502 MPI upgrade results

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01-20-2012 | 12:51 PM

#41

HaxbySpeed

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From: Vancouver BC

Quote:

Originally Posted by snapmorgan

Haxby, I believe that I have the white painted, ported and extrude honed manifold that came off this engine. I was planning on putting it on my 540 along with a larger throttle body. I think the stock intake is killing my top end as it will only turn about 5100rpm no matter what prop i put on it. Do you think this is going to be enough intake, or should I scrap it and put on something else? I have about 575hp now and looking for about 625. Also plan on dynoing before and after the intake swap to see exactly what happens.

Engine is 540CI, Edelbrock rect port marine heads, Madara custom cam, 9.2-1 compression, Imco powerflow exhaust.

I am really looking for a few more rpm than anything else. Maybe 5600-5800.
Thanks

The manifold I gave you should get you another 20-30hp but it's still leaving a lot on the table. If you look at the original dyno sheet on this thing you can see how much it picked up with the Vic Jr. On your 540 it would be even more. Without the flame arrestor this combo made just under 550hp. That's running both water pumps, alternator, and power steering pump, with wet exhaust. A better intake alone is probably worth 50-60hp on your application.

02-02-2012 | 02:28 PM

#42

hickle44

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i know this is an older thread but i have a 2000 454 mag with @240 hours on it i'm looking for more power.does anybody know if some of these mods. would pertain to my motor?i know the 502 is bigger ci wise but they share alot of the same parts.anybody modified a 454 mag with any satisfactory results.i'm interested in keeping the efi thats what caught my eye the most.

02-02-2012 | 03:34 PM

#43

MCKILLOP

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From: Lake Washignton

Quote:

Originally Posted by hickle44

I dont see any reason it would not work on a 454. Give Bob Madera a call and talk with him His contact info is somewhere in this thread. Bob will be able to tell you everything you need to know, including info about the emc tune from Mark

02-07-2012 | 01:33 PM

#44

hickle44

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could not find a number for bob madara.found mark boos number and web site(pmefi.com)am i missing something?really want to get some answers to get a direction for this project.sounds like these are the guys to do it.

02-07-2012 | 01:36 PM

#45

MCKILLOP

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From: Lake Washignton

http://www.marinekineticsonline.com/ for Bob, then call Mark for your tune.

02-07-2012 | 03:33 PM

#46

hickle44

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thanks for the reply.

09-05-2016 | 10:25 PM

#47

GrannySShifting

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Have any pictures of the intake manifold modified? Curious what modifying the runners looks like

09-06-2016 | 11:06 AM

#48

articfriends

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From: frankenmuth michigan

Quote:

Originally Posted by GrannySShifting

Have any pictures of the intake manifold modified? Curious what modifying the runners looks like

Flame arrestors and throttle body's are a big deal on these mpi motors too, avoid any aftermarket FA that has a adapter that necks down as on my dyno they KILLED hp over stock FA. IF you mod intake invest in bored out throttle body, it greatly complements the intake mods. Cam is important too, the cam 502's and 454smpis have is a terrible, low lift hp killer. Dont bother modding intake if your keeping stock cam, FWIW, Smitty

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