavour32 (Post 4680418)
What is MER doing to get 650 hp out of a 525? That seems to be the most HP I've seen someone claim out of these engines.
I know Mark Rinda very well, but I can’t speak on his behalf for his technical expertise on engine building. He’s honest to a fault, so I know he’s not making claims he can’t back up. I have a lot of time riding and driving a 31’ Bullet with twin 825s that he built and they’re incredible. Give him a shout or look him up on FB.

jwurl 04-08-2019 07:29 PM
Mark at Mer built my 500 efi. Stroked to 540, afr heads, custom cam, and a modified 500 efi/525 intake with Tyler Crockett top mount throttle body kit. Best dyno pull was 693hp at 6000rpm. Jeff Wurl


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