318 head flow

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skrews said:
When we did the 3 way 1020 bench comparo, I made a fixed radius plate out of high density particle board with the radius cut in with a router. The funny thing was that the fixed radius plate flowed worse than any of the clay adapters.

/QUOTE]

I have witnessed that many times. In fact I machine a plastic radius plate when it is a serious effort. Everytime it flows less with the plate as opposed to a hand formed clay radius. J.Rob
Click to expand...
 
PRH said:
If it’s a true “flow bench comparo”, then everything needs to be the same....... bore size, radius inlet, ex tube if used.

Otherwise you’re comparing the “flow bench service” as opposed to the bench itself.

I bought 5 PTS test plates to be sure I can keep tabs on how mine is working.
100, 200, 300, 350, 400.
Click to expand...
PRH said:
If it’s a true “flow bench comparo”, then everything needs to be the same....... bore size, radius inlet, ex tube if used.

Otherwise you’re comparing the “flow bench service” as opposed to the bench itself.

I bought 5 PTS test plates to be sure I can keep tabs on how mine is working.
100, 200, 300, 350, 400.
Click to expand...

We did this on Speedtalk way back. I was sent 2 heads and flowsheets, and radius plates, plastic, and of course valves, springs, retainers, etc. I thought it was awesome as I am a stickler for accuracy. Learned my flowbench is a heartbreaker and I love it. J.Rob
 
skrews said:
When we did the 3 way 1020 bench comparo, I made a fixed radius plate out of high density particle board with the radius cut in with a router. The funny thing was that the fixed radius plate flowed worse than any of the clay adapters.
Click to expand...
How much flat face area around the radius entry? Try the same width around as clay...better yet flow it with the intake being used to get a bigger picture...add the carb.lol
 
Gunna try of set of these bad boys

lightened-engine-valves.jpg
 
It seems that SF-1020’s generally show lower numbers than the 600’s.

I don’t really care if mine is a heartbreaker or not, as long as the numbers are at least “reasonable”.

I think my bench is fairly middle-of-the-road for what the numbers are.
Once in a while my numbers are slightly higher, sometimes really close, and sometimes(well, most times) a bit lower.

Two heads I tested recently that came with flow data ...... my numbers were about 5 higher on the intake side of one head, and on another set of “big” aftermarket Pontiac heads my numbers were 10-15 lower.
 
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LIFT-------AS CAST------PORTED

.100”-----51.8/N/A--------71.8/N/A
.200”-----92.5/70.7--------148.4/86.3
.300”-----130.1/104.3-----212.2/113.9
.400”-----163.9/113.2-----241.5/131.1
.450”-----169.1/115.2-----244.6/137.7
.500”-----170.4/117.3-----246.7/139.7
.550”-----172.2/119.0-----242.6/144.9
.600”-----172.5/120.4-----240.8/144.9

All #’s at 28” of water
No flow tube on exhaust
As cast #’s are 1.78”/1.50” valves, Ported is with 2.02”/1.60” Ferrea 5000 Series, No Back Cut.
Ported Intake Runner Volume is 151 CC’s

For more information on “302” Swirl port heads email [email protected]
 
dirty white boy said:
LIFT-------AS CAST------PORTED

.100”-----51.8/N/A--------71.8/N/A
.200”-----92.5/70.7--------148.4/86.3
.300”-----130.1/104.3-----212.2/113.9
.400”-----163.9/113.2-----241.5/131.1
.450”-----169.1/115.2-----244.6/137.7
.500”-----170.4/117.3-----246.7/139.7
.550”-----172.2/119.0-----242.6/144.9
.600”-----172.5/120.4-----240.8/144.9

All #’s at 28” of water
No flow tube on exhaust
As cast #’s are 1.78”/1.50” valves, Ported is with 2.02”/1.60” Ferrea 5000 Series, No Back Cut.
Ported Intake Runner Volume is 151 CC’s

For more information on “302” Swirl port heads email [email protected]
Click to expand...
Should have just used a magnum head for that port volume and flow.
1.88 yielding 220@137cc , shady geta 27cfm for another 14cc increase. Make anything bigger, keep the same shape, it will flow more. How much digging you wanna spend time doing for a generally weak outcome is the question.
 
