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-   -   mpi to carb conversion (https://www.offshoreonly.com/forums/general-q/253822-mpi-carb-conversion.html)

JasonSmith 05-18-2011 08:38 PM

It still amazes me you guys are spending thousands of dollars to go backwards.
EFI ain't that difficult if you know the right people.
To each his own.

nailit 05-18-2011 08:53 PM

I thought about also, but stayed with efi!! Can't beat turning key and crack!! No pumping lever ever...

Prop less, I bought the merc kit that added an aux pump and cured my vapor lock for $100... Easy plug n play!

morrowcarl72 05-19-2011 12:41 AM


Originally Posted by jeffswav (Post 3406816)
x2 thats what I use

jeffswav i know you are a big name on this site and you have helped me before so what can you tell me about the hei distributors.... the mechanic at my company runs one on his circle track car and said the same thing....

drop the need for a coil i get that but what about a ignition box....


i have been told edelbrock performer air gap single plane + 800cfm holley marine 0-9022 carb......


my question is do i need a box if i use that or just the hei distributor carb and intake?

morrowcarl72 05-19-2011 01:04 AM

also any thoughts on a particular intake manifold?


someone told me to go with a airgap which seems good power 1500-6500 but im pretty sure everyone on here says single plane.....

remember this is just a roller 502 with retangle port heads

looking for drivability, not a huge fuel loss, and reliability!

Griff 05-19-2011 01:12 AM

Air Gap manifold is also a good choice. It is a dual plane and I doubt you will loose any top end power with it and your combo.

1BIGJIM 05-19-2011 06:17 AM

I am sure more people are running dual than single plane intakes manifolds when running in the 5,000 RPM range.

I have RPM Airgap, RMBUIILDER cams, and Holley 800 D.P.
jetted up to 78 -91 with power valve, and thunderbolt ignition set at 34 degrees.

I turn it up to 5,200 and that manifold works great.

ezstriper 05-19-2011 06:25 AM

no with the HEI you do not need a box, just drop it in and run...ran one a bunch..and you guys can have your $500 tune...and sending back and forth trying to get it right...both setups have their advantages..just have to asked yourself whats it worth to you...

morrowcarl72 05-19-2011 10:04 AM


Originally Posted by 1BIGJIM (Post 3407106)
I am sure more people are running dual than single plane intakes manifolds when running in the 5,000 RPM range.

I have RPM Airgap, RMBUIILDER cams, and Holley 800 D.P.
jetted up to 78 -91 with power valve, and thunderbolt ignition set at 34 degrees.

I turn it up to 5,200 and that manifold works great.

hey what kind of motor are you running? what kind of hp? boat? mph?

jeffswav 05-19-2011 08:53 PM


Originally Posted by morrowcarl72 (Post 3407070)
jeffswav i know you are a big name on this site and you have helped me before so what can you tell me about the hei distributors.... the mechanic at my company runs one on his circle track car and said the same thing....

drop the need for a coil i get that but what about a ignition box....


i have been told edelbrock performer air gap single plane + 800cfm holley marine 0-9022 carb......


my question is do i need a box if i use that or just the hei distributor carb and intake?

The DUI is a all in one, cap, coil, rotor and modual. No box needed, most I have spun it up to is 5600 RPM. I have run it 2 seasons and no corosion or rust like you get with MSD. I have the electronic advance version but the mechanical work well also. I kind of agree with Jason, I like MPI, starts better, quicker, better fuel economy, ect.... I however use the Holley Aftermarket system so I can program mine on the fly with the laptop. The merc comp needs to be programed by a pro.

skydog 05-19-2011 09:18 PM

When I boat my boat I wanted cards!!! Here so many problems with efi and big power. Boy I could not be happier!!!! Turn key all day and has not missed one beat!!! LOVE IT!!!! Boost and cards just works great. Like must better than tuning with a map sensor. Do it u will not look back.
Skydog


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