Flow numbers for 2.4 head

[Spilner521]

Over on J-body.org, a guy finally flow benched a stock 2.4 head, ported it, and then flow benched it again. Another guy, for comparison's sake, posted numbers from a stock and ported 086 head.

For those that think an untouched, stock 086 head is the end all, best decision for a performance head, you may be mistaken.

Here are the results:


Stock 2.4 Head ------Stock 086 Head ---Ported 2.4 Head ----Ported 086 Head
Intake:
.100 lift 90.3 cfm ----73.3 cfm ----------107 cfm ------------84.2 cfm
.200 lift 155.9 cfm ---149.2 cfm ---------162 cfm ------------164.8 cfm
.300 lift 217.7 cfm ---221.7 cfm ---------224 cfm ------------226.7 cfm
.400 lift 258.9 cfm ---267.0 cfm ---------268 cfm ------------269.3 cfm
.500 lift 277.9 cfm ----------------------282 cfm----------------------
Exhaust:
.100 lift 81.2 cfm ----57.1 cfm ----------79.65 cfm ----------131.4 cfm
.200 lift 119.5 cfm ---125.1 cfm ---------140.1 cfm ----------139.7 cfm
.300 lift 126.0 cfm ---167.7 cfm ---------173.3 cfm ----------181.6 cfm
.400 lift 129.2 cfm ---180.3 cfm ---------180.0 cfm ----------202.5 cfm
.500 lift 135.5 cfm ---205.6 cfm ---------183.0 cfm ----------237.3 cfm

As you can see, contrary to what some have stated, the ported 2.4 head will outflow a stock 086 head until .5" of lift. As to be expected, a ported 086 will outflow the ported 2.4, but even then it's not by much, with the greatest differences only on the exhaust side.

Now we can stop speculating and use actual numbers to base decisions off of.

[Oldsman]

well if you look at it closely and base it off .400 lift the stock 2.3 head does flow as good as a ported 2.4 head. so your attempt of making some of us look like an ass has failed. i have always said the stock 086 will flow as good as a ported 2.4 head. and you have proven it.

But to be objective about this..............who polished and ported the head? was it the same guy that did both heads? Does he truely know what he is doing? how many years of experience does he have at polishing&porting heads for all out applications? Were they cnc ported?

Polishing and porting a head is a skill that only some who has years of experience can do properly and get the max performance and flow out of head.

[Spilner521]

Just to be clear, I was in no way trying to make anyone look like an ass. I'm not pointing fingers at anybody. I just know there has been talk in the past about how a stock 086 head will out flow a ported 2.4 head. These numbers show that this is not exactly the case.

Yes, the 086 will flow as well as the ported 2.4, but not until .400 of lift. Not many aftermarket cams that are going into these heads are higher than .400 lift. So up until high lift, the ported 2.4 does slightly outflow the stock 086. This, in my opinion, would make it easier to get the 2.4 head ported as opposed to dealing with the high compression issues of swapping to the 086. Some people, who may have wanted to swap to the 086, may change their mind after learning this info. Others may still want to swap heads, and that's their choice. I'm only putting the information out there so they can see the numbers and decide on their own.

The guy that did the porting is a college student and I believe he was using tools and a flow bench from one of his classes. He flow tested his head, then ported it, and flow tested again on the same bench. I have no doubt that someone who has been porting heads for years and knows exactly what they're doing will do a better job leading to greater flow numbers.

[Oldsman]

point taken. but if you go with HO or W-41 cams then you are at .410 lft and they are available. I have seen cams with .475 lift. but obviously these are more for a all out N/A combination and in that case an 086 polish and port will fit the combination better.

When it comes to the head selection and cam selection you can NOT just trow parts together you must figure out your combination and what would work best. But anyone who knows a damn thing about building a motor for some real hp knows this.

But just one thing that has got under my skin with the whole 086 head discussion.............the high compression issue. that the only way to resolve it is by thicker head gasket or there is no way around it.

Has anyone actually built motors? Anyone actually know a damn thing? the reason for the high compression is the size of the combustion chamber. Now if someone really wanted to do the 086 head and drop the compression for boost they might want to actually do some reading from some engine builders. And spend the cash. And it has nothing to do with head work or a damn head gasket.

[DOHC_tuner]

Lower compression pistons?

[Spilner521]

Originally Posted by Oldsman

the reason for the high compression is the size of the combustion chamber.

This I know. I never mentioned using a thicker head gasket, but I know others have. I would discourage it actually to anyone asking about it.

[Spilner521]

Originally Posted by DOHC_tuner

Lower compression pistons?

Custom made lower compression pistons.

...unless you're going all out on an all motor setup.

[Oldsman]

Originally Posted by Spilner521

This I know. I never mentioned using a thicker head gasket, but I know others have. I would discourage it actually to anyone asking about it.

right a thicker gasket screws with chain tension and crap

[Oldsman]

Originally Posted by DOHC_tuner

Lower compression pistons?

by the ? i take it you aren't sure and should do some reading

[spyhunter]

what's lower compression pistons?

[NoSweat83]

Originally Posted by spyhunter

what's lower compression pistons?

[DOHC_tuner]

i was being sarcastic

[spyhunter]

liar!

[rustyballs_69]

Originally Posted by Oldsman

And it has nothing to do with head work or a damn head gasket.

The compression?

[Spilner521]

Originally Posted by rustyballs_69

The compression?

The high compression resulting from putting the 086 head onto the 2.4 block, yes.