Quote:
Originally Posted by Kube
I have always wondered why Ford made these. Being the same compression ratio as the stock heads, the only advantages I can think of are weight (who cared?) and better heat dissipation.
I can understand the cast and aluminum heads that were offered with higher compression but these???
Anyone have any ideas?
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Well, your first reply caused me to remember I had downloaded rumble seat's (rest his soul) pdfs in the past, so checked to see if anything explanatory was there. It appears these are pre-war 81a heads as well by his reckoning:
"The 81A heads (24 stud) came in either aluminum or cast iron. Both were rated
the same at 6.2:1 C/R. Both have right and left heads. The aluminum heads have
combustion chambers of 82cc for the right head (part #6049) and 84cc for the left
head (part #6050). The cast iron heads have combustion chambers of 79cc for the
right head (part #6049) and 81cc for the left head (part #6050). Interesting....
same C/R with different cc’s.... wonder if flat top versus semi-dome pistons
account for the variation?"
The larger chamber size for the aluminum is consistent with the 21 stud ('37-8) being lower compression than iron heads (supposedly for truck app, but I have a passenger engine with them, so.....?)
As for the original idea of the thread, you've demonstrated the effect of less common knowledge being useful in recognizing seemingly unusual market pricing.