454 MPI upgrades...

[SickSation]

I know most of you will recommend doing an engine swap, but im lookin for some additional bolt on power. I currently have a 454 gen VI MPI (non MAG). Im basicly wanting to put aluminum rect. port heads, better cam, 454 mag or 502 intake, inj., ecu, and headers. My question is, what kind of Hp increases can i expect to see? Am i approaching this at the right angle so to speak? Id really like to stay with EFI. Im getting headers soon. Im sure that will help quite a bit. Im not getting into the bottom end, so im not lookin for too much power ( forged crank). Anyone have recomendations for what heads, cam , ect I should go with? I have a friend with a Baja272 that might be a bit faster than my sunny 25ft ( havent ran the boats together yet), but I cant let a Baja beat me. No offense to the Baja guys, There just very trendy here in Indiana. Thanks in advance.

[Knot 4 Me]

Find a low hour 496 MAG HO. Sell your existing motor. Turn the key and enjoy boating. If you insist on trying to polish a turd, do a search here and on that other site with offshore in the tltle. Plenty of existing threads on this very topic. Good luck.

[MOBILEMERCMAN]

I think the intake will be the limiting factor. I too wouldn't mess with it. Add a whipple or go bigger inches like the 496. It would be a shame to spend time and money for little or no gain.

[SickSation]

Find a low hour 496 MAG HO. Sell your existing motor. Turn the key and enjoy boating. If you insist on trying to polish a turd, do a search here and on that other site with offshore in the tltle. Plenty of existing threads on this very topic. Good luck.

I will do a motor swap eventually, but Im just interested in freeing up some power iin this restricted engine. The main integrity differences in this versus a mag is the crank correct? And that shouldnt be an issue unless i put alot more power to it than i am planing for. You dont think a set of nice heads, mag intake, cam, and ext. headers are worth doing? This is a solid 290 hr motor. Im open to all opinions. Thanks again.

[SickSation]

I think the intake will be the limiting factor. I too wouldn't mess with it. Add a whipple or go bigger inches like the 496. It would be a shame to spend time and money for little or no gain.

Wouldnt a blower be a bit too much on the stock bottom end?

[MILD THUNDER]

Wouldnt a blower be a bit too much on the stock bottom end?

I'd say yes. And for what you will spend on a blower kit, you'd be better off yankin your motor, and dropping in a 502MPI or HP500 the selling yours. Lots of good takeout motors around at fair prices.

[SickSation]

I'd say yes. And for what you will spend on a blower kit, you'd be better off yankin your motor, and dropping in a 502MPI or HP500 the selling yours. Lots of good takeout motors around at fair prices.

Fair enough. Majority rules. I guess i'll be patient and look for a motor. Thanks for your opinion.

[MILD THUNDER]

I will do a motor swap eventually, but Im just interested in freeing up some power iin this restricted engine. The main integrity differences in this versus a mag is the crank correct? And that shouldnt be an issue unless i put alot more power to it than i am planing for. You dont think a set of nice heads, mag intake, cam, and ext. headers are worth doing? This is a solid 290 hr motor. Im open to all opinions. Thanks again.

You might have the newer style heads on that motor, and they arent as bad as the old peanut ports. You can do a cam upgrade, roller rockers, and get yourself some takeoff used 496 aluminum exhaust manifolds(cheap and flow well). I think you can buy a adjustable fuel pressure regulator. You can make 375-400HP with these, but thats about it using the stock induction and fuel system. I know a guy who has installed a 454 mag cam in his 7.4 mpi, and gained 300 rpm and 3-4mph. I'd think with the cam, exhaust, and roller rockers 4-5 mph should be within reach. You''ll need to upgrade your valve springs as well. All in all, you can prob do this for under 1k bucks if you do your own work.

[SickSation]

You might have the newer style heads on that motor, and they arent as bad as the old peanut ports. You can do a cam upgrade, roller rockers, and get yourself some takeoff used 496 aluminum exhaust manifolds(cheap and flow well). I think you can buy a adjustable fuel pressure regulator. You can make 375-400HP with these, but thats about it using the stock induction and fuel system. I know a guy who has installed a 454 mag cam in his 7.4 mpi, and gained 300 rpm and 3-4mph. I'd think with the cam, exhaust, and roller rockers 4-5 mph should be within reach. You''ll need to upgrade your valve springs as well. All in all, you can prob do this for under 1k bucks if you do your own work.

