Atm, 1.78/1.50 The exhaust valve in the pic is a stock 360 1.60 turned down to 1.50 for testing. The face is is wide enough to be cut and land right on the stock 1.50 seat in the head. I've done 1.88's too.
nice thread, great information. Did the original author die and become a legendary member ? lol I know he was at least 120 years old. Pretty smart old duffer.
I still get hbd's.. on not my birthday. 121 now.....though after 20 years of laying carpet, playing drums in bands ,building motors, fixing my family's cars ..I feel about 121.5 yrs old
I started this thread, so I'm adding this 302 info to it, starting with this video. I will also post here pics and details how like this thread was orginally intended.
What's the most cfm has anyone gotten from their stock 318 heads ( from porting ) and adding larger valves ? 260cfm possible ?
. Pardon me while I whip this out. I think the question is what's the max you have gotten out of a pair of 318 heads?
I have not max ported a 318 head with a 1.88. With a 1.78 valve they kind of stop in the 215-220 cfm range. I think 230-240cfm with a 1.88 is about it. I did some 'not all out' 1.88 273 heads and they went around 225 cfm. They end up near 140-145cc and that's tiny for anything but a 273/318. I don't think they would be the best choice for 6500+ rpm and or more cid..but it depends on the parts and pieces I'd suppose. You need so much volume to be able to 'refill' at that rpm
