500efi to 575sci conversion, what's needed?
 

Hey guys I'm debating trading/buying a pair of 575s for my 31 american offshore, I really wanna get into the triple digits, and the 500efi motors that I have aren't going to do it. What's all needed to put 575s in? And if anyone is interesting in trading let me know, engines have 170hrs on them and are spotless!

A Larger fuel tank!!

Less expensive to bump the 500 EFIs to 600+ HP.

The 500efi is a great starting point for a whipple. 700+ is very realistic. The 575's are flat tappet engines, and the blowers can be problematic at times.

+1 3.3 whipples and the ecm's can be remapped

Agree with the above. I have 575's and at the first rebuild of me owning them we made them roller motors and did a lot of work to make them "right"! Now they are 700hp :)

That said, you have a great platform to Whipple yours to 700. You get a whole new set of problems with the 575's.

It's not cheap, but I'd also look hard at the Whipple's.

I'd also consider going with larger cubes and staying NA if you don't want to deal with blowers. It's pretty easy to hit 700+ hp with a nice reliable set of 540's or 572's. If they were built with forged bottom ends and had flat top pistons, the CR can be dropped with thicker HG allowing you to add blowers to these engines and make a lot more power in the future if so desired.

+100 on whipping the 500s, and I am a 575sci owner. There is some real old, and sometimes oddball tech with the 575sci. You will not find direct replacement injectors, intakes, blowers, and thermo housings anywhere on the market. A 575sci can make some serious HP (mine are bumped quite a bit) but they are engines for a diy guy that doesn't mind tinkering and inventing solutions to engineered problems! The 575sci may also be the least fuel efficient injected engine merc made

Whipple the 500s, keep your stock parts, safely make 650hp and return the engines to stock before you sell the boat. The whipples on the used market pull big money. You will recoupe most of your money in the end, which never happens in the boating world :)

Eh....but blower whine drops panties!!

Just seems pricey to whipple the 500s at 10g per engine, I could sell the 500efi and buy some nice mild 600hp 540s that will run forever

Didn't for me, but then I'm twice as old as you..:drink:

Back to your original question............ there is nothing required to speak of to take out your 500s and drop in 575sci motors, check hatch clearance to see if they will fit. They are the same base platform (except 500s have roller cam already) same exhaust, etc...

That being said, I also have 575s warmed up to 700+Hp and they are going to be awesome. But to get them that way you are looking at 10K+ per motor to have someone do it for you, or 6K per motor doing it yourself (depending on how much machine work needed). You might as well spring for the whipples and be more MUCH more reliable with the same hp at the same price.

just my .02

hmmm

Well. Lets break it down then.

Your boat will always be worth more, a lot more, with blue merc engines in it. So dropping the stock power for carbed 540s will cost you down the road.

EFi with knock sensors, timing control is safer than the carbed 540s

No one said you have to buy the whippples new, search the market and find some take offs. They pop up at least 4 times a year on here.

Buying used 575sci can get expensive as well. Me personally I would not buy a used engine without having my guy tear them down before install. He seems to anlways find something not right.

The whipples will be money in the bank. Your boat will have stock blue mercs for resale, you can pull of the whipples and sell separately and recover most of the money spent on them.

Dustin at whipple has an extensive database of ECU tunes to make sure your whippled engine is running right, very valuable stuff without paying for a custom tune.

I purchased a single engine AO in February and dropped it off at Young Performance Marine. I would highly recommend you do the same if you want to get to 100mph economically with a nice package. He's good, honest and cares about what he's doing. When your boating season is over tow your boat to Young Performance Marine and tell him what you want to do and how much you're willing to spend to get there!

The 500s might be worth as much as used big blower motors. Just sell them.

Or go with centrifugal superchargers.

https://www.youtube.com/watch?v=_X7ldgGrZGA

I had a pair of n/a 540's 650ish HP -in my 31 Awesome.. put me in the 100MPH club real easy

sounded bad A$$

https://www.youtube.com/watch?v=_1IWae05ops

https://www.youtube.com/watch?v=SgPRiBGTZ1o

or just get whipples & be done with it! :picard1:

https://www.youtube.com/watch?v=e--DOPkoH2c

there's one in the classifieds 6K came off a 500 EFI looks clean 20 hrs

http://www.offshoreonly.com/classifi...o58711-en.html

How fast is the fountain going compared to me new boat, Phil's old boat

that's bad azz :ernaehrung004:

I was running high 90's :)

What speed are you at right now? What outdrives? You have to be close to 100mph as it sits I would think??

it will take at least 600hp a side & the right x dimension to break 100 in that hull (31AO or 31 Awesome) ask me how I know...lol been there , done that , got the t-shirt:lolhit:

I'm at 92-95 right now with box stock 30p bravos, 1.36 ratio, 12" stelling extension boxes set neutral. All at 5000rpm