I am about to order some pro topline heads and should I go with the 180cc or the 200cc? The flow numbers from the two heads seem to be similar.

200cc:
.300 .400 .500 .600 .700
191.63 235.96 260.98 268.51 278.41 Intake
156.94 176.85 186.34 190.13 194.87 exhaust

180cc:
.300 .400 .500 .600 .700
206.86 242.68 257.90 263.27 270.12 Intake
156.94 176.85 186.34 190.13 194.87 exhaust

These heads will be going on a 350 with Holley stealth ram and a comp cam XE 224/230 .536/.544 112 @.05. I kind of already asked this question but after doing a lot of reading it has me questioning my original choice, the 200cc. The 180cc seem to flow more on the lower lifts, but are not too far behind the 200cc after .500. Desktop dyno actually has the 180cc making more power. So what do you guys think?

 

I would tend to agree with Desktop Dyno on this one. IF those are the actual flow numbers.

If you have a choice of 2 heads that flow the same but one has smaller intake ports, go for the smaller ports. They keep intake velocity up which helps pack more mix in the cylinder on every intake stroke.

 

The 200cc runners will provide better top end power and the 180cc runners will provide better low end power; simple as that. Even if the flow numbers are similar the dyno sheets will end up reflecting the intake runner volumes.