Part 13 - Checking GM 781 Cylinder Head Chamber and Port Volume -In Depth Performance Engine Build 620+ Horse Power Street/Strip Pump Gas 454 Big Block Chevy
my intakes came in at 255 bad port, and 252 good port. c18 74 781 heads. I forgot what my machinist told me he measured my combustion chambers at, but since I'm having the 2.19" intake and 1.88" exhaust valves installed, I did some unshrouding work, and now the combustion chambers are measuring 122cc. I did a port match on a felpro gasket, raised the roofs a little, and ground out the rocker arm stud boss on the bad ports. Now the bad ports are measuring 270cc, and the good ports are 265cc. I haven't touched the exhaust side yet, but I only plan on opening the throats to 85% of the 1.88" valve, and removing all the casting flash.
Great videos! When measuring or comparing port volumes before and after (stock vs. ported/new valves), should you take into account the shape of the valve that will be used? As in, a stock valve might be tulip shaped (less port volume), and a performance valve might be nail head type (more port volume). Or is it not enough of a difference to worry about? Thanks!
@@excelerater Or YOU can send me some of those Whiz- Bang Aluminum Heads or $3000. I also need a extra $700. For a tunnel Ram. I already have short block & two school holley carburetors. Thanks
Why wouldn't you is my question? Nothing like old school and learning a thing or two and having some fun while you're at it. If you don't enjoy the finer things in life, then motor on down the highway!
