efi to carburator swap

[business215]

i have a 1996 454 mag efi motor I want to put in place of 1998 454 non mag carb motor I need to keep the carb set up but I am told the intake won't bolt up to the efi heads.Does anyone know of a intake that will work where I can use the carburator set up that I have

 

[lcboater]

The mag engine has rectangle port heads and the other engine has oval ports. You need an intake for rectangle heads and your carb set -up will work.

 

[mkhammer]

i have a 1996 454 mag efi motor I want to put in place of 1998 454 non mag carb motor I need to keep the carb set up but I am told the intake won't bolt up to the efi heads.Does anyone know of a intake that will work where I can use the carburator set up that I have

I have a used stock Iron dual plane 454/502 Mag carb rectagular port intake manifold for sell.
It's in perfect condition I took it of a boat that had only 50 fresh water hrs on it.

If interested I can post a pic, $150.00 + shipping

 

[wizard8575]

Im not sure if its true for marine motors or not but I know on car efi and carb motors have different cams.

 

[business215]

I have a used stock Iron dual plane 454/502 Mag carb rectagular port intake manifold for sell.
It's in perfect condition I took it of a boat that had only 50 fresh water hrs on it.

If interested I can post a pic, $150.00 + shipping

I am interested do you know if the carburator that came on the non mag motor will bolt up to it I'm not for sure what type carb is on it.This is a boat I am putting together to sell,I will have to ask the guy doing the work for me what carb is on it,I don't know if they have different bolt patterns

 

[mkhammer]

I am interested do you know if the carburator that came on the non mag motor will bolt up to it I'm not for sure what type carb is on it.This is a boat I am putting together to sell,I will have to ask the guy doing the work for me what carb is on it,I don't know if they have different bolt patterns

Post a picture of your carb bass. It will say on the carb what it is, Holley, Weber, Rodchester, ect, I could not tell you without looking at it. The manifold I have came with a 750 Weber on it .

You can post a pic through Photobucket or email it to me: michael@mkhammer.com

 

[mkhammer]

Im not sure if its true for marine motors or not but I know on car efi and carb motors have different cams.

This is true the stock efi cam is ground on a 116 lobe center I believe on that engine, I would have to look it up to be sure, and the carb cam is on a 114.5. a carb would still work but not as good as the efi. If your boat was originaly equiped with efi I would not change it without changing the cam if you haven't already. This is a good point and you still have your intake off put a new cam in it that will work with the carb.
I would much rater Have a EFI engine for many reasons,So I take it you have the long block only and no EFI components. The intake I have is rectangle port if you have oval efi heads you just have to get a Oval port intake.

You need to give more information.

 

[boatn70]

just curious

why do you need to keep the carb setup as on your original motor. couldnt you drop in the whole efi setup, i know you may need a different wiring harness or something but i think youd like it.

theres a Dart aluminum intake, like brand new, on boatfreaks.org for 250, youd still need a carb.

 

[ezstriper]

a performer RPM air gap would be the best, use a 750-800 cfm holley DP, cam will be fine...Rob

 

[mkhammer]

1996 454 mag efi, will not run as good with a carburetor on it. It will run but you will loose a lot of bottom end power. A victor Jr. air gap or a Dart rectangular port intake will work. The dart is what comes on a factory Mercruiser 500 HP carb engine with a 800 cfm dp Holley marine carb. A 750 will work fine on your 454. but if you want it to run right you need to change the cam. You need a cam ground on a 112 lobe center 216 dur./550 lift on the intake
230 /592 exhaust or specs near this on a 112 Lc if you want it to perform right.
Now is the time to change the cam before disapointment is experianced.
Both your engines should have roller hydraulic lifters, you can use them over and just buy a new stick if you are on a budget. I can sell you roller hydraulic cam that will make power for $200.00
Or a complete performance hydraulic roller cam kit with with hydraulic roller lifters for $775.00, With race hydraulic roller lifters 975.00.
If for some reason you you need a flat tappet hydraulic cam I have cam and lifter kits.$225.00
Regardless of what I am offering I would change the cam no matter where you buy it.

