flow figs

[Moparmal]

Recently I got my cast 587 heads upgraded to 2.02 valves. I thought some might be interested in the comparison flow figs.

Heads: 587 , mildly ported, 3 angle valve job

I have no exact details on what was done when they were ported - but it was a fairly conservative approach done by a pro.

Previously, they were running 1.94 tulip valves.
Now, they've been fitted with 2.02 Nailhead backcut valves.

So these figures reflect a valve change only - no extra port work or seat work has been done.

- Same bench, at 28".

1.96
200/138
300/176
350/190
400/200
450/212
500/228
550/234

2.02
200/? (Can't read his writing!)
300/170
350/195
400/219
450/231
500/240
.550/243

Im pretty happy with the improvement, especially at mid-high lifts.

One opinion says that they could have benefitted from a little more off the roof, as they started to stall after .550...but I didn't want a "full house" job anyway.

So anyone considering a mild port job to 360 cast heads, there seems to be some value in using nailhead valves.

 

[BJR Racing]

Mal,
I just finished the heads for 72scamp_swinger and will be putting these on his engine today. The heads are 915 J so I take this into account of maybe a better port shape. But this is what they flowed just a minute ago with 1.88/1.60 valves and a gasket match and bowl blending on the intake side and just a bowl blend on the exh. side, with a good VJ.

Lift........Int..........Exh
.100.......97...........92
.200......167.........142
.300......207.........170
.400......226.........198
.500......232.........201
.600......232.........204

 

[rumblefish360]

Those heads for 72scamp_swinger are going to be able to produce some really nice power for a great street machine.

 

[1wild&crazyguy]

Good stuff mal,
I like the sb iron and yes a nail head can work very well.

Are these the 3/8 or 11/32 stem diameter?


Bobby, I gotta be honest...
what's your point? He's talking head diameter flow difference and stem size/style and you post 'look at my numbers with smaller valves, there bigger'
I guess if it was me I kinda take it like''you're guy sucks at porting, you got ripped and can't do a valve job''
comparing the #'s of 2 different porters? who specializes in mopar?
It just sounds funny reading it.imo

I guess it wouldn't seem that way if maybe it read like..
''yeah Iron heads have a lot of potential and after working with them many years I have found and come with key practices in which I'm able to gain really big #'s through the entire range with even small valves''.

Heck maybe a ''good for you''??

Not trying to start anything, it just took me back a lil when I read it cause I usually only see this kind of post in rebuttel to someone saying iron don't flow for squat.

 

[moper]

Mal, that's typical for them. The lower lift flow usually can be boosted a bit by the initial bowl and valve job work. Something to consider is the port may be bigger than it should be, which means the air slows at low lift with a nailhead that doesn't help turn the air at low lift as well. hat might be cool (and this is just free thinking here...) would be to stick in tulip 2.02s with a 30° back cut and see that the numbers do. I'd wager they pick up at low lift and stay the same above .350". Also, benches vary day to day, operator to operator. So unless they were tested by the same guy, on the same day, with the same weather around, it's easy to get numbers that vary as much as 10cfm.

 

[1wild&crazyguy]

Thats true moper, the weather changes, operator, bench all change the #'s.
I think the tulip/nail head debate outcome really depends on the how the short turn is done or how far it was laid back to an extent.jmo

 

[rumblefish360]

Ah, I think you just took it wrong. That aint Bobby. He's just showing what he's got for a customer.

1.96............1.88.......2.02 int. valve sizes
200/138........167.......???
300/176........207.......170
350/190........___.......195
400/200........226 ......219
450/212........___ ......231
500/228........232.......240
550/234........___.......243

Like Bobby thinks, the J may be a bit better head to start with in his opinion, here you can see his low lift numbers are a bit better and within a few CFM up top.

The main thing is Mal showing what a valve change can do and the gain by it, (Which is good) the pro's and con's can be debated, the best useage in manyways can be talked about, but it is all moot as a bench racing discussion, which is good and healthy.

