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Carburetor 2 barrel to 4 barrel what is required for upgrade

srazac

New member
"I have a 2000 5.0L Mercruiser

"I have a 2000 5.0L Mercruiser with a 2 barrel carburetor. I would like to move to a 4 barrel for more power. Appreciate your input as to what modifications are required to the engine to achieve this. Is it a good idea?
I found a good deal on a reconditioned Rochester brand 4-barrel carburetor that was intended to be used on a GM Crusader 454 Engine- 350 HP. Could this work? See pictures
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"
 
"You need a manifold i believe

"You need a manifold i believe, maybe a cam, dunno
and watch your gas go down twice as quick"
 
You'll also need the throt

You'll also need the throttle cable bracket. That 4BBL looks like it belongs in Davey Jones' locker; get a merc. reman. or a new Holley. You will only get 15-30 more HP.

If you want more "hole shot" then get a 4 blade prop 1 pitch lower than what you have now.

What is your current WOT RPM? If you aren't near 4800 RPM then drop the prop pitch or go to an SS prop.
 
"[b]"That 4BBL looks like

""That 4BBL looks like it belongs in Davey Jones' locker; get a merc. reman."

Ayuh,...

Buy an Edlebrock Performer,...
They're exact carbon copies of the Merc./ Weber carbs Merc uses..."
 
"Hi, I see some 4.3 liter V6 m

"Hi, I see some 4.3 liter V6 mercruiser engines rated 205hp verses the standard 175hp.I have two short blocks,one is a 1987 the other is a 1990.Are the blocks the same , as well as the heads,and is the hp. difference just the carb. and manifold?Thanks"
 
"Sorry,I goofed,I was reading

"Sorry,I goofed,I was reading yours and went straight to post instead of starting a new disscussion."
 
"Hi Ray, hopefully i'm not

"Hi Ray, hopefully i'm not to late, but a 454/350hp 4bbl carb wont work because the Metering Rods and jets would be too much for the 305ci 220hp engine. You can have it re-jetted if you already own it."
 
"Hi Ray, also the other issue

"Hi Ray, also the other issue is Choke, it doesn't look like it has an electric choke and the one from your 2bbl carb wont bolt up. then you'll also need to swap out your intake manifold (unless it is a 4bbl "speadbore" type)"
 
Ray. To go thru all that work

Ray. To go thru all that work and be that close to the cam? Horsepower and boating adds up to big bucks. Do your homework. Find out from others what hp gains can be had and what speed was gained.
 
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