HP500EFI Mods.
 

I have read some posts on this site regarding this issue. I know that Whipple and Procharger offer mods for this motor with substantial gains in HP.

But this is my question... Has anyone successfully performed mods to this motor (maybe to see 6-700 hp) and retained a naturally aspirated motor.

If you have, who reprogrammed your ECM and what other mods did you perform or what builder did you use.

Was it worth F' kn with at all ?

Thanks for the replies.

Hot Water...Started to do that very thing last year. By the time we figured out all the changes, heads, cam, increasing stroke to a 540, and reprogramming ecu, it was easier just to by a whipple system for that motor. Put almost 100 hrs on it this summer...no problems great horsepower. Arizona Speed and Marine can reporgram your ecu for what ever. I think Dustin Whipple can also.

Just went through this....
 

I've looked into EVERY concievable combination to keep my hp500efi's NA and make 600-700hp. Tyler Crocket has a pakage that will net you around 610-625hp. It includes Brodix Alum. heads (cnc and ported), cam change, reprogram the ecu, fuel pump, and if I remember correctly larger injectors. I believe it runs around $4500-$5000 for the parts, not including labor if needed. I also looked at the Whipples! Nice package, lots of hp and torque but around $7000 for the kit.

I think I'm going to run The Blower Shops new low profile (should fit under the hatch) 250 blwer kit with a single 4500 Holley carb. I'll need to up grade my ignition by adding a Crane Fireball Ignition, as well as, a back up fuel pump. I'm looking at around $4000-$4500 in parts (I'll do the install myself). It should make 650-700hp at 4-5 lbs. of boost according to Marv at The Blower Shop. The motor should have no issues with driveablity or reliability. Seems like the most bang for the buck (not to mention how cool the polished blowers look on those motors).

Goodluck!

Yes, the efi systems are coming off for the time being. When I go to sell the boat (or motors) I'll put them back on and sell the blowers/carbs seperately.

That is of course unless someone would be interested in buying 2 complete efi's (hp500) units with Arizona Speed and Marine flame arrstors???

Hey Jeff,

I would be willing to include the cool system and pump if the money is right. Make me an offer on the systems! Including the above mentioned components.

Jon-

I just installed the ASM super tune kit's in my 33' Daytona. I have not run the boat yet. I will post results after I run it.

bad kittie please post results of asm super tune kit , i put this kit on my 1998 502 efi (415hp)