Olds batten heads

[rocketracer380]

Stage 2 batten olds head flow numbers stock as they came from batten with push rod sleeves 2.10 in 1.6 ex any one have flow data on these heads

[Walter R. Malik]

Stage 2 batten olds head flow numbers stock as they came from batten with push rod sleeves 2.10 in 1.6 ex any one have flow data on these heads

4.125" Bore size; #3 or #6 port
2.19" intake valve - 1.680" exhaust valve
as received valve job
with a "clean-up" bowl port only.

Lift ..... int ..... exh. (no tube)
.100 .... 75.8 ..., 69.8
.200 ....142.4 ... 117.9
.300 ....207.1 ... 158.0
.400 ....255.7 ... 180.7
.500 ....286.1 ... 193.8
.600 ....315.0 ... 202.2
.700 ....331.6 ... 206.5
.750 ....338.7 ... 209.6

[mag2555]

Pretty soft on the exh numbers !

There only showing a 62% ratio @ .700” lift, at least its 68% at .500” lift!

[maxracesoftware]

Pretty soft on the exh numbers !

There only showing a 62% ratio @ .700” lift, at least its 68% at .500” lift!

i also have Flow Numbers for those Heads
but they are on a hand written Flow Sheet ... did not have a Computer hooked up to my Flowbench back then ???

i will search thru the 4 containers for them ... will Post when i find that Sheet

[hoffman900]

Pretty soft on the exh numbers !

There only showing a 62% ratio @ .700” lift, at least its 68% at .500” lift!

I’m not sure you can discuss the efficacy of the exhaust port on cfm alone...

[mag2555]

True,since we are not factoring any reductions they may be on the inlet side due to whatever intake manifold may be used, and on the exh side we have the motors compression ratio that has a effect also, but all of that still does not negate the flow ratio starting point that I posted about.

If you choose to average those flow numbers things look even worse, you end up with only a 57.9% ratio, and if you care to then give some more help and factor in the 4% added flow that a proper size header tube could add, you still end up with only a 60.2 % ratio.

[hoffman900]

Darin Morgan circa 2006

The 75% intake to exhaust flow ratio is NOT correct and never was. I think some engineer pulled this out of thin air.
The engines RPM range, size and intended use as well as other design criteria will be the deciding factor as to valve size and placement but trying to hit some preconceived flow ratio with total disregard for other more important tuning variables is not an intelligent or well thought out approach. I will admit that the industry is full of these little snippets of pseudo wisdom but one should not believe everything they hear. When you try and optimize the valve area in an unlimited engine combination you always sacrifice exhaust valve size for intake valve size. Its much easier to cam and manipulate the exhaust system to evacuate the cylinder ( dynamic blow down and cam shaft events) than it is to manipulate the intake tract. Current Pro Stock and Comp Eliminator engines have intake to exhaust (size in diameter) ratios of 70% and flow ratios of only 58% to a maximum of 61%. These engines are producing 2.78HP/CID at over 5800fpm piston speed so the that kind of shatters the long held belief that the exhaust should flow 75%-80% of the intake. Could we make more power if the exhaust flowed more. No, we tried that. Could we make more power if we increased the exhaust size and kept the same discharge coefficient? Yes it does but there isn't any room left for a larger valve because we just stuck this big intake in there so its really a mute piont. I know thats a simplistic explanation of what is going on but I think it drives the piont home.

[mag2555]

Thanks for posting that yet once again as you have in the passed , but that’s not the last word as you seem to lashed onto it as it is!

[hoffman900]

Thanks for posting that yet once again as you have in the passed , but that’s not the last word as you seem to lashed onto it as it is!

It isn’t, but the flow ratio could be fine or it might not be.

What is Port exit velocity, average port velocity, engine rpm goals, throat %, etc. ?

With what the op shared, one’s answer is simply “need more information”