Heads *head scratcher*

[94m6z28]

maybe i am missing some thing ovious but i dont get it, it has been recommened that i use *atleast* 210cc heads on my boosted 383 build, but when i compair flow numbers between the 3 heads im looking at, the smallest of them have over all, better flow numbers (int and Exh)

could some one explain to me what im not getting?
isent larger all around better?

[jakesz28]

You can't compare different companies flow numbers. Some companies can inflate the numbers fairly easily. But lets just say they are actual numbers if the bore size was different it would change the cfm rating slightly. Some companies set up there floe bench for a 4.030 bore and someone else may have set it a 4.125 bore. The inches of vacuum they were at could also tweak the numbers some.

Not for sure if that helps you or not but you are better off to pick a company and tell them what you want and see what they think will work the best. It's not all about flow numbers either.

[94m6z28]

well i on the AI Site it says with 4.030 bore. the 195 comps are 4.060 and the 210's dosent say

on a turbo motor, how much will Exhaust flow numbers effect my abilty to make power?

would a larger runner volume have a LARGE effect on out of boost drive abilty

[Fire67]

Bigger isn't always better. It really depends on the intended application, too big of a runner volume WILL affect part throttle driveability. But for an all out race application driveability isnt a concern.

When a motor will spend the majority of its life in part throttle, no boost situations (more street than strip), you need to consider intake and exhaust velocity. As this is what actually fills the cylinders when the boost is not doing it for you. Too big of a runner will hinder velocity, and therefore hinder the ability of the cylinders to pull in the air/fuel charge when not in boost.

Runners that are too small will restrict air/fuel entering (or exhaust leaving) the cylinder regarless of the running conditions (in or out of boost). Larger motors are more likely to suffer from this, but the same can be true for a lil 350 in a wild enough applicaiton.

Your best bet, as mentioned by jakesz28, is to pick a company (or 2 for comparison sake) and discuss your realistic plans with them in as much detail as possible. That way they can help you choose the correct balance of overall flow and runner velocity.

The head choice will be directly affected by your intended use and realistic power goals. Among several other factors of course. Unfortunately for the average enthusiast, most of this is beyond our grasp. Thankfully though, there are proffesionals educated enough to understand and apply the science behind selecting proper parts for an engine combination.

[RealQuick]

Bigger isn't always better. Is that what she tells ya ? :laugh::embarassed: J/K!

[Fire67]

Is that what she tells ya ? :laugh::embarassed: J/K!

Hey!!! Watch it guy :shiner: LOL!