Header Collector Size?

[mike337]

I am putting the last pieces together on my 440 Stroker, and starting to think about headers.  It 493 cu in engine, (.30 over) with a Comp Cams XE275HL hydraulic cam, roller rockers, Indy EZ heads (75cc) with a Promax prepped 6-pack on top.  It will have a 727 behind it, and a sure grip with 323 gears.  Based on what I have reviewed on the board already, it would seem that most have had success with 1 7/8 primary tubes, but the second part of the header equation is rarely covered. 

What would be best on the collector size.  2.5, or 3 inch?

Mike

[tan top]

what size is your exhaust  

[mike337]

No exhaust system yet, so i can go any direction.  I will need the headers for the dyno run though.

Mike

[BananaDan]

http://www.dodgecharger.com/forum/index.php/topic,79186.0.html

Here's my setup, with pictures.  I haven't been told my headers or exhaust is crazy or too big and my 440 is .030" over but not stroked so I imagine you should be good up to the sizes I used.  From what I've learned (and someone keep me honest), the downside of going bigger on the primaries and collector is less low-end torque, more high-end HP.  Based on the troubles fitting these beasts in, if done again I would have gone with the 1 7/8" primaries and 3" collectors, but hindsight, yadda yadda yadda...  I don't know if you want to go down to that size with a stroker, probably wait for an expert to chime in.

Dan

[frederick]

With a 493? 3"

I've got pipemax so I could run it for you if you want more detailed info.
But I'd need a bit more information first.
Compression, Rod length, valve sizes?

[68X426]

Three inch, let that bad boy breath.

[Cooter]

Header primary size usually will dictate an "off the shelf" headers collector size...Not always, but most times.
The Primary size (1 7/8" VS 2") will depend on what size exhaust valve you are running. If it's a 1.810, you COULD get away with a 1 7/8" for good torque but the 2" would be better for maximum HP and torque.
If it's a 1.880, you will most likely need the 2" Primary...You usually want the primary to NOT be smaller than your exhaust valve, for maximum HP and Torque...

[mike337]

I have noticed that TTI headers with 1 7/8 primaries, are available with both 2.5", an 3" collectors.  That is the reason for my question.  The heads are Indy EZ for the 440, so are 2.19 x 1.81 valves.  Compression is calculated to be at 10.5 - 1. Will check on the rod length.

Thanx,
Mike

[frederick]

I found the rod length: 6.760

Pipemax suggests:

Primaries
Internal Diameter: 1.72"
Length:
Best= 42.3"-44.8" otherwise 29.8"-32.4"

Collector
Internal Diameter: 3.16"
Length:
Best= 23.9" otherwise 11.9" or 47.8"

So I'd say the 3" collector and 1-7/8" primaries are good choices.

[firefighter3931]

I found the rod length: 6.760

Pipemax suggests:

Primaries
Internal Diameter: 1.72"
Length:
Best= 42.3"-44.8" otherwise 29.8"-32.4"

Collector
Internal Diameter: 3.16"
Length:
Best= 23.9" otherwise 11.9" or 47.8"

So I'd say the 3" collector and 1-7/8" primaries are good choices.

A 17/8 x 3 header will easily support 600hp 


Ron