318 head flow

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^^^ You are right on all accounts.
I have gotten 236 out of a lesser worked 360 head with 1.88 valve, and have hit low 280s with a "max effort" port job. You are also correct that the bowl is under sized, after a little probing with the sonic checker, they are as thin as I care to go. This whole 318 deal is just for ***** and giggles, science experiment is an accurate description though.
 
fishmens67 said:
You need a different bench. :)
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Why? So you can "feel" good about the numbers. I can assure you the engine won't care what any flowbench says. J.Rob

p.s. Why does it say MoparOfficial was the last post when there are none? Censorship?
 
The fact that the head is getting thin at only 205cfm makes me glad I never wasted much time messing with 318 heads.

The old Dulcich junkyard jewel 302 heads reportedly flowed 215 with 2.02 valves.

They got 400hp out of that thing, but I believe that was before the “discovery” that the barometer at Westech was pretty far off, and the correction was about 5% happy.
 
PRH said:
The fact that the head is getting thin at only 205cfm makes me glad I never wasted much time messing with 318 heads.

The old Dulcich junkyard jewel 302 heads reportedly flowed 215 with 2.02 valves.

They got 400hp out of that thing, but I believe that was before the “discovery” that the barometer at Westech was pretty far off, and the correction was about 5% happy.
Click to expand...

Those heads also cracked after a short time from what a read somewhere.
 
PRH said:
The fact that the head is getting thin at only 205cfm makes me glad I never wasted much time messing with 318 heads.

The old Dulcich junkyard jewel 302 heads reportedly flowed 215 with 2.02 valves.

They got 400hp out of that thing, but I believe that was before the “discovery” that the barometer at Westech was pretty far off, and the correction was about 5% happy.
Click to expand...

I asked Dulcich about that article and he told me the heads didn't make it off the dyno--water at the S.S. Aptly named J.J. lol
J.Rob
 
I think 1.88 / 1.6 is about as large a valve as I'd recommend putting in these castings. The cross section in these things just isn't going to allow larger valves to work to their potential anyway IMO. Thats why I used a valve and seat profile that favor low / mid lift numbers, because I was pretty sure there was no hope for big numbers at high lift.
 
Thanks for sharing the lesser path.


273 closed chamber, 315 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...
 
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Seems like every 273/318 head with a decent amount of work peaks around the same number. Steve Dulcich's heads 215, the set I worked on 205, the 310 castings you shared 205. My heads peak earlier do to the larger valve. These ports are a bottle neck, without significant work 210ish would seem to be the typical result. The motor I'm building these for has a 350 hp target so I'm pretty confident it'll get there.
 
RAMM said:
I asked Dulcich about that article and he told me the heads didn't make it off the dyno--water at the S.S. Aptly named J.J. lol
J.Rob
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Aaaahhhhh....... and now we know “the rest of the story”.
I wonder how many hours and dollars were wasted as a result of that article not providing that very relevant info.
 
^^^ Right lol. Hoping these turds of mine don't turn in to sprinklers. Fortunately the parts were all used junk I've had laying around for years, and my free time ain't worth ****.
 
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skrews said:
Seems like every 273/318 head with a decent amount of work peaks around the same number. Steve Dulcich's heads 215, the set I worked on 205, the 310 castings you shared 205. My heads peak earlier do to the larger valve. These ports are a bottle neck, without significant work 210ish would seem to be the typical result. The motor I'm building these for has a 350 hp target so I'm pretty confident it'll get there.
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When I did the 1.88 in them, the runner was the problem overall.
The numbers, i have downstairs, were peaking around 220cfm iirr. It wasn't max effort... but the amount material removed by hand was enough to scare you away from any max effort w/1.88 in a 318 124cc port.
In the end numbers looked like stock 360...only diff was instead of 160cc it was 137cc iirr.
 
Would be nice to have the same section chamber and set of ports to send around for a flow test, identical/same head... different benches.

I know it's been done before, speedtalk,yellowbullet folks have done this.
It would just be nice see how close they are with our own casting we use.
 
We've done that with the 1020 bench I use, and it gives lower numbers than the other 2 1020 benches tested. You'd be surprised at how much difference the clay radius can make. SF will also tell you that their 600 bench by design will give higher numbers than a 1020. The Sanez brand benches will give higher numbers than their SF counterparts.
 
skrews said:
We've done that with the 1020 bench I use, and it gives lower numbers than the other 2 1020 benches tested. You'd be surprised at how much difference the clay radius can make. SF will also tell you that their 600 bench by design will give higher numbers than a 1020. The Sanez brand benches will give higher numbers than their SF counterparts.
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Crazy stuff.
Makes the before and after very important to see what you're doing it for.
I use clay, its finger formed... and cheap.
If playing with runner/window size then you would have to develop a port ..say 3 ways/flow profiles, find that window dimension/s and then make radius plates for each to flow them.
 
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.
 
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.
 
Brzezinski fixtures on all 3 benches, same radius plate in all three tests. Did our best to keep it as close as possible.
 
8 cfm best to worst on BBC head that peaked in the 350 cfm range. Thats just a little over 2% variance, but it is a variance. Weather thats acceptable is debatable, but some people out there will get their underpants in a bunch over less.

IIRC the other 2 benches were within 2 or 3 of each other.
 
MOPAROFFICIAL said:
When I did the 1.88 in them, the runner was the problem overall.
The numbers, i have downstairs, were peaking around 220cfm iirr. It wasn't max effort... but the amount material removed by hand was enough to scare you away from any max effort w/1.88 in a 318 124cc port.
In the end numbers looked like stock 360...only diff was instead of 160cc it was 137cc iirr.
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I know some guys that have been experimenting with a stock stroke 318 and comparing it to a previous 318 with ported 360 heads. I think the difference in port volume has been an advantage in their current combination. Car is a full weight a body street car ,very mild hydraulic cam with a stock 904 converter and street gears (3.23), car is running consistent mid 12s at 107 -108mph.
 
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.
 
skrews said:
I think 1.88 / 1.6 is about as large a valve as I'd recommend putting in these castings. The cross section in these things just isn't going to allow larger valves to work to their potential anyway IMO. Thats why I used a valve and seat profile that favor low / mid lift numbers, because I was pretty sure there was no hope for big numbers at high lift.
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Same problem as the slanty head, there's enough "room" for much better & bigger valves, but casting inconsistencies make it impossible to do an entire head w/o taking a quick trip to watertown.
1.88's work great in a 3.50" bore, but doing a proper bowl deep enough to work at higher lifts is too risky. I cut some up and the "close" spots at the guide spot-face and short-side on some were scary before even starting the grinder!
 
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