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Airflow chart of a factory slant six head with mods to come
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Author:  james jaggers [ Mon Jan 08, 2007 12:31 am ]
Post subject:  Airflow chart of a factory slant six head with mods to come
I will be posting airflow numbers as soon as my valves come in. We are going to use several different valves to seef what works best. These will be true airflow numbers off of a calibrated superflow 600. :?:
Author:  slantzilla [ Mon Jan 08, 2007 1:35 pm ]
Post subject: 
Cool! :D

It will be interesting to see how your info looks against other folks.
Author:  james jaggers [ Mon Jan 08, 2007 3:32 pm ]
Post subject: 
Would have done it today but I forgot the head gasket. The numbers will be posted tomorrow. It will be of stock valves and no port work. We will be flowing up tp .600 lift while the stock runners are retained.
Author:  james jaggers [ Tue Jan 09, 2007 4:22 pm ]
Post subject: 
Here are the flow numbers we got from the slant six head. Stock valve,stock runners, and yes the spark plug was in!
@62.5 degrees and 28" the numbers are pretty bad.
IN. @.100 51 EX. 31
IN. @.200 99 EX. 52
IN. @.300 131 EX. 65
IN. @.400 140 EX. 109
IN. @.500 146 EX. 114
IN. @.600 147 EX. 115

This was done on a calibrated superflow 600. We will be changing valves and doing some different things that we do on our big mopars. These are true numbers, and as you know on a naturally aspirated engine if a engine is built efficient it will produce around 2 h.p. per cfm of airflow.
One good thing is the exhaust flows 78% of the intake.
Author:  sandy in BC [ Tue Jan 09, 2007 4:26 pm ]
Post subject: 
What year is this head? What is your current chamber volume?

Will you be doing chamber mods to unshroud larger valves?
Author:  james jaggers [ Tue Jan 09, 2007 4:31 pm ]
Post subject: 
It is a 1968 head I can't think of the casting number of hand. The chamber is factory, it has not been milled. We are going to beat the crap out of this head. It will give up the ghost and when it does I will keep you guys posted.
Author:  james jaggers [ Sun Jan 14, 2007 7:46 pm ]
Post subject: 
We have some pics of some of the modifications to are head on are web site. Check it out,we are building these heads for a turbo. The valves are pro flow stainless. The exhaust is only a 1.45 because of the shrouding. Even though the valves are not much larger, using a bigger valve will only be shrouded. Even though we cut a lot out to deshroud around both the intake and exhaust valves. Bigger valves are not always better.
Author:  slantzilla [ Sun Jan 14, 2007 8:59 pm ]
Post subject: 
That's some great looking parts you have fabbed up. :D

I would think that on a motor with a snail on it shrouding wouldn't be much of an issue. :?:
Author:  james jaggers [ Sun Jan 14, 2007 11:24 pm ]
Post subject: 
We are very picky. We have been told before that air flow is not that important when being forced. Frankly I do not believe that. Dynos tell us that airflow is just as important with any kind of forced induction.
Author:  Tom Drake [ Mon Jan 15, 2007 4:56 am ]
Post subject: 
Quote:
We are very picky. We have been told before that air flow is not that important when being forced. Frankly I do not believe that. Dynos tell us that airflow is just as important with any kind of forced induction.
I have heard this same garbage spewed many times by people who should know better. I got tired of hearing "just turn the boost up!" Our turbo motors had responded to the same things a NA motor responds to but with greater results because the boost seems to magnify the effect. ESPECIALLY THE HEADWORK!

Trust me! :wink:

Tom
Author:  james jaggers [ Mon Jan 15, 2007 2:48 pm ]
Post subject:  more air flow figures coming with mods
We have went on and cut our angles in the seats. We have decided what valves to use. The valves were decided by figuring the biggest part of the bowl after being opened. That will be the restrictive part of the head. We will be posting some more numbers in a few days. It should improve a considerable amount over the original numbers. When we get are best air flow at its best lift than I can call Gordon at Comp cams and order me a roller to my specs. Remember a natuarally aspirated engine cam is totally different than a turbo cam. The best cam for a turbo is a early 70's stock cam. There are probably some better but for the money it is hard to beat a stock cam. I have chosen to use a roller cam and lifters or I would use a stock cam.
Author:  james jaggers [ Mon Jan 15, 2007 2:49 pm ]
Post subject:  looking for more flow
I hope we can reach are target airflow. I have seen some as high as 240's posted on the internet, but that is hard to beleive, that would be a 100 cfm increase. Is there anyone out there that has witnessed that kind of air flow on a slant six head first hand, on a calibrated machine?
Author:  sandy in BC [ Mon Jan 15, 2007 3:09 pm ]
Post subject: 
Good luck with Comp and a roller cam.....

You can use a larger ex v/v than 1.45 by relieving the chamber around the valves. It is simple and effective. I used a 1.50 sbc valve and ended up with plenty of room around the valve. By leaving the head deck unmilled(cept to clean up) and milling the block for compression you can avoid bore notching and block mods.

I used info from Panic's site to do the chamber work...good math

http://victorylibrary.com/mopar/chamber-tech-c.htm
Author:  james jaggers [ Mon Jan 15, 2007 4:29 pm ]
Post subject:  exhaust valve
Yea, we used a small chevy and od'd it down to 1.455 plus deshrouded th head.
Author:  Dart270 [ Mon Jan 15, 2007 7:05 pm ]
Post subject: 
Those stock #s are in line with what I have seen on flow benches at 28".

230CFM is the biggest I've heard of, and from a reliable source. 240 would be as yet unheard of. You will be doing very well if you can get to 210-220 in only one or a few tries.

Happy hogging!

Lou
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