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chev vs ford?

2K views 8 replies 5 participants last post by  Ohio XB 
#1 ·
hey, i don't know if this has an effect but i figure i'll get your oppinions anyways...

i've noticed that the chev (and old holden) inlet port arangement results in slightly more equal length runners than the ford design when used with single carby manifolds. It seems that the difference is very slight but i'm wondering what sort of effects this would have if any on sonic or inertia tuning and also air flow rates. I think it would be possible to correct air flow rates with runer sizes but that still leaves the question of pulse tuning?

I've noticed that some of the edelbrock victor manifolds have a plenum that is very rectangular, almost like a tunnel ram with only one carby on top, is this to equalise runner lengths?

It seems to me that the unequal lenght runners on most clevo manifolds don't hurt them at all so it probably doesnt matter...
 

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#2 ·
gasxd said:
hey, i don't know if this has an effect but i figure i'll get your oppinions anyways...

i've noticed that the chev (and old holden) inlet port arangement results in slightly more equal length runners than the ford design when used with single carby manifolds. It seems that the difference is very slight but i'm wondering what sort of effects this would have if any on sonic or inertia tuning and also air flow rates. I think it would be possible to correct air flow rates with runer sizes but that still leaves the question of pulse tuning?

I've noticed that some of the edelbrock victor manifolds have a plenum that is very rectangular, almost like a tunnel ram with only one carby on top, is this to equalise runner lengths?

It seems to me that the unequal lenght runners on most clevo manifolds don't hurt them at all so it probably doesnt matter...
It's to do with the order of the inlet and exhaust valves. Ford alternates between Inlet and Exhaust where the SBC and 308 are like this: IEIEEIEI

If you look at the exhaust on the sbc & 308's you will see the inner two outlets are right next to each other were as on the ford motors the outlets are evenly spaced.
 
#3 ·
xbgs351 said:
It's to do with the order of the inlet and exhaust valves. Ford alternates between Inlet and Exhaust where the SBC and 308 are like this: IEIEEIEI

If you look at the exhaust on the sbc & 308's you will see the inner two outlets are right next to each other were as on the ford motors the outlets are evenly spaced.
Chev have gone the Ford way with alternating inlet/Exhaust on their latest top end race engines and LS1/2 Gen3/4 engines.
The chev/holden siamesed port configuration is largely obsolete now.
 
#4 ·
It also depends what other manifold you are comparing the one in the pic to. That one is a top end horsepower intake that would not do very well on the street. You can get a manifold of similar appearance for a Ford, but again not practical for a street.

Are you comparing this intake to a dual plane? Got a pic of the one you were comparing it to?


Steve
 
#5 ·
a person whom i have a very high mechanical regard for (read: built/raced nitro hemis) has looked at my TFC clevo manifold and is VERY impressed with the port/runner/plenum design... with the 4V alloy heads i'd say the chevy boys don't have the margin on us as they think :)
 
#6 ·
im talking about the fact that two adjacent cylinders have a more similar path towards the center of the manifold in the chevy design regardless of what single carby manifold you use. this obviously goes out the window with multiple carbs or injection.

i was listing the example to show that with the ford design you need a larger plenum to achieve reasonlably equal runner lengths while the chevy design allows for easy, equal runner lengths.

i am comparing two manifolds which strive for maximum, even flow and power from a single carby.
 

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#9 ·
Ah, I see what you mean. Yes, the Chevy intake would have a slight advantage, but once the flow gets to the cylinder head the next factor comes into play. I am not real familiar with Chevy heads but the intake alone will not win the race. Once the flow gets to the head the head design of the Ford could make up for the lack of intake design. Also cylinder heads are responsible for producing much more power than intake manifolds so I wouldn't sweat any advantage the Chevy has in intake manifold design. ;)


Steve
 
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