Header Flanges, Gaskets

1 5/8" Plain Header Flanges - 3/8" thick
1953-57 241-270-315-325" Dodge
(Part Number 25702D38).  Also available with 1 3/4" and 1 7/8" port diameters
and flange thicknesses of 1/4", 5/16" and 3/8".
    

1 7/8" Finished Header Flanges - 3/8" thick
1954-58 354-392" Chrysler
(Part Number 20703F38).  Also available with 1 5/8", 1 3/4", 2", 2 1/8", 2 1/4", 2 3/8", and 2 1/2" OD
Starter Tubes and flange thicknesses of 1/4", 5/16" and 3/8".

Starter Tubes are approximately 2" long.

  2 1/4" Finished Header Flanges - 3/8" thick
1958-up 350-361-383-400-413-426-440 Aluminum "B-1" Head
(Part Number 20722J38).  Also available with 2", 2 1/8" and 2 3/8" OD
Starter Tubes and flange thicknesses of 1/4", 5/16" and 3/8".

Starter Tubes are approximately 2" long.

      

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CUSTOM HEADER FLANGES:  While the above Header Flange Listing is quite comprehensive, because we do so much CUSTOM designing in this area, one must understand that we offer much more.  Based on already existing header flange patterns, over the years we have made header flanges:  (1)  WITHOUT PORTS for customers using the header flanges to seal the exhaust side of the motor or customers machining the exhaust ports in the flanges to match a reshaped/relocated exhaust port;  (2)  WITHOUT BOLT HOLES because the customer wanted to drill the bolt holes themselves so as to locate the ports in the flange relative to the ports in the cylinder head a certain way;  (3)  WITH SMALLER than normal exhaust ports because the flanges were going to be used as SPACERS (between a header and a head) to add clearance to a starter, oil filter, etc.;  (4)  in Finished Header Flanges, WITH PORTS LARGER than normal relative to a tube size so that a smaller tube size header could be built but with a full size exhaust port in the header flange (one that does NOT block exhaust flow out of the head); etc.  In some cases these design revisions are done at no charge but where custom drilling is performed (some movement of the bolt pattern relative to the standard location), there is a $15-25 extra charge for the time involved.  Where only ONE flange is desired out of a set of two, we charge 75% of the pair price due to the setup time involved just to make the first flange.  We do NOT make PURE custom header flanges (i.e. one of a kind designs where only one or two pieces are needed) due to the development time involved.  Header Flanges are made from Mild Steel Plate - NOT available in Stainless Steel.

¹ Port Size:　 ROUND PORTS:　 This is the Inside Diameter of the ports in the header flange measured in inches.　 ON ALL OTHER PORT SHAPES:　 This is the OD of the header tube measured in inches that, when reshaped, would fit into this port size.　 In other words, this dimension does not truly relate to the size of the port in the header flange but more relates to the tube size specified AFTER being reshaped to approximately match the port in the flange.  Keep in mind that we make many header flanges with several choices of port sizes.  We usually ship the flanges that match the cylinder head port AND the tube size being used as closely as possible.  There are reasons to NOT always ship the best match to the cylinder head port but that is usually due to customer requests or specific needs.  We always ask about this because we see no sense in blocking the exhaust port unless there is a good reason to do so.

To make header building MUCH easier, we supply the header flange with ports (those shaped other than round) sized about 1/16-1/8" oversize from a perfect match so that the tubes do NOT have to be shaped perfectly to be inserted into the port.  Port Shapes:

RD = Round,

OV = Oval,

RE = Rectangular,

SQ = Square,

DD = D-shaped port with flat on bottom in most cases,

SAP = Same Shape(s) As Port(s) in head.

NA = Not Available or Not Applicable

² Header Flanges are priced as a set which means V8 and V6 sets have two flanges (one for each head). Most other engines have just one flange in a set. There are several exceptions to these rules but, where applicable, they are all noted.  Unless specifically mentioned otherwise, all header flanges are 1/4" thick. If you would like thicker header flanges, add $16.00 for 5/16" or $24.00 for 3/8".  All thicker header flanges are made to order and delay header parts shipments about 3-5 days. 　　

Made to order Header Flanges are NOT returnable.

