500efi Heads
 

OK - I KNOW THIS HAD TO BE DISCUSSED BEFORE, BUT...

I HAVE YEAR 2000 500EFI's approaching 250hrs.

This winter I plan on doing the recommended head gaskets, valve springs, etc...

My question is:

- Instead of having my stock heads reworked, valve springs, valve guides, etc... Are there aftermarket heads that are ready to bolt on and be able to see any signifigant gains in horespower without having to burn higher octane or do anything else serious to the engines. If so, what recommendations would you make. Thanks in advance. Ted

You would have to do an ECM reprogram if do hp mods. Best bet would be to call a reputable builder with a proven package/combo that already has a dialed in package and has a dyno proven ecm recalibration already done.

Totally agree...There are plenty of great head packages out there, but they need to synch with your package after they get bolted on. Carder

Great! - Where would this person be???

Great! - Where would I find these head packages?

I used Tyler Crockett. You can email him @ his website;;;
crockettmarineengines.com or call him (810) 324.2720
He is helpful, and doesn't treat non-gear heads, (like me) like they are idiots. Carder

tyler crockett or mark at precision

Are you changing lifters? I ask because when I did my spring, we found a bad lifter. Changed them all. 240 hours.

I was just debating this with a friend the other night.
It comes down to $$ as usual. Sure you can buy a better set of better flowing aluminum heads.
But, unless you change the cam along with them, are you going to gain enough to make the $$ worth it?
He has decided to have his GM heads rebuilt/valve job with new exhaust valves, springs,... and some bowl porting.

Thats why I started this thread. Doing my research now so I have my ducks in a row for the winter projects. For me, dependability is important. I typically put around 50hrs a year on my boat - so whatever I do I am going to expect it to last another 5 years. Just like everyone else - if I spend thousands of dollars on preventive maintenance - it would be nice to get a little more punch in the process.
Also, I will not be replacing the cam unless I find its in trouble when I open it up.


CANADA JEFF

I will probably replace the lifters as well.

You can buy Edelbrock aluminum heads like the ones on the Merc 525 for about $1600 per set including the valves.
I don't know how much more power you'd make without a cam change though...

The stock heads on an HP are limiting in stock form. Either open them up or just replace them with Aluminum heads like Dart for example.

I pndered the same question when I put the Whipple on this spring. Was close to the same cost to have the heads rebuilt (seals, guides, seats, etc) that is was to just replace with new Aluminum heads that flow better and had all new valves and springs installed already!

Do the numbers.....and resurch the results.

I agree that the Dart Aluminum heads will flow better.
But they are like $2500+ per set fully assembled. Surely you can have a set of 250 hour old GM iron heads rebuilt/valve job with some porting for a lot less than that. I'm thinking 1/2 including new exhaust valves, springs, and...