I would agree 700HP is about all you would want to push the internals of basically stock GM 502 (HP500EFI).

If you want more than 700HP reliably, then it is better to build a tall deck monster 572+cube with high $$ internals. I would guesstimate 25K+ from a professional with a warranty.

My suggestion of using the HP500EFI as a base is so you don't have 2 engines to try and sell. So what is a used HP500EFI worth?

The way I looked at it was to build the best engine I could afford today. When I get board with it, just add a 3# boost Procharger to it (back off the timing)for another 2-300hp.

Hey Faster,
Another 2-300hp?
You are already at 800HP; What about the out-drive?
Jcap has broken 2 or 3 Bravo XR drives with 700HP.
Zuper broke 2 Imcos and then changed to a Speed master.

Company called MAX MACHINE WORX in Havasu is modifying XR's for 1200hp power plants with great success.
http://maxmachineworx.com/

Hey Huntington,
What type of EFI unit will be used on that 600 you're having built? AZ Speed like the Merc. 525?
What size short block?
I have seen the the AZ Speed used on 600HP 540cube engines.
I did acquire an AZ Speed unit from a Volvo Penta engine that will be used at some point to build a 500. Just need some time and $$...

1200HP
Holy Crap!

Pat, AZ speed is the ECM used... the block is GM motorsports 502... looking into going to a tall deck block like dart or something but it doesn't seem like the extra cost is going to be worth it unless this was going to be a big cubic inch monster one day and I don't see a need for it. Like its been said 800 gets you in the 90's and my motor blown will make around 900 so I can still hit triple digits without the exotic block and money that that would cost

Hey Huntington,
Will your engine have aluminum heads and cosed cooling?
Sounds like your having a hopped up version of Mercs 525 built for 5-7K less.
Good Luck!
Is there a thread for your new boat yet?
Maybe we should change from Eddies...

Threads kinda going in the NYC thread I'll post a responce there

I agree,Max has the best upgrades,just don't forget your still getting stock xr upper and lower gears in there drive too and at 800 plus hp and ft lbs tq these parts can and will fail. I recently chewed up a set of lower xr gears in one of their upgraded drives. I'm not *****ing though,they lasted just over 60 hours but I have over 900 ft lbs of tq,Smitty