200whp with stock N/A rotating assay? by ForcedFirebird

3 minute(s) of a 31 minute read

It's nice to have the equipment needed to test things.

Newest comparison of data.

You already saw the first three tests. .500 lift was removed to avoid confusion, and the fact that we will not see lift that high. Pay attention to the mid lift areas (under .300") as well as the average flow. Many people get confused and just want to see high numbers, but in fact it's more important WHERE the gains are. The valve sees mid lift twice per valve reciprocation, so peak numbers aren't as important as area under the curve (much like dyno numbers).


Test #1 is a stock bare head with test jig.

Test # 2 is a stock head with the stock intake and TB attached.

Test #3 is a stock head with the ITB's

Test #4 is a stock port, no induction (bare head with test jig) and a 1mm over sized valve. Take note of the mid-lift numbers.

Test #5 is a stock port, again no induction, custom valve job to suit the over sized valves.

Test #6 is same as test #5 with the ITB's added.

Test #7 is also the same as #5 and #6 with some port testing and doing some simple touching of the ports where needed. Almost NO material removed. Not even enough to make a pile.




I have a feeling by doing a little to the manifolds without removing much material, we could see a little more, even, but this is good enough in my opinion. The gains were moved into all the correct lifts. Boundary layer is a good friend of mine. Creating flow and velocity and not increasing port volume by much is a wonderful thing. Do what needs to be done, where it needs to be done can have great effects. "Hogging out" and removing large amounts of material isn't always best for any given situation.

Also, take note of the over sized valve flow. Sure one would think adding bigger valves is better (bigger is better, right?), but, the bench doesn't lie.

Now to finish the head up, get it on the car and let's see what the dyno says.

Unless you want to flow test heads, yes, leave them alone. Been saying that for years. Even if test #7 was explained, it's not the same as real world testing. Besides, let's see if the dyno backs up all these years/tests. These gains/tests are a joke to most, and would laugh at a goal of 200hp. My machinist always laughs at me since he has a 2000+hp drag car, but it is what it is. Just a small shop trying to get hp from a 25+yr old platform for not a lot of money.

It's coming. It really wasn't happy with the modifications as it sat, but it's driving around as of now.