Here are the dyno results where several sets of headers are tested on a 314” Y.  Engine particulars include a 3.810” bore (+060 over 292 block), 312 crank with turned down mains, C2AE truck rods, ported ‘G’ heads, 12½:1 compression ratio with Dykes rings in the top lands, extrude honed Blue Thunder aluminum 4V intake, Isky 505-T cam with 254° @ 0.050” duration ground on 108° lobe centers and installed at 106° intake lobe centerline (2° advance), 1.6:1 Dove rockers, and a 830cfm Holley vacuum secondary carburetor sitting atop a 2” HiFlo spacer.  Engine performance comparisons are made in the 2500-6800 rpm range.

Here are some specifics on the headers involved in this test.

1. EMC headers – 1.750” X 1.875” stepped tubes with 3” merge collectors.
2. Chrome drag car chassis headers – 1.750” tubes with 3½” collectors.  Tested with 6” long 3½” diameter collector extensions and also with 27” long 3½” diameter collector extensions.
3. Upswept dragster headers – 2” tubes with 3½” collectors
4. Sanderson truck headers – 1½” diameter short length tubes with 2.375” collector openings.
5. Fenderwell headers – Circle Track specials, 1.750” diameter & long tubes with 4” collectors.
6. Fenderwell headers – Drag car specials, 1.625” diameter & long tubes with 3” collectors.

To keep the graphs from being too busy, they are broken down as two sets with the Sanderson headers being common on both graphs for comparison purposes.

Scoring is calculated from the 2800 thru 6800 rpms range and is as follows:

Sanderson truck headers, 1½” tubes, 2.375” collectors    - 1718 pts.

EMC headers w/o mufflers (stepped tubes, 3” collector   – 1715 pts.

Upswept dragster headers w/2” tubes, 3½” collectors    –  1702 pts.

Chrome drag car chassis headers w/27” extension        –   1700 pts.

Fenderwell headers w/1.625” tubes, 3” collectors       –    1692 pts.

Chrome drag car chassis headers w/6” extension      –      1690 pts.

Fenderwell headers w/2” tubes, 4” collectors          –       1679 pts.

Here are pics of the various headers that were used in this particular test.

EMC headers – 1.750” X 1.875” stepped tubes with 3” merge collectors.

Chrome drag car chassis headers – 1.750” tubes with 3½” collectors.  Tested with 6” longer 3½” diameter collector extensions and also with 27” longer 3½” diameter collector extensions.

Upswept dragster headers – 2” tubes with 3½” collectors

Sanderson truck headers – 1½” diameter short length tubes with 2.375” collector openings.

Fenderwell headers – Circle Track specials, 1.750” diameter & long tubes with 4” collectors.

 Fenderwell headers – Drag car specials, 1.625” diameter & long tubes with 3” collectors

The horizontal axis is as large as the site will permit in being ‘500’ wide.  Although the graphs view fine on my end, I can only imagine the number of different monitor and viewing properties/attributes used by other YBF forum viewers.  Some better, some worse I’m sure.  I did have the option of using Photobucket or another hosting site which would permit a larger horizontal viewing but I’d rather these graphs were permanent to the site and also sized where the text is not rolling off of the right side of the screen.  Using an external host site leaves the potential for the graphs to eventually disappear from the site if the files at the host site are removed or renamed.

From a site loading standpoint, I do still have room to stretch the vertical axis on the graphs.  This would essentially make the graphs square; the Y axis (vertical) would then be the same size as the current X axis (horizontal).  If stretching the vertical axis would help the viewing, then I can do that on future graphs.  Just let me know.

Gut feel says the Sandersons are going to outperform the Rams Horns except maybe in the very low rpm ranges.  That same gut feel says the Rams Horns are going to be better than the ’57 & up cast iron manifolds but that will be verified in the ‘big’ exhaust test that’s coming up.  The Sandersons thus far with their smaller tubes do work well on the engine combinations thus tested.  But here’s a link to a 272 that was tested with the EMC headers and Rams Horns as that's the only Rams Horn test I have on file.

Exhaust Testing – 272 Y-Block

I’ll take you up on the offer on the header loan.  The more the better at this point.  Go to this website for contact info and/or a shipping address.   http://www.eatonbalancing.com/   

Here’s a list of exhaust tests that are in the planning stages thus far.

Early single exhaust manfolds with crossover pipe and a length of 2” exhaust pipe.

’57 exhaust manifolds with dual exhaust pipes.

Fenton exhaust manifolds with dual exhaust pipes.

Rams Horn manifold with dual exhaust pipes.

EMC headers w & w/o muffers and variety of exhaust extensions.

Burnette T-Bird headers (shorty design and Tri-Y).  Not firing order specific.

Pickup Tri-Y headers with a Y specific firing order into the tubes.

1 5/8” tube fenderwell headers.

1 ¾” tube fenderwell headers.

1 ½” tube Sanderson pickup headers.

1 ½” tube shorty heades with square collectors.

Reds two tube car chassis headers.

pegleg (11/15/2010)

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Ted for what it's worth.......thanks for your time effort and expense!

Yes!  Thank you Ted!  You give us so much info that we could not get on our own without great cost.

Glen.  It’s your call on sending the headers or not.  They can be tested on your engine against another ‘known’ set and comparisons made that way.  But if you send them, I’ll test them on the dyno mule with the other headers.

Al.  Same deal.  If you send them I’ll include them in the test.  Your call though as there are plenty of headers here now to test.

Mark.  Be sure to include a return shipping address and phone number in the box with the headers.  Would like to get them back to you as soon after testing as possible.

Wayne.  Afraid I don’t have any spreadbore Holleys here so that option is out.  But I have tested vacuum secondary carbs against double pumpers and the vacuum secondary carbs when tuned properly and being equally sized outperform the double pumplers on the bottom end of the scale.  They are equal on the topend of the scale all else being equal.  The dip in the torque curve that’s observed with the EMC headers does go away when mufflers are added.  The muffler part of the test is just not in this particular thread though.  The Sanderson headers without mufflers had a very strong lowend torque curve without the lowend dip that’s evident with the larger collector sized headers.  At this point, there’s a strong relationship in the lowend torque numbers and the collector exit size.

Here’s the link to the thread including graphs for the 314 engine with EMC headers with and without the mufflers.

Exhaust Testing – Mufflers versus No Mufflers