 

[moper]

1Wild, Rumble, that's where I was going. If I recall right Bobby prefers the tulip design valves. I hope I am not putting words in his mouth.. correct me if I'm wrong Bobby . I think if the initial port work is done knowing nailheads are going in it, the low lift won't be compromised. I tend to make a bowl smaller if I know nailheads are going in. I'll leave a bit more of a venturi below the seat and i don't do as much with the short side radius of guide boss if I'm running nailheads. Part of the "smaller is better" thought process.

Sorry, had to edit that. I typed slower than I was thinking.

 

[rumblefish360]

Being I didn't get a chance to edit my post for a 3rd time....He he he he

In addition to what Moper was saying, yes! Flow figures be damed to a point....like discussed above.
It's really about getting the gains your looking for in the area you need for what your doing with the engine and car.

A flow bench is a great tool....one day I hope to understand them on a personnal level... but I do know the percentage is better than actual figures when comparing one head against another by 2 different porters and operators an ocean apart.

OR stated another way, kind of, it's not cylinder head bench racing but what you gain and how well it's used for you.

Flow gain in a percentage for is a good was to show what you did as well. Mopar did it in the performance catolog with there heads and advertisements for them.

S/B head ported to a gain of 44% on the intake for ...yak yak yak..

This big block head flows XX% better as cast and in this ported head XX% more over the base head as cast and Yak yak yak

If you know where you start,.......and end...... your getting somewhere I think.

 

[perfacar]

hi, I notice one figure missing from all this flow testing! port velocity!! as mr betts of super flow stated, don't get hung up on big numbers, port velocity and port shape are everything!! velocity is what fill the cylinder!! just food for thought. I converted your high numbers back to 25 ", 234 =221, 232 =219, 243 = 229. the later super flow benches are set at 25" test pressure.

 

[BJR Racing]

1wild,
Sorry you took it wrong, as I didn't intend to have it come across like that. But more about the differences in the castings and a intermidiate valve size. I sure didn't want it to come across as who's better or anything like that. That surely isn't and wasn't my intent.


I guess I should delete the post if it offends anyone.

 

[1wild&crazyguy]

1wild,
Sorry you took it wrong, as I didn't intend to have it come across like that. But more about the differences in the castings and a intermidiate valve size. I sure didn't want it to come across as who's better or anything like that. That surely isn't and wasn't my intent.


I guess I should delete the post if it offends anyone.

It aint like that, no need to delete cause someone is/was offended, especially since you just made the real intention known.

 

[Moparmal]

Lift........Int..........Exh
.100.......97...........92
.200......167.........142
.300......207.........170
.400......226.........198
.500......232.........201
.600......232.........204

vs

2.02s

300/170
350/195
400/219
450/231
500/240
.550/243

No issue with this 1 Wild - Its a worthwhile comparison -

They are Cheb stem diameter.

Bobby - Its interesting how the 1.88s flowed so much better at 300 lift, yet by 450 they were dropping off and out of the running at 500.

Why would you say this was? - Was it just down to valve size or would the "type" of valve play a role as well?

(I'm kind of assuming the J head port shape would equal any bit more porting on the 587s - as the 587s are not really "hogged out"?)

Perfacar - I also appreciate velocity is important - however these are going on a 4" stroke SB, so the pistons will be really sucking ......

 

[BJR Racing]

Mal,
I built the heads for a given cam being used and that the engine needed all the flow that it could get below the curve. The heads are a bit large for a street/strip engine, and a smaller better set of heads would have made 30-40 more HP. But I had to use what I was given to work with. I tried to keep the port as small as possiable too. The heads cc'd out at 153 cc's intake port and 65 cc chambers and 70 cc exhaust ports as finished. Had the cam been larger I could have ported the heads differently and made it pull up higher, but being this engine is only a 318 .030 and the cam is a .520/.540 lift with 244/252 @ .050. I had to make the low lift air flow as strong as possiable, for the head and valve size being used.

 

[Moparmal]

Malo,
The heads are a bit large for a street/strip engine, and a smaller better set of heads would have made 30-40 more HP. .

Can you explain "large" - chamber size or runner size?

and the cam is a .520/.540 lift with 244/252 @ .050. I had to make the low lift air flow as strong as possiable, for the head and valve size being used

Sounds like the same cam Im using- Comp XS282S ?

I tried to keep the port as small as possiable too.

For velocity?

So in a nutshell, its a trade off between velocity or high#s flow with a small cube engine?

