Originally Posted by Racer
The most benefit from "porting", is not actually "porting", but valve and bowl work. Gasket matching like what you have done is virtually worthless.
The exhaust side of these stock heads is weak. Then there is also a small bump. Gasket matching as you call it, opens up a substantial amount of extra exhaust flow if you blend it all the way into the chambers. I did.
Add a bit of home chamber polishing and a 3 angle valve job and you have a decent set of heads relatively cheap.
These were also the early model quench heads, not the later big chamber beasts.
Most info I've read on porting says a home job does about 60-80% gain of what a pro job would produce.