Re: 12 cyl alum heads other parts

Posted by Owen_Dyneto On 2013/1/19 10:56:48

I can't help with all your questions but maybe this will be of some assistance. The Twelve was stroked 1/4 inch for 1935 (445 to 473 cubic inches) so certainly the crankshafts and connecting rods are different before and after. Good cranks and rods certainly have value, especially since the rod bolts were forged intergrally with the rod itself. There was a cylinder block change for 1938 so some differences there as well though I'm not sure just what they were; casting date on the block should identify it if the motor # isn't readable. No real value to intake and exhaust valves are they are available in better metallurgy than the originals. Repro pistons are readily available though not (to my knowledge) in autothermic strut design so if the pistons are in remarkably superb condition they may have some value. New reproduction aluminum cylinder heads are available from at least two sources so I doubt it pays to try to weld and otherwise repair the heads, the alloy was quite primitive compared to the alloy used in the repro heads and the chances of the repairs being permanent isn't probably all that great. The valve lifters/silencers may have some value but there are folks who specialize in rebuilding these; you might check the parts lists to see if they are same thruout the Twin-Six and Twelve run. The same lookup should tell you about interchange of the manifolds.

If you're looking to sell, your best bet maybe to one of couple of shops that specialize in rebuilding Twelves.