Flathead V8 Compression Ratios...6,020 choices

Ol' Ron said:
Jim That's an incedable job. Having worked in this area for years, I know just how much time you've put into this. I will send you the info I have in the CR checker.
Thanks again for a great job.
OL' Ron
Click to expand...

Ron,

Thanks and looking forward to receiving it.
 
An excellent job blown49 and thanks to all involved, a hard copy is now sitting on my printer tray.
 
Sadly, Jim Leis (Blown49) passed away since this thread. He was a regular contributor and is missed!
 
He put a tremendous amount of sheer hard working into all the calculating and double checking. I don't think there will ever be a better chart than his! He used to phone from time to time, always discussing arcane flatheadiana and his careful decoding and listing of critical facts and dimensions.
 
It saddens me to find out the passed away, we had numerious conversations and I found him tobe very knowledgeable. My condolences to his family.
Ol' Ron
 
I know this is an old post but I was doing some reading and I could not open the pdf attachment. Does anyone else have this? Thanks Gary
 
Thanks guys I got it and printed it. It kept telling me I wasn't logged in every time I tried to open it. Beats me.
 
Bringing this old thread back up after recently acquiring a set of 41T heads. Bruce Lancaster always used to talk about the desirable Denver head compression ratios (81AS, 19AS, 99AS). If the data in the spreadsheet is correct, seems to me the 41T had a pretty desirable factory compression ratio as well? Any thoughts or comments?
 

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It is my opinion that anyone who just slaps a set of heads on their engine without carefully measuring them and subsequently modifying them for optimum quench and compression is leaving a significant amount of performance and economy on the table.
 
I suspect the table has a typo for the 41T combustion chamber size. The chamber in your pictures matches pictures I have of another 41T head. The combustion chamber looks very similar to a 29A head, and that is listed as 79 cc chamber. The "T" in the part number is for truck use, a lower compression application as shown by the other truck heads in the chart (81T, 99T, etc.). I suspect the 41T is closer to an 82 cc chamber instead of a 62 cc chamber. Best way to know is to put a spark plug in one of the chambers, drop a flat clear plate on it, fill it with the fluid of your choice from a graduated cylinder, and get a true measurement. Please let us know what you find if you measure a chamber.

Picture of a 29A combustion chamber:
558918
 

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