Switching from Volvo TBI to Carb on a 1996 5.7 GI

[Scott Danforth]

the other thing for more power if that is your goal. upgrade the heads to vortec. your boat may be a 1996, however the picture in post 16 is of a 1986-1995 intake (non-vortec). most likely your motor has 1991-1995 swirl port heads

if your block is an 880 block, then your motor is a 1995 motor may be a roller motor.

vortec heads are good 40hp over the swirl port heads.

 

[camboat]

That would be great! Should I put a regulator on it or use it as is?
That will help keep everything looking stock using the low pressure pump and filter setup.
Thanks for the info

 

[Scott Danforth]

That would be great! Should I put a regulator on it or use it as is?

depends on pressure. if you are over 5-6 PSI, definitely use a regulator.

 

[camboat]

Just a few more questions.
Here is a pressure regulator with attached gauge to get the fuel pressure dialed in.

Speedway Fuel Pressure Regulator 5-12 psi & Gauge 0-15 psi​

I can attach it directly to the Volvo low pressure pump and filter housing to make a clean installation.
Should I use a hard line from the regulator to the carb or will A1 fuel line work? It will be around 10-12" fuel line from the regulator to the carb.
I'm just fine tuning everything before I start ordering all my parts.

Thanks again for the help!
Jack

 

[Scott Danforth]

I prefer the Holley fuel pressure regulator. The speedway branded parts were iffy

A1 fuel hose is fine

 

[camboat]

Thanks Scott
I will do the Holley regulator.

 

[camboat]

Since I am going to use the Volvo low pressure fuel pump and Holley fuel regulator, where do I run the fuel over flow line since I will be removing the VST? Does the fuel regulator set to 5 psi eliminate the fuel overflow port?

Thanks

 

[Scott Danforth]

You return it back to the VST tank or back to the tank itself

 

[alldodge]

Since I am going to use the Volvo low pressure fuel pump and Holley fuel regulator, where do I run the fuel over flow line since I will be removing the VST? Does the fuel regulator set to 5 psi eliminate the fuel overflow port?

Thanks

Two things
Your VP low pressure pump may not need a reg, it might but might not, check/test first

The Holley Reg limits the amount of pressure going to the carb, it simply does not allow any fuel above the adjusted pressure to pass, no need to overflow line. Same thing a house water pressure reg uses

 

[Scott Danforth]

Depends on which regulator you buy. Blocking or bypass

 

[camboat]

Which one is better for this application?

 

[camboat]

Would this work for the overfull port on the 1409 carb?

 

[Lou C]

That carb had the nipple built in so you can use a standard flame arrestor

 

[camboat]

Will I started removing the old wiring harness, TBI, and fuel lines.
I have confirmed that the Edelbrock 1409 will bolt directly to my manifold. I will cap off the overflow port. It is used with a mechanical fuel pump.

I will add a Holley pressure regulator after the stock Volvo low pressure pump to make sure I have exactly what the Edelbrock requires.

I’m thinking about trying this distributor.

Davis Unified Ignition Marine Performance D.U.I. Distributors M12720BL​

Has anyone used it? It will be a simple install with the built in coil. Just two wires. If there is a better distributor for this swap to carb let me know.
Thanks

 

[alldodge]

The DUI will work and several have used it
Merc and VP used Delco EST

 

[Lou C]

If you have a stand alone Delco EST why not just use that?

 

[camboat]

Here is my distributor. Is this a Delco EST? I didn’t think I could use it with out the ecm.

Thanks for the help!

 

[alldodge]

Yes that's a EST, just use it

 

[camboat]

Perfect
You just saved me $400
Do I need to change anything on it for the carb conversion?
I will put a new coil on. The old one looks tired.

Thanks

 

[Scott Danforth]

Your old coil is just fine. Why spend money you don't need to spend