Can anyone explain me the procedures of pocket porting your heads? Is it significant in performance engines? What type of tools to use to gasket match your intake manifold and heads? Thanks for the advice :TU:
PORTING IN THE POCKET IS TO MAKE UP FOR THE RESTRICTION CREATED BY THE VALVE GUIDE AND VALVE STEM, MAKING THIS AREA BIGGER AND STREAMLING THE VALVE GUIDE ALLOWS THE VOLUMN OF AIR TRAVELING THROUGH THE PORT NOT TO JAM UP IN THIS AREA. THERE ARE LOTS OF PICTURE BOOKS AVAILABLE AT BOOK STORES ON THIS SUBJECT, YOU DON'T EVEN HAVE TO BUY THEM TO GET THE IDEA. IF YOU CAN GET A LOOK AT A CNC PORTED HEAD AT A TRADE SHOW OR TALK TO A LOCAL RACE ENGINE BUIDER YOU CAN GET A GOOD IDEA OF WHAT'S CRITICAL IN THE PORT. GOOD LUCK
I have a set of 1972 455 Buick heads; what type of gains should I expect if I were to have these heads pocket ported? Thanks for your response:TU: .
Chris, check out my post "My heads are back from the porting shop". These numbers are what you could expect with stage 1 valves and a very good machinist doing the work. My heads were originally 73 standard castings. Brian
CHRIS, CLEANING UP THE POCKET WILL HELP A LOT. BUT, STOCK HEADS CAN ONLY GET SO GOOD. FIGURE THE BEST PORTED STOCK IORN HEADS FLOW IN THE 275-280 CFM RANGE. A STOCK RECT. PORT BIG BLOCK CHEVY FLOWS AROUND 330 CFM, A STOCK HEMI IS ALSO AROUND 330-340 CFM. THE NAME OF THE GAME IS AIR, MORE AIR=MORE FUEL=MORE POWER. EVEN NEW CAR MFG.'S HAVE FINALLY FIGURED THIS OUT, AND BETTER GAS MILEAGE IS A BY PRODUCT OF MAKING THE ENGINE EFFICIENT,THEY ARE MAKING GREAT POWER WITH SMALLER CUBES. A 455 CID. ENGINE IS VERY BIG BY TODAY'S STANDARDS, GETTING ENOUGH AIR INTO THESE BEASTS IS DIFFICULT, MANY TIMES GOOD HEADS ARE CHOKED BY A BAD INTAKE OR EXHAUST. BEFORE YOU PAY ANYBODY TO DO WORK FOR YOU GET SOME BACKROUND ON WHAT'S INVOLVED, IT MAY BE CHEAPER TO BUY BETTER HEADS. GOOD LUCK
How much air does a healthy 455 needs? Is there a formula to figure out how much air these engines need? If buying new heads are best, how can I get the research? Thanks for your help! I have been beaten before :stmad: , and I can't afford to lose anymore money.
I think for a N/A engine, if you're looking for say 500hp - you want the intake ports to flow at least 250cfm. Exhaust side should flow approximately 70-80% of the intakes for a good set of heads. Not sure what the best iron exh. ports are flowing.o No:
