454 MAG w/Whipple EFI ?

[KC]

I just picked up a 454 MAG MPI 385hp with 20 hours on it for a great price, a good bulletproof motor, it needs a fuel system including the intake. So I am calling Whipple today to see if their 7.4 MPI 310hp system will sit ontop of the 385hp MAG, I think it will!
Has anyone do this?
KC

[502procharger]

good to hear you found a motor. where did you end up finding one?

[THOR]

THOR,
KC, you sneaky bastard. That is the motor I have and it runs great. I too would love to see what a whipple or ProCharger would do. Have you checked both? A friend of mine has the 7.4 and put a PC on it for a gain from 64-74 mph. Sweet

[KC]

I have been on the phone with Whipple all day....
On the Whipple website is a photo of the 7.4 MPI 310hp kit that they sell, or used to sell. Unfortunatly the 310hp motor components are not strong enought for the extra power so Wipple suggests replacing the pistons and rods. That equates to pulling the motor and fitting new pistons, a 2 bolt mains motor at that.
Whipple also offers a kit for a 454/502 Mag MPI, it bolts onto the side of the motor and uses the Mercruiser Injectors with a remapped ECU.
It sounds like Whipple is phasing out the side mount kit, in favor of the top mounted kit as shown in the 7.4 MPI photos. The kit comes with an intake manifold, intercooler, 2000cfm throttle body, injectors, re-map of your MEFI 3 ECU, all small goodies including pulleys and belts - and a day of calibrations on the ECU on their local lake.
This makes for a very clean implementation of 615hp on my recently acquired 454 Mag, over 700hp on a 502 Mag.
I snagged the motor off of EBay, a complete long block with 20 hours on it less the intake and fuel system, I hope it is as clean as the guy says. This guy built a 540 motor and placed the MPI from the 454 onto the 540 with $1400 worth of ECU mapping.
My game plan is to unbolt my accessories from my 310hp motor, take the boat to my service shop so they can crane out/in the two motors. Then bolt the Whipple kit and all of my accessories onto the new motor. Finally tow the boat from Havasu to Whipple in Fresno so that they can do the calibrations on the ECU. I hope to accomplish all of that over the Christmas Holiday shut down at work.
Currently I have the Stainless Marine headers and risers to help this monster exhail.
The next questions are... do I need a Bravo I 26p or 28p.... gear ratios?
Nice thing is I have lots of time for research.
Too bad Whipple does not offer zero percent down and zero percent interest!
KC

[502procharger]

kc, you will need a 28p bravo 1 prop. it is rally a 26.5 when comp. to other props. i have around 600hp now and run that prop. it is grat. i may even be selling it due to the fact that my new 540 procharged motor should run 800hp-850hp. i will let you know if i put it up for sale. good luck with the new motor.

[KC]

502procharge....
Thanks, I'll be calling the propeller company in the AM to get their read on the prop and the gearing.... sounds like I need to have the prop stepped up before whipple tunes the ecu.
This is fun! KC

[502procharger]

i guess i need to look at the screan when i type, i look like a retard with all of the spelling mistakes.

[THOR]

KC,
My buddy that did the same thing is running a 28P on his 22' boat. But, that is a smaller rig than yours. I would run an 26P or maybe a 27P mach if you can find one. I doubt you would want to push that motor to its limits for an extended period of time.

[KC]

Thanks guys!
Yes, I would prefer acceleration over top speed, so a 26P might be the ticket for the Whipple.
Still working out ideas on this motor, the Whipple is big bucks and I just don't want to dive into the deep end so fast. Good and bad, is that my new motor is basically a long block, so no fuel system but it does have the MPI cam. If I can find an MPI system then I have a sweet low budget motor, but if the MPI is spendy then I might as well apply the funds towards the Whipple.... I have plenty of time on my side.
Thanks for everyones input, KC

[Mach1Shorty]

KC - I have a 454mag efi also. Been kicking around the same top mount whipple idea. But one step farther -- I was thinking of putting 8.0:1 flat top pistons in, the 500efi cam in, and a little head work. Then bolt on the top mount whipple and get the ecu calibrated. I'm thinking it'll make around 650-675hp and still idle nice. And at 8:1 I have the option of bumping up the boost on occassions. :D
If anybody's done something close to that, I'd like to hear about the results.

