Head selection

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72ScampTramp

72ScampTramp

Scamp Tramp
Joined
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Realizing my goal may be to lofty I put out a feeler for BB cast heads.. I got a few good replies but one is a better deal then the other im sure just not sure which one it is Im not sure which one is better. Now I know for a fact that the 452s have hardened seats. Not sure about the 346s. The flow numbers are nearly identicle but these 346s have been worked a bit. Whats your opinion?



"I have a set of 452 heads off a running 440; they're complete, had them cleaned & checked for a motor I'm building but the build changed. Guides are a bit worn but everything looks good overall. I'd like to get $100 for them, + shipping.
I'm in northern Idaho. Let me know if you're interested"




"if you want a little less head Ive got some 346's that came off a low mileage 400 (60k'ish) they have been bowl blended and gasket matched, valves lapped in. You would need to throw some springs on for your cam. you can have em for $100 plus shipping. let me know!"
 
The 346s IMO have slightly better ports but are more prone to crack. In both cases, they have induction hardened seats... If there was a valve job done on them at some point, the hardened layer is thin or gone already. Not a big deal but I wouldn't consider any core heads as being fine with factory seats. Sorry if this didnt help you much...lol. But it's basically the same head.
 
Actually It does help. I knew they were close to same spec of head. Didnt know if one casting was better then the other. Sounds like the ones that have been port matched and gasket matched may be a better value.
 
915s with the 2.08" valves are best. Double check the valve size as many 'extra' castings got the smaller valves and installed on "ordinary" engines, not just super commandos and magnums.

The 906s were equal flow with larger combustion chambers (about .5 less compression).

The MH head had intake valves 'relieved' and lower compression again.

Compression on the stock engines was controlled by wrist pin height (piston deck height) and combustion chamber size.

Maybe Mopar Performance still sells valve pocket porting templates? If you're handy and good with your hands pocket porting would make a significant difference to the flows. Valve grinder can backcut the valves and increase flow as well. Matchporting is also quite simple and easy for a novice. Actual porting is best left to the pros - unless you've got spare heads in case you cut too thin? A thinned casting can also crack after the engine is fired up and heat cycled ...

Buy the heads best for your desired compression ratio.
 
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