5.0 swap to 5.7 what carb is the best

[Swmoose]

I have a four winns 1999 180 that had a frozen 5.0. I just purchased a 5.7 marine crate engine and would like to know the best carb to go with that will bolt up and use same choke and fuel system as i have. Its an electric pump to a 2barrel with electric choke. The intake just had a cover plate on the extra ports so looks like i can bolt it up easy. Do i need a spacer or anything under the new carb also? Thank you

 

[Lou C]

If you want to stick with a 2bbl you can go with a Holley 2100. However if I were doing it I’d get a 4 bbl manifold and use either a Holley or Edelbrock (on back order now). I actually prefer the Quadrajet 4bbl but good cores are hard to find. I happen to have a good original on my 1988 4.3 V6.

 

[Swmoose]

I would like to go 4barrel. What model number would be best? Is the electric choke the only thing i have to worry about when selecting one? I heard 600 to 650 cfm is best

 

[Lou C]

Both the Holley & Edelbrock use an electric choke so no difference there. If you use the standard cast iron intake you need an adapter (spread bore manifold & square bore carb). You can use an Edelbrock 1409 or a Holley 4160.

 

[kenny nunez]

edl-1409 Edelbrock at Summit. $545.95. 600 CFM

 

[Scott Danforth]

I would do a 650cfm holley 4150 vac secondary.

Volvo used to put 715 cfm carbs on the AQ271's and AQ311's

I would also add a 2" carb spacer if you have the room. The extra plenum volume adds mid-range

 

[Swmoose]

I would do a 650cfm holley 4150 vac secondary.

Volvo used to put 715 cfm carbs on the AQ271's and AQ311's

I would also add a 2" carb spacer if you have the room. The extra plenum volume adds mid-range

Ok thank you

 

[jimmbo]

Holley does make a 4175 650CFM Spreadbore Marine carb. https://www.holley.com/products/marine_and_powersports/marine/marine_carburetors/parts/0-80552

I have used it on my Volvo 5.7. It gave me about another 400 - 500 rpm over the stock Holley 500CFM(370 CFM, when Flow Rated as 4bbl) 2bbl. I had to increase the Pitch to bring the RPMs back with the RPM Range. The small Primaries, helped keep the Low End Torque, as the longer Prop did load the engine more at low RPM.
Volvo also, at one time, used a Holley 4175 on their 5.7's

 

[kenny nunez]

Remanufactured Quadrajets @ Summit
Jet-33004. 650cfm. Divorced choke. $419.00
Jet-33005. 750cfm. Electric choke. $419.00
Edl-1410. 750cfm. Electric choke. $545.95
If your manifold on the new engine is the spread bore style you will save some some money with the rebuilt Qjets.
The only problem is the 650 model is not available with electric choke.
As SD said about the 715 on the Volvos, you would probably get by with the 750 Qjet. Your engine is only going to pull what it needs even if the 750 is more than it needs with vacuum secondaries.
New Holleys are really pricey. You might try googling them for a rebuilt.

 

[Lou C]

I noticed that the price of Holley carbs has really gone up, some are pushing 750-800 bucks.
Looks like the Edelbrock 1409 is still out of stock from Edelbrock including remanufactured ones, but you can get the 1410, which is a 750 CFM carb, not sure if that's too much for a 5.7.
The reman Q-Jets look attractive but I wonder if they can be a mixed bag seeing as how old the cores are now, no new ones have been made in like 30+ years....I have a good original, and it is an excellent carb when in good shape and set up correctly.

 

[Swmoose]

edl-1409 Edelbrock at Summit. $545.95. 600 CFM

Thank you

Holley does make a 4175 650CFM Spreadbore Marine carb. https://www.holley.com/products/marine_and_powersports/marine/marine_carburetors/parts/0-80552

I have used it on my Volvo 5.7. It gave me about another 400 - 500 rpm over the stock Holley 500CFM(370 CFM, when Flow Rated as 4bbl) 2bbl. I had to increase the Pitch to bring the RPMs back with the RPM Range. The small Primaries, helped keep the Low End Torque, as the longer Prop did load the engine more at low RPM.
Volvo also, at one time, used a Holley 4175 on their 5.7's

ok thank you. Also are intake gaskets marine specific?
My intake is the original off the 5.0 1999 Vortec. How would I know if i could put a spread bore carb on it?

 

[kenny nunez]

Are the holes the same size or the rear are much larger than the front?
4 even sized holes are what the Edelbrock fits on and most Holleys. Large secondary are primarily for Qjets and some Holleys.
Carburetor gaskets are all the same, marine/auto.

 

[Scott Danforth]

How would I know if i could put a spread bore carb on it?

if you have two kidney bean holes where the forward holes are 1.75" and the aft holes are 2.25", then you have a spreadbore. if you have two slots, both 1.75" wide you have a square bore.

 

[jimmbo]

This the factory Intake off of my 2002 VP 5.7. It is a 4bbl intake with an Adapter to mount the 2bbl Holley. I have installed a Holley 650 Spreadbore on it. It is currently using the Original 500(375cfm if flow rated like a 4bbl)CFM Holley 2bbl.