Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   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)

tdbrickndirt 02-13-2019 08:37 PM
Most HP out of a 525
 
Just curious whats the most HP you have seen out of a 525 without using a supercharger or turbos? I went down to bare blocks and am almost done putting them back together with some goodies. Dyno runs will show if it was work it or not

MDG_Jason 02-13-2019 10:18 PM
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

Precision 02-13-2019 10:28 PM
Originally Posted by tdbrickndirt (Post 4672563)
Just curious whats the most HP you have seen out of a 525 without using a supercharger or turbos?
I stopped reading after this because you clearly don’t like to party.

tdbrickndirt 02-17-2019 07:04 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
Thanks for the reply. My motors went on the Dyno Thursday. They’re now 514ci. New heads, bigger valves, stiffer springs, better rocker arms etc. 657.2HP at 5750rpm and 641tq at 5000rpm. This was with a carb setup so when I put the efi intake back on the numbers will orobobe a little lower. Going to need to tune ecm like you did. Unfortunately I need new headers as fell so this rebuild is going to cost more than I was hoping lol

endeavour32 04-03-2019 07:51 PM
Did you ever re-dyno after the EFI was reinstalled?

rvtransport 04-04-2019 10:07 AM
The 525 intake runes out of air flow in the low 600hp range. Opening the mouth helps but its restrictive in other places. I did build mine last year made them into 540's opened intake and cnc heads stock cams and dyno 620 hp. But the motors gained a lot of torque. I gained 7 mph over stock 525's in a 42 Fountian.

Sydwayz 04-04-2019 10:19 AM
Pic from Mark Rinda at MER Performance in SC:

https://cimg7.ibsrv.net/gimg/www.off...8fd27f333.jpeg

rvtransport 04-04-2019 10:24 AM
https://cimg6.ibsrv.net/gimg/www.off...4c146d502a.jpg

Sydwayz 04-04-2019 10:32 AM
Originally Posted by rvtransport (Post 4680315)
I gotta say, I love seeing “blue power” in colors other than blue. I wish more folks would have opted for that upgrade. I always wanted to build a pearl white 37AT with one red motor and one blue one.

F-2 Speedy 04-04-2019 10:38 AM
a 525 is a 502.............lets stay in line folks.....:poopoo:

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


All times are GMT -5. The time now is 02:30 PM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.