Are the best heads, as far as GM iron goes (besides Vortec) the 186 castings? Reading David Vizard's book seems to show that these heads with work can give some good horsepower. But then again, he knows what to do and what will go well with what, so the numbers probably aren't as realistic as what I would get, but I know where I can get access to some 'good' stock heads and were wondering if 186's were the 'best'. I know, I know...aftermarkets will do better and cost less than stock machined heads, but just curious anyway.

Also, don't know difference between closed and open chamber...are closed better?

461X...60-63...283/327..Camel hump,no accessory holes,larger 172/64cc port volumes, 62cc chamber

461....64-66...327......Camel hump,no accessory holes,160/62cc port volumes,62cc chamber

187....69-70...350..........Camel hump,64cc chambers,accessory holes (watch out, if they are on a 87-up engine 187s are cheap L03 305 heads)

291/292 heads

462 heads

040/041/041x

414

492

186s as you mentioned, are great heads.
all these heads are of the "camel hump" family, but some dont all have the camel humps cast into them

don't take my words as gospel, but i think closed chamber heads just means 64cc or less chambers. while the 70cc and up heads are open chamber.

What about 416's?

14014416...80-86...305..........1.84"/1.5" valves, 58cc chambers

I had a set that flowed pretty good, and they are very easily ported and ground for 2.02/1.60 valves which turn them into 64cc chambers.

the problem with pretty much any 305 head is that they were cast after 1975 and those castings are lighter and thus more prone to cracking than the pre-75 heads. i think the best 305 heads came on the 87-up LB9 engines. (i think the LB9 heads are 193s with stock 1.94/1.5 valves)

I had a set of 186 heads that I had "worked"..big valves..rocker studs..bowl work. They flowed 240@.500 and 175 on the exhaust. The down side..they cost me close to 1000.00 b4 I was done