 

[business215]

1996 454 mag efi, will not run as good with a carburetor on it. It will run but you will loose a lot of bottom end power. A victor Jr. air gap or a Dart rectangular port intake will work. The dart is what comes on a factory Mercruiser 500 HP carb engine with a 800 cfm dp Holley marine carb. A 750 will work fine on your 454. but if you want it to run right you need to change the cam. You need a cam ground on a 112 lobe center 216 dur./550 lift on the intake
230 /592 exhaust or specs near this on a 112 Lc if you want it to perform right.
Now is the time to change the cam before disapointment is experianced.
Both your engines should have roller hydraulic lifters, you can use them over and just buy a new stick if you are on a budget. I can sell you roller hydraulic cam that will make power for $200.00
Or a complete performance hydraulic roller cam kit with with hydraulic roller lifters for $775.00, With race hydraulic roller lifters 975.00.
If for some reason you you need a flat tappet hydraulic cam I have cam and lifter kits.$225.00
Regardless of what I am offering I would change the cam no matter where you buy it.

Thanks I appreciate all of the information I will be talking with the man thats working on it Tuesday with the information you have gave me and find out which heads and carb is on it,than I will get back with you on which intake and cam I need.You are correct on me not having all the parts I would need to go back efi and this is a boat I am selling so trying to get together as cheap as I can but still want it to run as good as it can.Again thanks for the help!

 

[mkhammer]

Thanks I appreciate all of the information I will be talking with the man thats working on it Tuesday with the information you have gave me and find out which heads and carb is on it,than I will get back with you on which intake and cam I need.You are correct on me not having all the parts I would need to go back efi and this is a boat I am selling so trying to get together as cheap as I can but still want it to run as good as it can.Again thanks for the help!

A snappy good running boat will sell when they drive it. If a potential buyer is out test driving boats and youir runs strong they will buy it over a doggie one.

 

[business215]

A snappy good running boat will sell when they drive it. If a potential buyer is out test driving boats and youir runs strong they will buy it over a doggie one.

I will be in touch with the mechanic working on it tomorrow and than I will be back in touch with you,again thanks

 

[boatn70]

FYI

im prety sure i have a set of NEW take out stock chevy lifters from my 502, with retainers (dogbones) and even the splash plate from on top.
would sell very reasonable!

 

[mkhammer]

That is a good offer for some Gen VI lifters, I can hook him up with a bump stick and he would be in business.

 

[business215]

That is a good offer for some Gen VI lifters, I can hook him up with a bump stick and he would be in business.

I talked with the mechanic today and he checked and said that it has the rectangular port heads on it so I am interested in the used intake that you have I will let you know in the next day or two.There is something else you might be able to help me with,to start with the efi motor that I am putting in I bought with a procharger set up on it at the time I bought it for the procharger it being on the same setup that I have in my checkmate so I am keeping that for my boat,but when the guy put it on he didn't keep the original parts he took off the motor,I don't know forsure what all parts those are I believe he called it the fuel separater I am checking on that now.If I could find the parts I needed used for around or at least close to what it cost to change over to the carburated set up I would prefer to go back fuel injected.I hope to know what all that is in the next day or two.If you can help with any of these things I am interested.I will be back intouch as soon as I know more,Thanks

 

[mkhammer]

I talked with the mechanic today and he checked and said that it has the rectangular port heads on it so I am interested in the used intake that you have I will let you know in the next day or two.There is something else you might be able to help me with,to start with the efi motor that I am putting in I bought with a procharger set up on it at the time I bought it for the procharger it being on the same setup that I have in my checkmate so I am keeping that for my boat,but when the guy put it on he didn't keep the original parts he took off the motor,I don't know forsure what all parts those are I believe he called it the fuel separater I am checking on that now.If I could find the parts I needed used for around or at least close to what it cost to change over to the carburated set up I would prefer to go back fuel injected.I hope to know what all that is in the next day or two.If you can help with any of these things I am interested.I will be back intouch as soon as I know more,Thanks

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