I just got my heads back from being bench tested to pick a cam for my 434 build. I have CHI 2V heads with a 2.053 dia intake valve and a 1.654 dia exhaust valve. Here are the numbers I got:

Intake Exhaust Percentage Ex/Int

.100 67.4 52.0 77.2%
.200 126.8 91.5 72.2
.300 174.6 130.2 74.6
.400 222.8 159.6 71.7
.500 258.0 180.7 70.0
.600 280.8 194.1 69.1
.700 288.4 205.1 71.1

These are pretty good numbers! I will be picking a Cam next and soon will be finishing my 434 and will have it Dyno'd.

 

I like the consistency. The stock 4v heads are about 10% less throughout range so they are definitely putting out numbers. The stock 2v heads appear to flow a little better at low lift but then die and the 'cnc ported' 2v oz heads kick everyones hiney at lift up to .40 then die off as well.

how do those power up in the d.dyno with the 334. amazing i bet.

 

I haven't Dyno'd the engine yet, but I want to run some numbers on a desktop dyno just to get an idea.