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-   -   Building a pair of new 555's (https://www.offshoreonly.com/forums/do-yourself-boating-budget/343884-building-pair-new-555s.html)

SB 04-15-2017 10:25 AM

Good luck !

Got a wideband on those things ?

snapmorgan 04-15-2017 10:26 AM

20 percent overdriven

MILD THUNDER 04-15-2017 10:31 AM

Id take a close look over the igntiion system, plugs, etc. I had a bad plug on the dyno. Still made 760 on 7 cylinders. Replaced plug, 818hp. Had the marine exhaust on so no egts to tell me

snapmorgan 04-15-2017 11:56 AM

Unhooking it now. Made 850 at 7# boost. Will post sheet when I get home

MILD THUNDER 04-15-2017 12:08 PM


Originally Posted by snapmorgan (Post 4546522)
Unhooking it now. Made 850 at 7# boost. Will post sheet when I get home

Thats more like it. I would have thought around 900 with 9psi

sutphen 30 04-15-2017 05:06 PM


Originally Posted by snapmorgan (Post 4546522)
Unhooking it now. Made 850 at 7# boost. Will post sheet when I get home

what did you do to get the power up?good numbers,excellent job on the build

snapmorgan 04-15-2017 05:27 PM

1 Attachment(s)
Final pull. Spark arrestor on, full marine trim, lightning headers. I will tweek the AFR's if necessary once I get it in the boat.[ATTACH=CONFIG]566370[/ATTACH]

snapmorgan 04-15-2017 05:40 PM


Originally Posted by sutphen 30 (Post 4546554)
what did you do to get the power up?good numbers,excellent job on the build

Thanks, timing, jetting and valve lash. Found 70HP today It actually made a little better pull today with 35 deg timing and spark arrestor off, but not really real world.

As a side note. Made back to back pulls with and without water running through the chiller. I forgot to turn it on actually. Made over 30HP difference.
I have a Baker Engineering 7.5# mechanical pump on this engine. It is supposed to support 1200HP, but it won't keep up. 3 pounds of fuel pressure at 6000rpm with a -8 line in and out. Might have to ditch it for something else. I love the simplicity of it but ? Ideas?

MILD THUNDER 04-15-2017 06:22 PM

Nice build. What lifters you running ?

Always good when a build exceeds your expectations! :)

sutphen 30 04-15-2017 08:32 PM


Originally Posted by snapmorgan (Post 4546557)
Thanks, timing, jetting and valve lash. Found 70HP today It actually made a little better pull today with 35 deg timing and spark arrestor off, but not really real world.

As a side note. Made back to back pulls with and without water running through the chiller. I forgot to turn it on actually. Made over 30HP difference.
I have a Baker Engineering 7.5# mechanical pump on this engine. It is supposed to support 1200HP, but it won't keep up. 3 pounds of fuel pressure at 6000rpm with a -8 line in and out. Might have to ditch it for something else. I love the simplicity of it but ? Ideas?

can you change the spring to up the pressure to 10lbs?


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