Are Eddies or EQs any easier to get good high lift #s and keep velocity?

 

[moper]

I'm trying to think of an analogy for flow benches and the numbers they spit out... I guess they are like using someone elses burnout marks to shop for tires for your car. Some guys can do a hell of a burnout but the tries really are not good. Some guys can't leave a mark but the car launches like a Pro Stock. You really can't tell until they are on your wheels on your car, on your pavement. Benches are just tools, and the numbers do not directly translate into anything more than to indicate the direction the power level MIGHT go. Remember, that figure for say, .500 or .550 lift... The time the cam is in that area is very short in terms of the whole lift cycle in relation to the flow trends at .200 lift. So you really want to make sure that if your port trends to lose flow at low lift you get a lot at higher lifts. Low lift is where the valve is open for the longest, but mid lift is where the port velocity is catching up to the valve's motion. High lift is where the velocity can get too fast and the port chokes of the fuel comes out of suspension. All these numbers point to trends only. Exact numbers are imposible to complare and almost irrelevant. It's the trends that matter.

 

[Moparmal]

Moper - which is why one set of heads might suit one combo better than another - and why BJR ported the heads in this thread for low lift flow - yes?

 

[BJR Racing]

Mal,
The runners were 153 cc's which is a bit large for a 318 .030 and a 3.94 bore. The engine would work better with a 135 cc runner, and a smaller intake valve to help the port velocity better. The larger the runner the lazier the air flow becomes, then add a large intake valve and well low lift flows become real laxed. For instance a Pro Stock head doesn't really start to flow anything until .400 lift then it's off to the races. It's due to large ports and large valves. Thats why they turn the rpm's up before they leave, to get the velocity working in the heads.

So yes your right I had to get the best results for the heads that I was working with, and keep the port volume small so it wouldn't hurt the velocity too much. Thats why I used the 1.88 tulip valves to, as this helps to close up the port volume some and still make good flow #'s.

 

[daredevil]

Mal,
I just finished the heads for 72scamp_swinger and will be putting these on his engine today. The heads are 915 J so I take this into account of maybe a better port shape. But this is what they flowed just a minute ago with 1.88/1.60 valves and a gasket match and bowl blending on the intake side and just a bowl blend on the exh. side, with a good VJ.

Lift........Int..........Exh
.100.......97...........92
.200......167.........142
.300......207.........170
.400......226.........198
.500......232.........201
.600......232.........204

at how many inches?

 

[toolmanmike]

Interesting post! Thanks to all. toolmanmike

 

[Moparmal]

Still got one question -

Are Eddies or EQs any easier to get good high lift #s and keep velocity?

MM

 

[BJR Racing]

at how many inches?

28"

 

[BJR Racing]

Still got one question -

MM

I've not had the EQ's in my hands yet but have had the Eddy's. Yes they are easier to get high lift flows from but you have to have a cam that large and most don't get over .650 lift even in the roller grinds, unless it's a special custom grind. But then you'll need longer valves and valvetrain parts to correct all the problems that this causes.

Eddy's flow well at .600 and .700 lift but this is a area that is rarely seen. So look at the .500 and .550 #'s and less and see if the heads are as good as most LA small block heads. What I've found is that they are very similar when ported. And sometimes the iron was better. Thats why I don't spend any $$$$ on aluminum heads unless they are or have real good low lift flow #'s and in relation to port size, and valve size. I can't see spending $1,300 or more for a set of heads that only work as good as the stock irons I already have, then spend more to get them to work properly. When your going to spend the same $$$ for doing the irons the same way. Some how 40 lbs. doesn't make that much difference to me.

 

[daredevil]

28"

ok apples to apples

 

[1wild&crazyguy]

Saying bigger ports are lazier really depends upon the cubes underneath.

Like w2's on a 318 or w2's on 425 stroker.

Prostock needs airflow for hp there making but also require more port volume for the cubes vs rpm it takes to make that power with the cams they use, 4000 or so is where the power band starts.

The smaller the better but only to an extent.

I had my head flowed at 28 for while, now I go somewhere else and flow them @10 inches depression and convert.
All the guy's I know running 7's in the 1/4 flow there heads @ this depression, they say more accurate.