Now that sounds perfect. I can get a 502 Mag intake complete. Injectors, ecu, everything for 500.00. Would this help much? Ive heard the stock MPI intake is junk.

[SickSation]

Do heads, cam or intake from a 496 Ho fit a 454? Ive heard they dont, but just want to verify. The marina behind my shop is building an HO with some goodies from Raylar so all the stock parts are available...

[MILD THUNDER]

Now that sounds perfect. I can get a 502 Mag intake complete. Injectors, ecu, everything for 500.00. Would this help much? Ive heard the stock MPI intake is junk.

I dont think you will see big gains over the stock mpi you have with a 375-400hp motor, but for 500 bucks, I think its a good idea. You'll have to stay on the conservative side for a cam, because a 454 with cast internals, i'd say to keep it 4800-4900 max rpm. Going to a long duration cam will only move the powerband higher. So you'll need a cam that will make good power down low. I would think this cam would work nice. Not too radical. Should idle real well, and not have reversion issues.

http://www.summitracing.com/parts/CCA-01-445-8/

[SickSation]

I dont think you will see big gains over the stock mpi you have with a 375-400hp motor, but for 500 bucks, I think its a good idea. You'll have to stay on the conservative side for a cam, because a 454 with cast internals, i'd say to keep it 4800-4900 max rpm. Going to a long duration cam will only move the powerband higher. So you'll need a cam that will make good power down low. I would think this cam would work nice. Not too radical. Should idle real well, and not have reversion issues.

http://www.summitracing.com/parts/CCA-01-445-8/

Do you have any suggestions on what rockers and springs? Sorry for my lack of knowledge. I wrench on my own stuff, but i dont build motors. Thanks again.

[MILD THUNDER]

Do heads, cam or intake from a 496 Ho fit a 454? Ive heard they dont, but just want to verify. The marina behind my shop is building an HO with some goodies from Raylar so all the stock parts are available...

i wouldnt go crazy swapping heads, etc. Dont try making this motor into a 500HP fire breathing 454. I'd do a simple cam swap, valve springs, bump the fuel psi, install some better exhaust manifolds and call it a day. Spending 500 bucks to maybe 1k bucks is ok. But dropping 3-4k into this motor in bolt on's is a waste of money. It kinda is what it is. I know where there is a fresh 0 Hour mercury racing HP500. You can probably get it for 7k. Its complete. Bolt that sucker in, and sell off your motor. You will be ahead money wise and performance wise in my opinion! Not to mention, if you decide to sell your boat someday, a mercury blue motor adds value. Nobody will want a hopped up 7.4.

[MILD THUNDER]

Do you have any suggestions on what rockers and springs? Sorry for my lack of knowledge. I wrench on my own stuff, but i dont build motors. Thanks again.

Whatever cam you go with, they will provide spring specs to go with the cam you choose. As for rockers, a good set of 1.7 rollers with poly locks will be fine. I like the trusty old Crane Gold ones!

[SickSation]

i wouldnt go crazy swapping heads, etc. Dont try making this motor into a 500HP fire breathing 454. I'd do a simple cam swap, valve springs, bump the fuel psi, install some better exhaust manifolds and call it a day. Spending 500 bucks to maybe 1k bucks is ok. But dropping 3-4k into this motor in bolt on's is a waste of money. It kinda is what it is. I know where there is a fresh 0 Hour mercury racing HP500. You can probably get it for 7k. Its complete. Bolt that sucker in, and sell off your motor. You will be ahead money wise and performance wise in my opinion! Not to mention, if you decide to sell your boat someday, a mercury blue motor adds value. Nobody will want a hopped up 7.4.

Hp500 and EFI or Carb?

[MILD THUNDER]

Hp500 and EFI or Carb?

Its the carb version. 470HP at the prop.

[SickSation]

Its the carb version. 470HP at the prop.

HHHMMMM... Where is the motor located?

[Knot 4 Me]

A HP500 (carb) or a 500EFI would be great motors to swap in. However, keep in mind you will then have to have tailpipes made for the headers. If you find a HP500 and it still has the original Gil manifolds/risers you should consider replacing them with CMI E-tops or something similar.

[Magic Medicine]

HHHMMMM... Where is the motor located?

Shogren has a 500 hp.

[SickSation]

Shogren has a 500 hp.

Not sure who he is. Sorry, kinda new to the forums. Wheres he located?