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-   -   525 SC build questions (https://www.offshoreonly.com/forums/general-q/349739-525-sc-build-questions.html)

Griff 09-13-2017 01:19 AM

IMO, you'd be better off selling your 525SC complete and then look for a 502 that needs a rebuild.

You can't mill the heads more than .030 or you'll have issues with the intake manifold fitting.
If I remember correctly, every .005 taken off reduces chamber size by 1cc. You might be able to get about a 7.9 CR.

BBYSTWY 09-13-2017 05:49 AM

I agree overall that may be the best thing..however what I'm looking at is if I were to do that then I'm pretty much re rigging the boat with power steering, alt, etc which I don't want to do..I believe I can get a couple grand at least for my intercooled 174 setup so that means I'd have maybe another 2 grandish to be close to 700 with what I already have...truth be told I would expect in the next 4-5 years I'll be upgrading to a bigger boat so if I can do this build with what I have and have 4-5 years of trouble free 80+ mph boating(minus outdrive issues of course) then I'll be happy....I love the reliability of the 525 as I can run that thing damn near wide open for as long as I want with no issues and I don't want to lose that entirely....I know seems silly to think performance boating will be trouble free but I'd like to try with the motor at least lol!!

Thanks!!

Stewart

mike tkach 09-13-2017 08:03 AM

all the accessories from the 454 will bolt on to a 502.

ezstriper 09-13-2017 08:15 AM


Originally Posted by phragle (Post 4581941)
700 hp is going to eat bravos for breakfast.

Instead of milling heads, I would go with better pistons.. well I did go with better pistons lol....

You have a lot more blower than the 177. The combo Im putting together with a 731 roller cam, Al's heads, 8.5 compression and the 177 blower at 5 psi is supposed to come out over 600hp.

not in all cases, ran over 700hp with a std bravo(non XR) for 5 seasons with no failures, was in a 25 checkmate and were careful but ran mid 80's, on the 525, I agree with the sell it and just do a 502, you are gaining nothing from starting from it. If you insist on keeping it I would change pistons, as they are not available anymore and are odd balls, so if you ever need one its tuff...ask me how I know..

BBYSTWY 09-13-2017 09:04 AM

What kind of money do you think it would be worth with no accessories tho??? just the carb to oil pan with no ignition or accessories?? it has all msd ignition that I would like to keep and I don't have the stock stuff

525 sc with intercooler 520 hours

Also...would stock 502 pistons and rods etc. be adequate for my build with above blower etc??

thanks

Stewart

mike tkach 09-13-2017 09:11 AM

i don,t know what your sc525 is worth.some people have used the origional 502 pistons and added blowers but that is not the best way to go,if starting from scratch bying a piston designed for a boosted engine is the best way to go.

BBYSTWY 09-13-2017 09:14 AM

So I guess if I would have to buy pistons anyway...what would I be gaining besides a little bit of displacement?? not discounting your suggestion just trying to understand it fully

Stewart

F-2 Speedy 09-13-2017 09:15 AM

Isn't a 525 sc nothing more than a Gen 6 502 mag long block with a blower ??

Knot 4 Me 09-13-2017 09:21 AM

525SC is a 454, not a 502.

MILD THUNDER 09-13-2017 09:23 AM

525sc is a 454 with a 177 blower.


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