502 to 540's
 

I've got a pair of 1995 502 stock motors with just shy of 700 hours on them. When I have them refreshed I want to make more power. What is a good ball park figure to getting them to 540's and keeping them naturally aspirated?

If they are the MPI motors you'll have to ditch all that and go carbs.....just no way to get enough air through the 502 plenum (I had the same problem when turning my 500EFI's into 540's)

Compared to a re-fresh you'll also need: Machine work will be more, crank/rods/pistons/cam. If your boring it then you'll need head "work" at minimum if not new heads. Then carb/intake/ignition if replacing an MPI system.

I would look at putting good heads on 502s, ahead of stock heads on top of 540s.

Seems like easier way to get more power is good heads and a cam change, reflash, HP500 intake or modify existing, better exhaust.

2K for rotating assy
2K for cam, lifters, rockers, springs, pushrods
1K machine work
+ whatever amount you want to spend on heads
Add anouther 2K for oil cooler, lines,fluids, gaskets, accessories and dyno.

Should be able to do it for about 10K each

While I think your close on parts, the way I read his post he's paying someone to do the work.......Labor is going to be another 2K

Plus you might as well upgrade the exhaust or else you'll be all clogged up there so add $2000 for that and then you need to re-prop to get all that power to the water so add another $1000.

Hope your drive is in good condition.:eekdrop:

Wow , nothing like discouraging a brother . Who sells the best balanced 540 rotating assembly for the best price . My 500 H.P. wants to be a 540 when it grows up !! Can you say RM Builder !! Don't mean to hijack . :evilb:

It is a very expensive way to gain 38ci so about 38hp. Other ways to do it for less money, less hassle.

You forgot less dependable . 38 CI and 150 hp gain is what i'm lookin at and will sell off all the stock HP parts .

for that kind of gain you will need a head change along with the 540 rotator.

I say put a blower on it.

To gain 150HP, you'll need a rotating assembly, even if you go with Scat stuff your looking at 2k, just in crank, rods, pistons, rings with the ARP bolt upgrade.

You'll need to get the machine work done, a new internally balanced harmonic damper and flywheel, probably another 700 or so.

With block machine work, balancing, etc, I'd say you'd have 3500-4000 just in the shortblock.

Youll need a GOOD set of heads. CP sells Dart Pro 1 marine roller spring heads for about 2500 bucks a pair.

A new Cam and say some morel roller lifters, timing chain, possibly pushrods, around 1000 bucks.....

Stock HP 500 carb wont cut it, so figure another 1000 bucks for a new dominator carb.....

Misc gaskets, and parts, another 500.00......

My guess is you'll be somewhere in the 10,000 dollar range to squeeze 700-725HP out of your HP500, N/A.

Or, if the engine is healthy, you can pick up something like this, and bolt some carbs on, and make the power you're seeking for around 3500 bucks....

http://www.offshoreonly.com/classifi...o43863-en.html

Point well taken and will be considered . My HP is in great shape but before i did something like you suggest i would refresh and def go with AFR heads and ARP studs .