looking for someone who has been through this. I want to go to 540's from my current hp 500 efi's. Can't decide whether to sell my hp 500's (170 hrs, efi) complete and start from scratch or sell the cranks, heads, maybe pistons and efi setup and use the 500 block and cmi exhaust, bolt ons etc. from the 500 and buy 540 crank rods pistons and new heads (afr). I am planning on not using the efi as my goal is 650 plus hp. Anyone done the math?

is supercharging your current motors not an option?..I dont have a lot of experince with the 500EFI's but i would think at
170ish hours you would be fine..

I made my 500EFI's 540's. If you want to ditch the EFI setup then just start from scratch.
I kept the EFI setups (with port work and monoblade TB) but I replaced the crank, rods, pistons, cam, heads, TB.....I should have just bought another block and kept the 500 long blocks intact.

But I did pull 630hp/700tq fully dressed on Precision Marine's dyno.

if you are going that route, sell your engines complete, way more $$ buy a pair of complete marine carb 540's you will far ahead $$ wise

I'm curious why to sell and buy 540's? Is it really beneficial? My bumped up 500's are only a few seasons old but if I decide to keep my current ride I am considering stroking the existing blocks. From a price point my builder can do it reasonably without the hassle of buying and selling. And I know how they were put together with what parts. Vallako did my induction and I out flow the Darts and am set up for bigger cubes. How much $ would be saved buying vs. Building???

On a 500HP carb engine, I would turn it into a 540ci.
On a 500EFI, I would sell them and start from scratch. There is just too much that needs to replaced or modified on the EFI to get the hp above 600-625.

Iwould keep what you have and install a set of prochargers..Ibet you will pick at leaste 10-15 mph..

Cool

The money that it takes to get the 500 EFI intakes to be able to supply enough air for a 540 set up can get pretty expensive. There are easier ways to do it.

There are a few buyers looking for complete HP 500 pairs. This may help decide which way to go, based on what u can get out of your motors.