Larry: Thank you for your research. As a possible further assist, I've created a tiny URL and copied the text from the ad for server readers. Apparently if you have matching heads and blocks, all manifolds are interchangeable. I've read that the '55 heads are somehow preferred on later blocks. So, if 331/354 heads are installed on a 392 block, manifolds will not fit. (But it is apparently done, so what manifold is then used??? Spacers?) The ad does answer my previous question of manifold heat as somehow routing exhaust gas through one section of the base of the intake manifold for carb heat. I'm wondering what intake manifold was used on "Adam" and other early 331 race engines? Anyway, this link should be easier to use and the text is shown below. C-300'ly, Rich Barber 1955 Chrysler C-300 Brentwood, CA (Allergy season in full swing as trees and plants are in bloom and it is too dusty dry to wash the pollen out of the air. Beautiful weather, but the state and county are out of water and money while still having an excess of bovine fecal debris.) http://tinyurl.com/bhr5qe Weiand's part# 7263. New low profile, dual four intake manifold. It fits any of the 1955-58 Chrysler 331, 354, and 392 hemi engines. It's aluminum (2-4's) made for the Carter or Edelbrock AFB series carburetors mounted inline. It has the standard square bore mounting but they would sit too close for Holley's to fit inline. Designed with a heat crossover passage underneath for quick warm up on the carburetors. Take some weight off and add some class to that impressive engine. This can get many old hemi racers confused. All of the intake manifolds from the Chrysler 331 to the 392 were the same width. The 331 & 354 engines had narrower cylinder heads because of the shorter deck. The 392 engines had a taller deck and wider cylinder heads. Regardless of what you hear from old racers, this is how it is. The old hemi racers liked to use the narrower heads off a 354 on the 392 and that's when you had to have the spacers. Long story, short if you have the same cylinder heads on your engine, the manifolds will fit. One more tidbit of good information. The early '51-54 Chrysler hemi engines can use this intake manifold but will require a remote thermostat housing because the stock intakes have the thermostat housing built in the intake manifold. This dual four manifold does not have the T-Stat opening in it. It does have 1/2" pipe thread water ports on each side and can be easily used with steel braided hose and fittings and provides a nice set up and great cooling that way. -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of JettLarry@xxxxxxx Sent: Tuesday, February 03, 2009 8:37 AM To: chrysler300@xxxxxxxxxxxxxxx Subject: [Chrysler300] New Information on 2x4 manifolds filling ALL early hemis 331 to 392 Consensus was that 392 manifolds would not work on 331 and 354. These folks disagree. Plus here is good news for earlier hemi's in your fevered imaginations.. http://marketplaceadvisor.channeladvisor.com/StoreFrontProfiles/DeluxeSFItem De tail.aspx?sid=1&sfid=78392&c=613663&i=6459401 ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/