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- - head cc (https://classracer.com/classforum/showthread.php?t=29958)

on a sb chev head with 73 cc how much machining is required to move 10 cc and on a 61 cc head how much to move it approx. 9 cc ? Two different combos we are working on . thanks .........

Geez 223 guys don't know any more than i do . The reason i ask is my machinist isn't too interested in STOCK and i don't want him to screw up my heads . He says he can't understand why i want to spend money to go slow !! See what i am dealing with ?

with that chamber some where in the neighbor hood of 1cc per .008-.010 removed from the head,,i would cc the head after .030 was removed just to see gmonde

I milled them all and had factors recorded for most heads..
441 type chambers was around .0058" per cc
461 type heads was around .0065" per cc

This is from memory as it's been a long time......so you do need to mill some and check it to see where your at....should be close though.....I did this work for well over 10 years everyday....

Its been awhile but I believe I cut 6 thou per CC on the low comp. open type chamber of a 441/993 type head and 5.5 thou per cc on the higher comp (461/462/etc.) heads. Sneak up on it as you cant put the material back on after its cut. Even if you have to take them back to be cut some more and spend a little more $$$ after rechecking depending on how close you want to get. Be sure to use a CERTIFIED Burette and colored alcohol. Its cheaper than preping a new set of heads and better than sinking and/or facing the valves.
Rich...are your sure about cutting .0065 per CC? I dont remember cutting that much per CC???? I could be wrong ! Im old.

thanks very much for your replies, i knew you guys would come thru . One set of heads are 882 and the other are LT1 . Thanks again

Quote:

Originally Posted by X-TECH MAN (Post 225018)

Yes Terry I am sure and you have it backwards....smaller chamber needs more cut per cc and the bigger chamber needs less.....

The larger chamber has more surface area.......less to cut/cc

I had an old sheet with all the common heads and not just Chevies......I did exactly as you suggest.......cut some and check them and our factors were always conservative......I never cut a head to small by accident.........

I milled and CC'ed most heads done in our shop (Crow's Head Shop) and we did machine work for other shops along with our own customers and engines....I did heads for T/Ks. I made them +.5 cc'sfor T/K and sometimes spent hours doing this
.....we did a ton of machine work for them. Charlie Weston....Hoffman and Our shop did all of Ralphs machine work.....

I miss my Storn Vulcan Blockmaster......and my FN boring bar.....I had them both going at once a lot......Not to many mishaps...only 2 I can think of and neither was terminal for parts or machines...LOL

Quote:

Originally Posted by Rich Biebel (Post 225034)

You are correct. I seem to do more things backwards lately. I just dug thru some of my old papers and saw it is as you say. Thanks. . Damn......I must be getting old.....LOL.

When we were racing I used to angle mill the heads, I see no mention of that here, is that not done, or required?