HP500efi mods

[Bob280Silencer]

Has anyone tried using 1.8:1 rockers,advancing the cam,changed fuel pressure;you know,all the old car racing stuff?How about Electromotive ing. systems?I would like to step-up my HP a little and was wondering if some of the car tricks would work.It's tough to get anything out of Mercury Racing other than stock specs.I plan on Pro-1 heads this winter and any other changes that might help. Thanks,Bob

yes I think every thing has been tried ,do a search on here on 500 mods,,ect,
I do it every day somedays twice


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need to do alot other than throw on a set of heads ,what size are you going to run ,why?? are you planing for later mods when installing heads ect.

[Bob280Silencer]

I will probably run the 325cc runner Pro 1 Darts and extrude hone the intake.Probably deck the block to get the compression up to 9;1.Haven't given any thought about changing the cam especially if 1.8:1 rockers will hold up.Thanks for getting back to me.Gotta go figure out how to search for HP mods. Bob

Bob just go to search on the bottom of a thread and type in your search it will find tons on hop ups heads,cams,ect
The factory cam is junk as are springs ect the bottom end is o.k

if your never going to run a blower and want 600 + power
use a crane 741 hyd. roller cam and the heads and 9.25 to 1 it will fly

[Bob280Silencer]

Bobby,I'm trying to stay away from blowers.(notice i said TRYING) That Crane 741-is that 168741 or 139741? Why do you like it over the stock one(whatever that is).Don't like the springs either?I thought HP were suppose to be full of good stuff!?

[Vinny P]

Bobby,
If he goes the route you suggest, what about re-mapping the ECU?

[Bob280Silencer]

checkmate454mag,ECM has been re-mapped & works in the winter but still runs fat in the summer.(no air)I've road raced cars for 25+ years & it bugs me to pull a plug & it's black ,plus that transom thing(black too).Down here we boat year round(no winter)so it's hard to get the ECM to work correctly all the time. I'm working on a way to slightly adjust the injector timing through the coolant temp. sensor.Let you know if it works.Bob

yES WE CAN DO THE ECU FOR YOU OR AZ SPEED CAN ,
The springs go away at 200 hrs of normal use or much sooner
they are truly junk the stock cam is for emmissions and idle ect. the 741 is a much much better cam the one thats a 731 is also
a very good choice ,I have 3 cams custom ground that do better but these are cheap and work great the motor needs compression if you go to aluim heads (heat) to keep the power up ,the pistons are J&E'S and are fine ,,also the rockers will go away at 200 or so hrs of running (in most cases )

By the way, the Crane 168741 is available in a marine version with almost the same spec's - part number is 16HR00004. Lobe center is 114 instead of 112 which may or may not be an issue.