496 Mag HO to Merc 525 EFI
 

I would like to pull my 496 Mag HO and drop in a 525. Anybody done this switch? Both engines have switchable exhaust, will the factory headers on the 525 cause the exhaust cutouts through the transom to be different? Throttle linkage the same? The 525 is in a boat with smartcraft gauges, will the gauges work hooked up to the 496?

Geez must not be possible

look up member "Sweet Addiction" here, he just did this last summer.

Why don't you just upgrade the cam in the 496 and have 525 hp...? A lot less than buying a complete 525...

They were an option from Merc and Volvo I beieve, and built by Innovation Marine in FL..

Just my $.02

It will work. more than likely, You will need new tail pipes off of the headers. The computer will run the smartcraft or the analog guages. Let me know if you need some help, I know someone in your area that can handle the swap.

A 525 is a much stouter motor than a 496. It has all forged internals, and aluminum heads. Also, being a Mercury Racing motor, it is rated at 525 hp at the prop which equals about 555 hp at the crank. The 496HO motor is heavier, and makes 425 hp at the crank. This is a bolt in swap. 525 motors are awsome. You will never regret it.

Chris

The 525HP cam is the 496 HP3 (525 HP) cam and it is a pain in the ass - you need special push rods and good rockers and better heads. The things that limit HP on the 496 is the intake, and heads - they dont breath well. Then, you have the cut the rocker nuts down for valve cover clearance too. Depending on distance, you should have 12-18 in of rubber exhaust so you can work with the differences between the 496/525 header issues.

Get the 525 - the biggest issue is the wiring harness on the 525 it is different than the 496 harness.

That is the real issue you have... for the right people, it isnt even really a big deal..

I have converted from 502's to 496's in the past and with the difference in the angle will burn a hole through the exhaust very quickly and down here in Salt, that is something you don't want to see happen.

Keith,

Would be interested to know what your 496 set up is and what you are using for rocker arms.

im sure ray from raylar will chime in soon... he knows his stuff!

Yes he does.

Raylar has some really good mods for the 496.

Chris