MOPAROFFICIAL said:
.100”-----51.8/N/A--------71.8/N/A
.200”-----92.5/70.7--------148.4/86.3
.300”-----130.1/104.3-----212.2/113.9
.400”-----163.9/113.2-----241.5/131.1
.450”-----169.1/115.2-----244.6/137.7
.500”-----170.4/117.3-----246.7/139.7
.550”-----172.2/119.0-----242.6/144.9
.600”-----172.5/120.4-----240.8/144.9

All #’s at 28” of water
No flow tube on exhaust
As cast #’s are 1.78”/1.50” valves, Ported is with 2.02”/1.60” Ferrea 5000 Series, No Back Cut.
Ported Intake Runner Volume is 151 CC’s

For more information on “302” Swirl port heads email [email protected]
Click to expand...

^^^^^^^LOL. J.Rob
 
PRH said:
That’s closer than a lot of stuff I see.

If I tested a head that was advertised at 350, and it was 342 on my bench...... I’d call that pretty close.
I figure if nothing else, it’s a different radius plate being used.

I had a CNC ported head here that flowed about 50cfm less than advertised.
Yet, I’ve tested other cnc ported heads from that same supplier that flowed very close to the advertised numbers.

However, overall I see what I consider are fairly noteworthy differences often enough so that if I really want to know how it compares to other stuff I’ve tested....... I know I’m going to have to test it myself.
Click to expand...

In my experience to see 50 cfm less than advertised is fairly common, in some cases I have seen 80 cfm less than advertised. The upside to my testing is I don't scratch my head as much when the dyno "lines up" with the flowbench. J.Rob
 
dirty white boy said:
LIFT-------AS CAST------PORTED

.100”-----51.8/N/A--------71.8/N/A
.200”-----92.5/70.7--------148.4/86.3
.300”-----130.1/104.3-----212.2/113.9
.400”-----163.9/113.2-----241.5/131.1
.450”-----169.1/115.2-----244.6/137.7
.500”-----170.4/117.3-----246.7/139.7
.550”-----172.2/119.0-----242.6/144.9
.600”-----172.5/120.4-----240.8/144.9

All #’s at 28” of water
No flow tube on exhaust
As cast #’s are 1.78”/1.50” valves, Ported is with 2.02”/1.60” Ferrea 5000 Series, No Back Cut.
Ported Intake Runner Volume is 151 CC’s

For more information on “302” Swirl port heads email [email protected]
Click to expand...

Probably water leaking paper weights.
 
MOPAROFFICIAL said:
Thanks for sharing the lesser path.


273 closed chamber, 310 casting,1.78 valve
Ported. 1.78 int
.100..59
.200..122
.300..175
.400..200
.450..202
.500..200
.600..205
Final port volume..135cc, chamber 66.5

Un ported.. 124cc port volume 1.78 int
.100..51
.200..107
.300..154
.400..159
.500..165
.600..166

Just more grains of salt...
Click to expand...
Moparofficial,
Please tell me what are 310 castings. I don't see that # on my list.
Thanks, Richard
 
If I stumble across some 318 heads, I may pick them up and fiddle with a couple of ports out of curiosity.
I’d like to see just how hard I’d have to work to get near 205–210.

More work than I’d like to do I’m sure.

The most lopsided pair of heads I recall testing were some 2.02 J heads, which were originally 1.88 heads.
They came to me just for freshening, and were really in good shape overall.
He wanted them flowed “just to see”.
I tested a couple ports on one head and was pretty surprised how good it was...... like 215, with nailhead valves but zero porting.
I was checking angles, etc...... and was figuring the shop that did them really knew some “trick” to get them to be that good.
Curiosity got the best of me, so I tested a couple ports on the other head.......195cfm.
Aaaahhh, okay....... the 215 head was just one of those freakishly good castings.

In stock form they were pretty far apart, but I suspect if they both got the same level of rework, say..... shooting for 235-240cfm....... that 20cfm difference between the heads would have all but disappeared.
 
