Whats the differance between 2v and 4v heads? Thanks.

 

2V=two valves per cylinder, intake and exhaust; 4V=4 valves, two intakes and two exhausts.

The 4V configuration allows for smaller, lighter valves with reduced inertia which can operate at higher speeds without float compared to the larger 2V valves. In addition, the configuration allows for more port area which gives a higher flow rate.

So, the combination of lighter valves and larger ports makes for more potential power at higher rpms.

 

Hmmm guess I should have said (in relation to pre 70's engines). I did some research and what I was referring to was the 4v vs 2v heads that both had 2 valves, the 4 v being produced for a 4 barrel carb, hence larger intake ports, and larger valves.

 

Carburator engines. 2v is a 2 barrel carb, 4v is a 4 barrel carb.

 

The 2V/3V/4V nomenclature usually relates to the later model engines employing two, three or four valves per cylinder. Carb nomenclature for the earlier 2-valve pushrod or OHC engines was usually 2BBL or 4BBL, the reference being obvious.

Depending upon the application cylinder heads were usually the same for either carb configuration; the 2BBL or 4BBL nomenclature was in reference to the intake manifold; however, many hi-po 4BBL applications did have larger ports.

 

so bbl stands for barrel?

 

You have it.

 

2-4=-2 so -2 is your difference or 4-2=2 1 dollar bob. sorry couldnt help myself