head flow potential

[reds89]

just a general type question,what has the greater effect on flow rates/horsepower,
high valve lift short duration or longer duration low valve lift and does the lobe separation angle effect it as well.
seeing that i,m buying a set of 170 pro1 heads they can be used as an example.

[Awesome Bill]

If your using the wider lobe sep, this calms the intake charge down a little and creates a broader torque curve. With the tight lobe seps, this creates a very peaky torque curve. The larger the engine the peaky torque curve happens quicker. For street use always be conservative. Engines like smaller not larger almost 99% of the time. We always think some is good and more must be better. This is a very open question and there can be a ton of answers depending on exactly what you want to do.

[reds89]

thanks bill,thats answered my question ok,i am building an engine for my f150 using the dart pro1 heads with the 1.94 valve and a fairly mild street type cam as quoted by the cam manufacturer so i,m hoping all goes together ok.
from what you have said i dont think i,ll be far of the mark.thanks again.

[Nova67ss]

Hi there Bill.

wounder what possible flow I might have on my Dart sportsmen II heads?

Its the erly -90 with angle plugg and 64cc heads 200cc intake
They have been cc´d and some minor cleanup from misses in the manufakturing process NOT to be called port jobb

They where prepped for a 10:1 comp engine with a Perf RPM intake 700cfm vac holle and the edelbrook RPM cam, and the full length hooker super comp headers with 1,5/8 primary tubes..

[Awesome Bill]

Should be around .500 lift 225/240 air flow depending on cylinder bore and the work done. The exhuast most likely around 160/170. Very good heads.

[Nova67ss]

Thanks Bill.

[Awesome Bill]

No Problem.