Just to drag this back from the dead here are some flow #s off an untouched 308 casting stock valves 1.88/1.6 vs the ported 675s 1.94/1.6
.......308int....675int....308exh....675exh
.100......54........63..........45...........45 +16/+0
.150......80.......109.........70...........74 +29/+4
.200.....117......142.........87...........97 +25/+10
.250.....150......163........108.........120 +13/+12
.300.....164......191........126.........136 +27/+10
.350.....183......202........139.........146 +19/+7
.400.....195......205........150.........154 +10/+4
.450.....205......192........159.........158 -13/-1
.500.....207......192........162.........160 -15/-2
 
Nice 308 head with factory valve and valve job(valve seat not beat up or sunk):
4.00 bore, 3/4” radius plate:

A- stock head and valve/valve job
B- grind/narrow seat, back cut valve, minor bowl blend

Intake:
Lift———A/B
.100— 51.6/ 58.8
.150— 75.2/ 90.0
.200—107.9/127.0
.250—137.1/157.4
.300—163.0/183.3
.350—180.8/199.3
.400—192.2/206.2
.450—201.9/208.2
.500—206.2/209.5
.550—207.5/210.8
.600—207.1/210.0

Exhaust:
Lift———A/B
.100— 42.7/ 62.6
.150— 67.5/ 87.4
.200— 89.9/106.0
.250—110.9/130.2
.300—127.7/143.1
.350—139.8/152.2
.400—147.5/157.3
.450—150.9/161.2
.500—153.5/163.0
.550—154.8/164.3
.600—155.3/164.3

Sure........ compared to the previous post, it’s a different head, on a different bench, with a different radius entry.
Compare at your own risk !!
 
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PRH said:
Sure........ compared to the previous post, it’s a different head, on a different bench, with a different radius entry.
Compare at your own risk !!
Click to expand...

From an experienced eye, there close enough to call the same. Variations from port to port & very other little things that effect the machines readings that show up aren’t a big deal unless there is a noteable difference in flow on the same exact head.

When I see a fully ported head flow 20+ cfm different on another bench, then I wonder WTF is going on.

I realize there a lot of things that can effect the read out from lack of coffee to less than credible porters trying to upsell there head.
 
PRH said:
Nice 308 head with factory valve and valve job(valve seat not beat up or sunk):
4.00 bore, 3/4” radius plate:

A- stock head and valve/valve job
B- grind/narrow seat, back cut valve, minor bowl blend

Lift———A/B
.100— 51.6/ 58.8
.150— 75.2/ 90.0
.200—107.9/127.0
.250—137.1/157.4
.300—163.0/183.3
.350—180.8/199.3
.400—192.2/206.2
.450—201.9/208.2
.500—206.2/209.5
.550—207.5/210.8
.600—207.1/210.0


Sure........ compared to the previous post, it’s a different head, on a different bench, with a different radius entry.
Compare at your own risk !!
Click to expand...

A 20cfm gain through the bulk of the lift curve, nice gains for minimal easy work. The benefits of a good valve job and valves are often overlooked.

The differences in our 308 flow tests for the reasons you mention, drive home the point I try to tell people all the time.
 
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skrews said:
A 20cfm gain through the bulk of the lift curve, nice gains for minimal easy work. The benefits of a good valve job and valves are often overlooked.
Click to expand...

The other thread with the dead and buried valve job 308's, could have gotten there in a 1/4 of the time and better low if it had a good valve job to start.
 
The differences in our 308 flow tests for the reasons you mention, drive home the point I try to tell people all the time.
Click to expand...

Frankly, IMO those are close enough to where they could be two ports off the same head.
 
Ain't gonna lie at the time I did that test (probably 10 years ago) I cherry picked the best looking intake port to test. In retrospect I should have tested a couple of other ports for an average.
 
As a comparison as to how much better the stock 308 head is compared to a 587 head.....
This was a nice low use 587 head, fresh 3 angle valve job, 1.88/1.60 tulip(stock) style SS valves with a back cut(no blending):

Lift———in/ex
.100— 60.0/ 53.5
.200—122.8/102.4
.300—176.8/129.3
.350—186.4/135.4
.400—188.4/139.0
.450—190.8/142.0
.500—192.0/143.2
.550—193.2/144.4
.600—193.6/145.6

An X head that isn’t beat to death, and isn’t plagued with some serious core shift, with a valve job and some 2.02/1.60 nail head valves can flow in the [email protected] range with no porting on the intake side.
Unfortunately, the ex ports aren’t any better than other lowly 360 heads....... sometimes not even reaching 140cfm in stock form.
 
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