³ V8 and V6 Finished Header Flanges and Header Flanges w/Starter Tubes are shipped with a complete set of header bolts.

NOTE 7: On the W-2 cylinder head, the exhaust side bolt holes are so close to the exhaust ports that it is physically impossible to build larger header tubes due to bolt clearance issues. A combination of INNER and OUTER flanges is now used to allow the construction of larger tube headers on these engines.

The INNER flanges have ports that are on the small side and have to be ground to match the cylinder head. The INNER flanges also have two bolt patterns:

(1) The stock bolt pattern that allows the INNER flange to be bolted to the cylinder head. The stock bolt holes are countersunk so that flat head Allen bolts can be used to hold the INNER flange to the head. The depth of the countersinking is such that the top of the flat head Allen bolts are flush with the outside of the header flange.

(2) The second bolt pattern (twelve bolts) on the 318-360 W-2 header flanges is threaded to allow the OUTER flange to be bolted to the INNER flange. This second bolt pattern matches that used by HOOKER HEADERS so header gaskets are easy to find.

While not normally included with plain header flanges, we DO include the necessary bolts with either of these INNER or OUTER header flanges.

Header gaskets are used between the INNER header flanges and the cylinder head and between the OUTER header flanges and the INNER header flanges. Gaskets are NOT included with these flanges.

NOTE 22.5:  While standard 383-440 header flanges will bolt on to these heads, the ports in the header flanges will usually not match well to these aftermarket heads.  Also - the exhaust surface on these heads are enough DIFFERENT from the standard production head that these flanges can be made with much more material around the ports (promoting much better gasket sealing) than possible with the standard production cast iron head.  (A standard header flange on a production cast iron head is limited by the shape of the cylinder head above the flange and by the cylinder head bolts below the flange but these aftermarket heads are machined different and allow the header flanges to be made much wider - and we took advantage of that and made these flanges even BETTER!)

NOTE 37:  The W-2 head has been made with two different bolt patterns - a NARROW pattern and a WIDE pattern.  The NARROW bolt pattern is the same as that found in the production 318-340-360 cylinder heads and can be checked by measuring the centerline distance between the bolt holes on each side of the center exhaust ports.  That centerline distance is 3.97".  The same centerline distance on the WIDE bolt pattern is 4.75". 

We know of two other companies that make header flanges for the W-2 cylinder heads.  Each requires the purchase of BOTH Inner and Outer header flanges.  In contrast, we offer SINGLE header flanges for 1 5/8" and 1 3/4" headers to save some customers money (plus build a LESS complicated header).  For those having to build larger tube headers we also offer Inner and Outer flanges BUT our Outer flanges are available in THREE port size (the others only offer one).  ALSO - our W-2 flanges allow the use of spark plug sockets to change spark plugs (do NOT block accessibility to the spark plugs).  One of the other flanges we've seen TOTALLY blocks the spark plug area and has to be cut apart to allow spark plug changing - which needlessly complicates header design and construction.  The ports in our Inner and Outer W-2 flanges also have very good alignment with one another as well as with the head port - they do NOT block exhaust flow as we've seen in others' designs.

HEADER FLANGE DESIGN DISCLAIMER: On ANY header flange made to match ANY performance/racing factory/aftermarket cylinder head, due to the fact that the manufacturer - at any time and without notice, might reshape and/or relocate exhaust ports and/or relocate spark plugs and/or change the angle of the spark plugs - we can NO LONGER guarantee port alignment nor spark plug socket clearance. If you are using ANY of these "non-production" heads (or have ported heads) and are concerned with possible port misalignment, we will select the best possible header flange to match your exhaust ports IF you send us a tracing of all ports, bolt holes, and surrounding machined edges.  (Note that FAXing is not often accurate enough for our needs.)  There is a $10.00 labor charge (no discount) for comparing tracings to current flange designs.  There is also a custom flange drilling charge of $15.00 when it becomes necessary to relocate the bolt pattern to align ports to the port tracings as accurately as possible - and NOTE that custom drilled header flanges are NOT returnable!  Otherwise, should port misalignments occur, grind flange ports where needed. If spark plug or spark plug socket interference occurs, then modify flange as needed.

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