[KC]

I'm leaving the pistons as is, though I might drop the compression by softening the bowls in the heads.... easier than dismantling the block.
Still waiting for my motor to arive, then I will be evaluating the stock heads vs. aluminum heads.
I wish I had specs for these Mercruiser cams, it would be interesting to see the difference between the following motors:
- 7.1 MPI 310hp
- 454 Mag MPI 385hp
- 502 Mag MPI 410hp
- HP500 EFI
Spoken to Whipple a few times now, Dustin has been great help. I'm still working on the budget for this project, so far things are looking good.
- motor
- gasket kit
- roller rockers (a nice to have)
- Whipple system
- new prop
- engine swap
Having fun! KC

[Mach1Shorty]

Here's what I've gathered so far...
The 454mag mpi & 502 mpi both use the same cam:
Merc Part# 431-850478
224/224 .483/.483 115.5
The old 525sc (454 w/174 blower) uses:
Crane #132561
228/236 .530/.551 114
The 500 efi uses:
Crane #169621
230/236 .598/.610 114
The 525sc & 500efi cams are similiar, just more lift. So since the whipple is bigger than the 174 that the 525sc uses I think the 500efi cam will work pretty good. Have to talk to the whipple people, but I'd bet the 500efi whipple kit would work and the fuel mapping might not be too far off. Just have to have it recalibrated. Dustin may have a better cam recommendation, have to check.

[KC]

Thanks for the detailed cam information...
My 454 Mag arrives this Friday.... Ordering head gaskets today. The motor will be bone stock except for the Whipple EFI System, though it will be running AmsOil.
Talked to everyone about a prop, so far the 26P is getting the most votes.
The next two months will be an adventure!
KC

[502procharger]

keep in mind a 26 bravo 1 is just 1/2 deg more pitch than any other prop manufacturers 24p. for some reason bravo 1 4 blades are 1 1/2 pitch lower than there stated pitch numbers. so i run a 28 bravo 1 and it is actualy just a little more pitch than 26. ask anyone who knows props. good luck with the new setup.

[KC]

502procharger....
Your the second person to tell me that... The math says one thing but the performance of the prop tells another story...
First I'm going to test with a 28P, if I can hit the rev limiter then I'm leaving it on. The guy that I am buying my motor from had a 26P Bravo One on his boat, with the bone stock 385hp 454 Mag - he said it was slow out of the hole but it would hit the rev limiter. So tacking on an additional 180hp with the Whipple system the motor should turn the 28P Bravo One with no problem.
Let me know if you decide to unload yours.... I'll be needing one in the first week of October.
KC

[KC]

oops... I mean an additional 220hp with the Whipple System. KC

[502procharger]

kc,
i run about the same hp as you with my carbed/procharged 502. i spin the 28 bravo 1 all day long at 5100-5200 on my 25'v bottom switzer. do not buy a prop until you try every one you can get a hold of. every boat responds diff. to every diff pitch, rake, and cup. my good buddy ownes a prop shop and that is all he does is sell, fixes, blueprints ss props of all brands. i spend a lot of time at his shop just learning about what diff. manufactures do diff. with there props and what the effect is on your boat. what it reaaly comes down to after you add hp is what works, not what others tell you should work fine. good luck. let me know if you have any questions.

[Mach1Shorty]

KC,
Got off the phone w/whipple today. Sounds like you've got the best plan. The top mount kit they have for the stock 454mag is supposed to hit 615, maybe a little more with headers. The old kit was 590hp which was quite a bit less than the 650 I was shooting for. That's why I was thinking cam change. But if I can end up around 625hp with the headers and no cam or piston mods, I'm in spittin' distance. I think I'll take the easy way out. Plus the programming is done, so I can just mail in my ECU and won't have to tow it out west (although I was kinda lookin forward to that).
We whittled the mods down to adding the inconel exhaust valves, new valve springs, a felpro head gasket, and headers. My winter project just turned into a few weekends of work. Now what I am gonna do all winter! :rolleyes:

[KC]

Mach....
My system should be here next week, it will take me a few weeks to build my motor and deliver the boat to them for the calibration - once that is done you won't need to deliver your boat to Whipple - but you can still come out to the river!
I going to drop in roller rocker arms and I allready have the Stainless Marine Header, with that the motor might be something close to 650.
Can not wait! It certainly looks clean! KC

[KC]

My budget got blown out of the water this weekend, so no Whiple System at this time. Bummer, maybe another time. KC

[502procharger]

kc, what happend? you were so close. oh well, next season maybe. how was the chortblock you got? i hope nothing to bad happened to you(and your budget.

[KC]

502procharger...
Yes, I was very close.... now I'm on the lower budget path, spread over many more months - no big deal.
I drug home 454 Mag tonight, very pretty long block. Now what to do with it? KC

[Livin Large 27Hallett]

Sounds like you might be spending some money real soon KC. I can see it know, KC is thinking " More horsepower, Hmmm, all I have to do is raise the rents a little"