• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

426 Hemi Dual Spark Plug Aluminum Heads - ID Help

64 Sportfury

FBBO Gold Member
FBBO Gold Member
Local time
10:06 AM
Sep 13, 2011
Reaction score
Nassau, NY
A retiring engine builder, former drag racer here in FL asked me about a set of dual plug aluminum 426 Hemi heads he has sitting in his shop. I was hoping someone here would be able to ID them so he can put them up for sale. They have larger valves both Int. and Ex. Int. 2.35 and Ex. 1.935. He has SS valves that fit the heads which have bronze valve guides. I forgot to check if the second set of spark plug ports are threaded. I can't tell in the photos I took either. He doesn't recall how he got them so no history there. Please see the attached photos if you can help it would be appreciated.
20240207_114932 (1).jpg

Not saying it is but it's possible the SM # could be Sox & Martin.. They are a fairly serious race piece...
I had a set of those once. Mid 70's Mopar over the counter piece as I recall. Are the exhaust ports square or D? I thought mine were D-port but I went through so many junk aluminum heads before getting smart and buying a set of Stage V's I can't remember now.
Thanks for the responses 1 Wild R/T and Runcharger. I will follow up on this info and report back. I don't have a photos of the exhaust port shape but will get a few. He is about 75 yrs. old and does/did mostly GM stuff. He's got tons of nice period engines, parts, etc. He has some serious intake manifolds that circle the upper walls of the shop as well. You both have given me good info to pass on.
Found a little more info...

Casting number 3614433 is actually part number P3690038, it was out of production and no longer being sold by mid year 1976...
Not sure exactly what your heads are from the pictures. I have a pair of Stage V dual plugs for my next build.

100_1453 [640x480].jpg

100_1454 (2).jpg
Auto Transport Service