I am curious to know how many CC's were lost in the process of opening up your head to match an 84mm, 85mm, or 86mm bore.

Please include if head was a P-72 or PR-3 so original chamber volume will be know.

Thanks- Please no comments on why you should or should not do this to your head. I just want the info.

 

I had a gsr head spotfaced to 85mm and it was 43.5cc...way too ******* big.

I milled that **** like 30k.

 

84.5mm chamber P72-1 head = 38cc after about 30 thous worth of milling.


Greg

 

Thanks so much guys.

Dave was that head 43.5cc's after the .030 mill or before.

Cheetah what is a stock GSR chamber isn't like 41.7CC Did milling .030 bring the chamber back to that small of a size?

Anyone with more info please feel free to add.

 

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<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by asubennett &raquo;</TD></TR><TR><TD CLASS="quote">Thanks so much guys.
Dave was that head 43.5cc's after the .030 mill or before.
</TD></TR></TABLE>

Before...41cc after milling i believe.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by asubennett &raquo;</TD></TR><TR><TD CLASS="quote">
Cheetah what is a stock GSR chamber isn't like 41.7CC Did milling .030 bring the chamber back to that small of a size?

</TD></TR></TABLE>

yeah the stock 79mm chamber is 42cc but this head's chamber was opened up to 84.5cc and milled about 30 thous to produce 38cc. The chamber was also reqorked and had flat valves when i cc'd it.

greg

 

Thanks so much guys. I didn't realize so much volume could be reduced by milling. It is encouraging to hear. I wonder why so many people disocurage spot facing heads if their main gripe is the resulting lack of compresion from opening up the chamber.