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-   -   800 SC specs and questions (https://www.offshoreonly.com/forums/do-yourself-boating-budget/376891-800-sc-specs-questions.html)

WR-1 08-27-2022 09:01 AM

800 SC specs and questions
 
Looking to build my hp 500 around the 800sc platform and would like some advice on specs and est hp.. I'm using my hp 500 short block after refeshing... I'm sure the 800 probally came with dish pistons but I'd like to use my current pistons and run lower boost.. I have AFR 305 cnc heads I'm using, 420 mega blower with superchiller,quick fuel 750s, going with a hydraulic roller cam set up similar to a 741 but with a 2/3-4/7 swap.. did the 800sc have mechanical fuel pumps only or did they have electric in addition? I'm using a K/E mechanical now, I believe it's a 140 gph.. would that support my carbs safely with a good bypass regulator? Thanks for any advice or suggestions 😊

bencini231 08-27-2022 01:37 PM


Originally Posted by WR-1 (Post 4842972)
Looking to build my hp 500 around the 800sc platform and would like some advice on specs and est hp.. I'm using my hp 500 short block after refeshing... I'm sure the 800 probally came with dish pistons but I'd like to use my current pistons and run lower boost.. I have AFR 305 cnc heads I'm using, 420 mega blower with superchiller,quick fuel 750s, going with a hydraulic roller cam set up similar to a 741 but with a 2/3-4/7 swap.. did the 800sc have mechanical fuel pumps only or did they have electric in addition? I'm using a K/E mechanical now, I believe it's a 140 gph.. would that support my carbs safely with a good bypass regulator? Thanks for any advice or suggestions 😊

Give Eddie Young a call @ Young Performance Marine in Mt Juliet, TN. I'm pretty sure he just finished up a pair of 800 SC's earlier this year. He can answer any question you have for sure.

WR-1 08-30-2022 10:23 AM

Thanks for the advice.. no doubt Eddie could answer my questions, I was just looking for other guys thoughts and experiences as well..

snapmorgan 08-30-2022 02:12 PM

The 800sc is 572ci, dished pistons and uses a mechanical fuel pump. Are you planning on stroking your 502?

snapmorgan 08-30-2022 02:14 PM

I built a pretty healthy 420 blower motor a few years ago. 555ci, Brodix 365 heads, crane 651 cam. Made 900+hp
I torched a piston in it first trip out due to fuel delivery problems with the Baker mechanical pump. I wasted alot of time and money with pumps, regulators and rigging trying to make it work and keep it simple. My advice would be to put a good electric pump on it and be done. That is what I ended up doing.

Did you still have my phone #. Give me a call if you want

WR-1 08-31-2022 06:52 PM

What's up buddy? I didn't realize the 800sc was 572ci.. I assumed it was a 502 based platform.. but to answer your question, no I hadn't planned on stroking it. Hoping to use my current short block and rotating assy.. thanks for the heads up on the fuel system.. that's what I'll do then, probably go with an aeromotive system and a bypass regulator..yes I still have your number, this is going to be an ongoing build over a year or maybe 2 so I'm sure I'll hit you up in the future with more questions.. thanks a lot.. hope things are well my friend

snapmorgan 09-01-2022 09:56 AM

I have used both the Aeromotive and Weldon pumps on different projects over the years. I personally believe the Weldon is a better pump for the same money. Call me any time

TomFTM 09-05-2022 08:46 AM

The merc 8oo sc was built on a tall deck block. 4.5 bore 4.5 stroke .

Unlimited jd 09-05-2022 09:34 AM

Besides the 420 blower, none of your combination will resemble the 800sc.
the 800 was a dished piston low compression iron headed 572. Very basic engine, I believe it even had a flat tappet hydraulic cam.

SB 09-05-2022 10:19 AM

Found this here:

Originally Posted by MILD THUNDER (Post 4498816)
The 800sc (not 800sci), 600sc (not 600sci), and 575sci, used the same cam. Which was a 240/240 @ .050 .559/.559 lift 110 LSA hydraulic FLAT tappet cam.

525SC, used the same 228/236 at .050 530/551 lift 114 LSA flat tappet cam, that was used in the 400hp, 420hp, and 425hp mercruiser 454ci engines.

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