Cylinder head flow - What is crucial in a stocker?

[Randy Wells]

Originally Posted by jamie2370

What I can tell you is this. You can take a sbc stocker combo, put decent shortblock in it, do only the allowed valve job to the heads with best valves and springs, assemble with the latest greatest cam and lifters, put it in the car with a name brand carb, name brand trans and converter and I can almost guarantee you won't be within 7 tenths of the top cars with that combo. SO....heads and intake are 90% of the power. Plus if they really answered your question then they couldn't charge $5000 for a set of stocker heads and $1800 for an intake lol

What percentage of ET do you think is attributed to, suspension, shocks, weight distribution, transmission and overall set up of chassis?

Randy Wells
I/S 5628

[jamie2370]

Originally Posted by Randy Wells

What percentage of ET do you think is attributed to, suspension, shocks, weight distribution, transmission and overall set up of chassis?

Randy Wells
I/S 5628

A decent portion. In my case I am refering to a proven car that has been a second under.

[B Parker]

So, let's take a small block chevy. How much HP do you think it takes to pick up a tenth? To make it easy let's say a 69, 350/255 hp combo. BP

[Stan Weiss]

Originally Posted by B Parker

So, let's take a small block chevy. How much HP do you think it takes to pick up a tenth? To make it easy let's say a 69, 350/255 hp combo. BP

Just a rough guess. Around 12.5 HP.


Let me revise that to around 9.4 HP.



Stan

[Frank Castros]

I'm not attempting to doubt Stan's calculation but if we average it through the spectrum of the most commonly used combinations it's going to be roughly 10.0.
So of course based on the original question on flow of the intake and efficiency of the reversion on the exhaust side and based on a 88% + cylinder seal I believe you better have your ducks in a row to compete with the big dogs. One of the keys is chassis efficiency for sure.
If you can't run with big dogs, don't stay on the porch, find out why, it's not always $$$, it's dedication.

[Glenn Briglio]

Originally Posted by Stan Weiss

Just a rough guess. Around 12.5 HP.


Let me revise that to around 9.4 HP.



Stan

How did you come up with that number ?

[Larry Hill]

You want to manage the air on the outside of the car as well. Case in point on the truck the bed was off to one side. We centered the bed behind the cab and it picked up a little in et and MPH. An easy way to cheat is to cheat the wind.

[Stan Weiss]

Originally Posted by Larry Hill

You want to manage the air on the outside of the car as well. Case in point on the truck the bed was off to one side. We centered the bed behind the cab and it picked up a little in et and MPH. An easy way to cheat is to cheat the wind.

Yes anything you can do to reduce Frontal Area or Coefficient of Drag (CD) will show up in reduced et and increased MPH.

Stan

[Stan Weiss]

Originally Posted by Glenn Briglio

How did you come up with that number ?

I ran some 1/4 mile drag simulations. After I ran the first one I realized I had used to fast of a car and reran it. Both my numbers are still only guesses. It is possible Frank's number is correct. This number will vary based on the class with A/S being greater than U/S. What is the weight of the car and what does it run for both et and MPH?


Stan

[B Parker]

Originally Posted by Stan Weiss

Just a rough guess. Around 12.5 HP.


Let me revise that to around 9.4 HP.



Stan

Stan I wouldn't argue anything about machine work with you, but I disagree on the HP needed. Maybe in a lightweight car. But in my 40 plus years of running stockers I'd say more like 15 to 18HP. The point I was going to make if someone can pick up .7 with an intake and heads you must have some pretty bad heads to begin with. Just a few years ago it was 8hp difference with an intake on a small block stocker. If someone is getting much more than that I would love to see it in tec at Indy.
Using the 15 hp number to go .7 you would need to pick up 105hp. That would be 97 hp from head minus the intake. I think I use one of the best out there but if you have someone that can get me 100 hp from a set of heads please let me know. BP