Collector Size

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64physhy

64physhy

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Engine, 414 stroker, dynoed at 512hp and 525tq through a set of 1 3/4 hookers. I ran it for a while through a pair of Dougs and ran very consistent 7.17 @ 95mph in the 1/8, with a best 7.06 through a 2 1/2 x pipe exhaust with cutouts. 1.55 60'.

I installed some hooker 5303 1 7/8 headers, but haven't ran it yet or installed an exhaust. The collectors are slip on 3", and I have been trying to figure out if I should put 3.5" collectors on. I don't plan on doing an x pipe, just straight duals through race mufflers dumping in front of the axle through turn downs. Should I go with:
3" collectors to 3" pipe to muffler or;
3.5" collectors to 3" pipe to muffler or;
3.5" collectors and pipe to muffler?
Plan is to use Hooker Max Flow mufflers.
 
Not sure what your asking. According to the info I found on 5303 Hookers, they have 3" collectors. So how would you bolt a 3 1/2" collector to them?
 
why? what rpm are you shifting at. If you aren't over 7K, bigger tube headers probably aren't going to net you much, if anything at all.
 
I would not run anything under 3.5" collectors and exhaust pipe and mufflers on that. It will need every bit of it with no step downs, IMO.
 
FredS said:
why? what rpm are you shifting at. If you aren't over 7K, bigger tube headers probably aren't going to net you much, if anything at all.
Click to expand...

People say the same about bigger valves and ported heads, but it ain't true.
 
The only thing I don't know is the collector size on these headers, but since it is a race condition we're in, I would just do the collector size right on out to the dump.
Good muffler IMO. Striaght through or off sets in and outs?
 
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I changed mine out to the 3.5 inch collector. If you are NOT running mufflers, or the engine is small, you might do better with the 3 inch collector.

I forget the brand I bought.
Good headers have slip on collectors.
 
We are running a 417 stroker in a '66 Cuda . 100% street legal . 1 7/8 pipes to a 3 1/2 " collector , reduced to 3" to flowmaster race muffs . Runs 7.0-7.09 in the 1/8th and 10.90 in the 1/4 @ 123.80 . 60ft. is 1.45-1.43 . On a well prepped track "The 'Cuda that Could" can run 10.68 sec. That is with 9"x28" M/T Radials . Carries the front tires for the first 100 ft. You are almost there , good luck
 
yes, they come with 3" slip on collectors. To change them, I simply have to slide the 3" collectors off and slide some 3.5" collectors on.
I've found all kinds of conflicting info. Some say 3.5 is too big, and some say it's good for racing, but not street. The car isn't a street car other than an occasional cruise night.
 
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FredS said:
why? what rpm are you shifting at. If you aren't over 7K, bigger tube headers probably aren't going to net you much, if anything at all.
Click to expand...
Not talking about the tubes, they are big enough. I'm talking about the collectors. Shifting at 6500 but still experimenting
 
64physhy said:
Not talking about the tubes, they are big enough. I'm talking about the collectors. Shifting at 6500 but still experimenting
Click to expand...


It will like the bigger collector, if and this is the IF, you are using mufflers, or IF you get the collector long enough. A big short collector will kill it, just like a long small one will.


I used the Dynatech collectors. Reasonably priced. Well made.
 
I have a 394 ci motor and Pipe Max said to run 1 7/8 primaries and 3 1/2 collectors. So that is what I built. Mine is a pump gas motor and runs 6.20' s in the 1/8 @ 110 mph.
 
D-50394 said:
I have a 394 ci motor and Pipe Max said to run 1 7/8 primaries and 3 1/2 collectors. So that is what I built. Mine is a pump gas motor and runs 6.20' s in the 1/8 @ 110 mph.
Click to expand...
X2!!!
If you want an exhaust system that is tuned to your eng. PipeMax program is a good place to start.....and finish:D
 
D-50394 said:
I have a 394 ci motor and Pipe Max said to run 1 7/8 primaries and 3 1/2 collectors. So that is what I built. Mine is a pump gas motor and runs 6.20' s in the 1/8 @ 110 mph.
Click to expand...
Are you running an exhaust, or straight out of the collector?
 
Remember that as the exhaust gases (pulses) gets further and further from the head exhaust ports the exhaust gases start to cool. As the exhaust air cools it condenses. So in theory if you the leave the pipe the same size as the collector the gases will actually have more space because the gases are cooler and less dense which requires less space (pipe diameter).


treblig
 
yellow rose said:
It will like the bigger collector, if and this is the IF, you are using mufflers, or IF you get the collector long enough. A big short collector will kill it, just like a long small one will.


I used the Dynatech collectors. Reasonably priced. Well made.
Click to expand...
As of now, the plan is 3 1/2" X 12" merged collectors (Hooker) into a 3" reducer with Hooker Max Flow or Dynamax bullet mufflers. Thinking of going 3 1/2" all the way through, but worried it might be too big.
 
64physhy said:
As of now, the plan is 3 1/2" X 12" merged collectors (Hooker) into a 3" reducer with Hooker Max Flow or Dynamax bullet mufflers. Thinking of going 3 1/2" all the way through, but worried it might be too big.[/QUOTE



Probably not too big with the muffler.

Don't forget the muffler adds collector length.
Click to expand...
 
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