5.7 repower: Should I go 2 barrel or 4 barrel carb?

[Luhrs28]

Hi Guys:

I have a 1977 Luhrs 28' fiberglass cabin cruiser that I'm going to repower with a Mercruiser 5.7 (350). The question is whether to go 2-barrel or 4-barrel carb.

Will the 4 barrel just make a higher max. HP? My understanding is they would both have the same fuel economy up until the secondary butterflys open. After that the 4 barrel is going to burn more fuel.

Since I'm limited to about 250HP because of my old Paragon transmission I'm thinking I should go 2 barrel. Does that make sense?

Thank you,

Bert

 

[John_S]

Re: 5.7 repower: Should I go 2 barrel or 4 barrel carb?

I'd go 4brl which would put you near your drive max. Fuel economy will depend on howyou drive it.

 

[Monterey10]

Re: 5.7 repower: Should I go 2 barrel or 4 barrel carb?

With my 28'er,

I need the 4 barrel to get up on plane. Once on plane, I can pull back on the throttle to run with the 2 barrels. The 4 barrel carb pushes the HP up to 260 on the non vortec engines and 300 hp on the vortec motors.

You should call Paragon or some of the old time marine engine repair places, and ask them about the transmission's ability to handle a few more horses. Some transmissions were bullet proof, others not...

 

[tpenfield]

Re: 5.7 repower: Should I go 2 barrel or 4 barrel carb?

Let the Horsepower rating of the 4bbl vs. the 2 bbl versions be your guide since your tranny is a limiting factor. As I recall, most 4bbl 350's are good for about 270+ HP. The 2 bbl are more in the 230 HP range. You may want to respect the transmission and go with the 2 bbl.

 

[Bondo]

Re: 5.7 repower: Should I go 2 barrel or 4 barrel carb?

Hi Guys:

I have a 1977 Luhrs 28' fiberglass cabin cruiser that I'm going to repower with a Mercruiser 5.7 (350). The question is whether to go 2-barrel or 4-barrel carb.

Will the 4 barrel just make a higher max. HP? My understanding is they would both have the same fuel economy up until the secondary butterflys open. After that the 4 barrel is going to burn more fuel.

Since I'm limited to about 250HP because of my old Paragon transmission I'm thinking I should go 2 barrel. Does that make sense?

Thank you,

Bert
'77 Luhrs 28', repowering with GM diesel V8 and some restoration along the way

Ayuh,.... What happened to the Diesel,..??

Where's this 350 gasser comin' from,..??
Is it a new recon, with Vortec heads, er Not,..??
Are you buyin' an intake manifold, regardless, 2bbl. or 4bbl..??

I'd go with the Merc/ Weber/ Edlebrock/ Carter clone carb...
It's a square bore pattern, but the primaries are Tiny,...
Great fuel mileage, down low...
'n yes, ya get a bigger boost in Power, up higher, even though the lower end benefits as well...

So long as you've got complete control of yer righthand, yer transmission won't care....

The thing 'bout Horsepower is,...
If ya got it, 'n don't use it, it don't matter...
but atleast ya got it, when ya NEED it...