Inliners International Forums General Discussion Engines 848 head

I've tried to search this but can't find anything. Does anyone know the CC of the combustion chamber on a stock 848 head. I just did major head work, milled .110, sunk the intake .125, installed PG valves, removed .125 from the valve stem, clearanced around the exhaust valve, install Buick 455 dual springs, removed the valve guide in the intake runners, and cc'd the chamber at 73.8 ccs. I know sinking the intake valves and clearancing the exhaust valves adds volume, but I am wondering if I gained any compression. Unfortunately we did not cc before the operation.

Thanks
Warren

Tom Langdon says 79.1cc, typically the factory data is the smallest legal volume. The actual castings run larger, 3-5cc more is common.

Hi Warren . . . the volume of the 848 head has been discussed several times here on the forums. Most recently:
Inliners post circa '13: What is the compression ratio?
suggesting a volume of 79.1 (as panic has stated) - so you've reduced the volume by ~5.3cc or 6.7%.

regards,
stock49

Sinking the valves does several things. One it makes the airflow much worse than before you started, even with increasing the valve size. Second, it killed the compression you gained by milling the head.

I did it because I could. This is a about experimentation. If all else fails I have several heads I can start over. My main concern was that I didn't make the combustion chamber bigger than stock. Thanks for the cc info.

Warren