Engine upgrade advice - 500HP / 525EFI
 

Im in plans of upgrade my engine from Merc 496 Mag HO to 502 cui.

My boat is a Chris Craft 260 Stinger -87.
Without anything the weight is 1795 kg/3950lb.

I have a Bravo X upper with XR lower drive mounted on a extentionbox with IMCO hydraulic steering.
So I hope my setup beside the engine is good to go with more power.
I read that the Bravo X/XR drives can handle up to 600hp? can it handle more or is it maximum power?
Im aware that hours and condition of the drive is a huge factor for this.

Im thinking of the Merc Racing engines.
I have looked at two engines:

The first engine is a Mercury Racing CARB HP500 with DART heads and block. Rebuilt and complete engine, just put it in the boat and go.

The second engine is a Mercury Racing 525 EFI. This engine isnt complete.
Coupler, oilcooler, exhaust, glycol reservoir is missing. One guy started to build the engine from the beginning and stoped at the finish line.

The price for the Merc carb HP500 is 88k SEK.
The price for the Merc 525 EFI is 100k SEK.
(Im from Sweden).

What do you guys think.
How is the engine upgrade possible with those engines, like if I want to put a whipple supercharger on it?

Pros and cons with those engines, original and upgraded with supercharger.

Im more for the HP500 in this case because it is a complete engine.

My second question -
How is the engine mounts for the HP500 and the 525efi? Is it exactly like the 496 or do I have to rebuild the engine mounts?

Thanks!

I think the 496 is a bit wider . Now where the actual mounts are could be the same.

If you're running in salt water Id build the Merc 525 with the closed cooling, what are those prices in US $$

The mounting points on all of those engines are the same.
A Bravo1 drive is unhappy over 450hp.
A Bravo X is unhappy at 525hp.
A Bravo XR is unhappy over 600hp.
These are "guidelines", but you should pay heed to those limits. Upgrades are available to exyend those limits..
An extension box on your hull will likely require a shorty lower unit or raising the engine/box to change your drive height in order to get best results.
You can upgrade your 496 to the 500hp level inexpensively. In fact, you can go to 600hp on your 496 for under 7,000 usd (with new heads, new pistons, etc for basically a fresh new engine).
My concern is that your 260 Stinger is not a particularly fast hull design. Deep vee, no notch or pad, no steps. Its age also suggests the possibility of soft stringers which will allow hull deflection (counterproductive to speed).
I have to ask - what is your goal regarding speeds?

M

$10,000 and $11,4000

$10k for the hp500.
$11.5k for the 525efi.

The HP500 is complete and rebuild.
DART block and DART heads. So I think there is more than 500hp in this engine?!

The 525efi has missing parts for like $5k parts.
Like oilcooler, glycol reservoir, hoses, exhaust. Dont know the condition of the engine..


Good! Then I dont have to remake the engine mounts.

I have a extentionbox already and did have the Sportmaster lower but the hull didnt like it. Not whit my engine. Changed the lower to a XR to get the prop shaft down to 3,7” below bottom.

I dont want to upgrade my 496, I just have heard bad things happen with overload of the 496 engine...
So I think the 502 block is what I want.
Just so I can get a little bit more speed and power and maybe the oportunity to upgrade the engine later or put it in another boat.

I think my bravo x upper is a diesel bravo x so dont know if it can handle more power

If you are in Sweden its worth it to buy an IMCO SCX. Have it shipped and forget about it. If you have an XR and need parts I cant imagine the prices and lead times are enjoyable, in the long run it will be cheaper to buy the SCX up front and have the reliability.

The IMCO SCX has much better Quality/handles more power than the XR?

yes, about 15K more power and 2K for the helmet.......:ernaehrung004:...good advice if you can swing it