Fordtrucks

Lost oil pressure last day on the lake. Motor started to seize up so I shut it down quick. The thrust bearing on the rear main cap was toast which led to a few rods goin dry. A couple crank throws, rods and pistons are black from the heat so the machinist said we should not reuse this rotating assembly. What we have is a stock 97 MPI motor with Dana marine exhaust and a ProCharger. If the block is good were thinking a new forged 540, aluminum heads, bigger cam and ide really like to upgrade to the Holley HP EFI. looking for suggestions on parts and ideas. Also converting the tails to dry to tip.

Fordtrucks

What CR should we go with? Would it be better to drop it some and crank up the boost a bit?

If we go with heads like the AFR or Dart pro 1s, can I use my mpi EFI to end for now if need be, then convert to the Holley set up a bit later? I will be running 02 sensors so we could verify how it's running and have done changes made to the mefi 1 .. I kno this might not be ideal but I really want to build the long block right, but I have 6 months then we need to be back on the water and a guy only has so much money lol.

Fordtrucks

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Cole2534

iTrader: (1)

Fancy heads under the factory MPI intake setup seems like a waste. You could do a carb and intake for relatively cheap if retaining EFI isn't a must.

Totally agree with building a solid long block. On my N/A 509 the builder suggested the Callies Compstar rods and JE pistons. When we talked cranks he suggested a Callies there too, Compstar or Dragon Slayer.

hadleycat

I have the Holley Hp controller on my 1997 502 mpi. I am running a Procharger also at 7 lbs. I am still using my stock intake with bigger injectors.

Are you able to tune the MEFI1 yourself ? If so you may be OK. If you paying someone to tune it I would definitely invest that money into the Holley Hp controller. It can be used with your stock intake now and you can always upgrade the intake later.

Trying to tune your MEFI1 to a motor with that many mods could be time consuming.

I am sure others with more experience than me will chime in.

Young Performance

You can't tune the Mefi 1 to work in boost. It has no capabilities to tune in boost. You would need to go to a Mefi 3 or 4, the 4 being a much better choice (or something else like the Holley ecm) Your current setup is using Procharger's rising rate regulator to "tune" in boost. It raises the fuel pressure 3:1, 5;1 or 7;1, depending on the setup. To put it bluntly, it's a band aid.

You can certainly use your MPI intake with aftermarket alum heads. We do it quite often and have made well over 900 hp with it. (547 ci, Brodix heads, modified intake and rails to accept Siemens 65 lb injectors, M3 Procharger, etc.) Build a solid bottom end with a decent cam and heads, and you can make some pretty good power.
Eddie

Fordtrucks

Thanks guys! Eddie, that's what I was thinking.. Build the 540 up like I want and if I run out of money before I get the Holley stuff bought, just throw the stock EFI back on so I can get it on the water.. Then upgrade the intake, throttle body and computer with the Holley stuff another weekend..

If my 502 block is good, how big can we stuff in there? Is 540 about it?

What CR would you suggest? Keep it at 9-1 with 7 psi or less compression and more boost? Ide like a pretty good size cam..

Budman II

iTrader: (1)

Not sure if you have seen MT's thread:

http://www.offshoreonly.com/forums/g...ss-please.html

Point he is making is that you may find that you can make some really good power without stepping up to the 4.25 stroke crank. Maybe find a good stock GM steel 502 crank in the Swap Shop, buy some good rods, and put the money that you save into a really good set of heads and a good hyd roller cam and quality valvetrain components to make it live a long time. Just a thought.

Fordtrucks

Well, if I have to replace my pistons, rods and crank anyways, why not go bigger for about the same price?

SB

iTrader: (1)

'just throwing he stock EFI back on' cannot be done with out programming and other mods....on a well built 540. or 502 for that matter.

A smart old man once said - for every action there is a reaction.