4.3 Mer---2 barrel to 4 barrel???

[175BR4.3]

Anyone here ever converted from a 2 barrel carb/manifold to the 4 barrel carb/manifold??? Besides the fact that you would use more fuel, is there any performance gains in doing this??


Any info would be great.

 

[sprink56]

Anyone here ever converted from a 2 barrel carb/manifold to the 4 barrel carb/manifold??? Besides the fact that you would use more fuel, is there any performance gains in doing this??


Any info would be great.

Look into the available options for your year/model 4.3. I believe you will find that there was a 4 barrel version offered. The easiest way to make this swap would be to use all of the original parts from the 4 barrel version. There will not necessarily be an increase in fuel consumption overall but you will realize better performance. Understandably, you will use a bit more fuel at WOT but otherwise your GPH should be very close to the 2 barrel figures.:thumbsup:

 

[wreckless123]

I was thinking the same thing over this past weekend. My 185 would really run strong with a 4 barrel. What about aftermarket parts? Someone must have done this at one time?

 

[Knotty Buoy]

The factory job had 30hp more. The 4.3LX was the 4 barrel variant.

(Idles better and no noticable difference in fuel consumption at cruising....noisier at WOT)

 

[Captain Crispy]

At 0 to about 3200 rpm, you won't see a difference because the 4 bbl will still be a 2 bbl. Once you open the secondaries, it will be a little louder, consume more fuel, and deliver more power. Not sure exactly where yours will open; on my 350 they didn't start opening until around 3200 or so.

 

[gm2iam]

See my next post, sorry for the duplicate my firewall locked me in.

 

[gm2iam]

Yes, there is a gain in HP but you will need a upgraded camshaft to go with the 4bbl. I built these marine engines for years at the factory and we used a special camshaft for the 2bbl vs 4bbl.