500 efi long block replacement
 

I have a 500 EFI that threw a rod and ended up cracking the block.

I want to get a new long block and bolt all of my 500 EFI
componnants on to it. I understand that I may need to change the cam.
If you have the cam specs that would be great.
Max performance is NOT my main concern as I am running this in a 20.5 Cougar sport skier.
I purchased this motor from an offshore only member.
This engine had been built by "Jasper Engines" and was a mess inside.

I am looking for a 502 longblock which one is correct?

Thanks

You could use a ZZ502 short block and rebuild or buy heads set up for marine use. A cam change would be needed also.

Is your existing cam damaged? Why not re-use it?

we have not removed the cam yet
How can I be sure the cam that is in it is the correct cam?

after doing some research it looks like the
GM 502 HO long block has all of the correct internals?

Here are the specs for a 500efi cam. It was a Crane custom grind made for the Merc 500efi. Not sure if Crane makes them anymore.
500 EFi cam
292*/298* Adv
230*/236* @ .050
.598"/.610" @ valve
114* LSA
109* ICL
119* ECL

The Crane 168731 is very close in specs to the 500efi cam and can be used as a replacement
http://www.summitracing.com/parts/crn-168731

It will work except for cam and heads need to be worked, ie, inconel ex valves, springs matched to cam you use and loosen up guide clearence a little. That would do you.

would I be able to use my existing valves and rockers?

thanks for your help

I did a zz502 short block last year. You don't really need the long block if you want to use your existing heads. I used my cam and had my existing heads reworked. I have put about 30 hours on it since we did the change and everything worked out great. I think I paid $4,995 from jegs with free freight. I sold the cam that came in the engine on ebay. If you have any questions PM me and I will give you my phone number.

This is the one I bought.

http://www.jegs.com/i/Chevrolet+Perf...68782/10002/-1

I would put new valves, springs, retainers etc. Your engine blew and when rebuilding replace these parts. You have the engine apart- send the heads out too.

Wannabe

Hello again Guys and thanks for your input.
I have puchased a GM Marine 502 HO longblock
I want to back to or as close as possible to the original 500 EFI specs
Can someone reccomend who I should have work on my Heads?
I live in Washington state and it would be great if I was able to do it local
any other advice in making the motor dependable would be appreciated.
Thanks