Need info on 3998993 casting GM heads [Archive] - Chevelle Tech

: Need info on 3998993 casting GM heads


Junkyard Dawg
May 2nd, 04, 6:49 PM
Need to know intake/exaust valve sizes as well as how many cc's the runners are. I already know they're 76 cc chambers. Thanks.

Wolfplace
May 2nd, 04, 7:05 PM
Originally posted by Junkyard Dawg:
Need to know intake/exaust valve sizes as well as how many cc's the runners are. I already know they're 76 cc chambers. Thanks. =
1.94/1.5 The newer ones are cast in Mexico.
They should be around 155-160cc's

71454Chevelle
May 3rd, 04, 6:02 AM
Sorry to jump in on your post, but I have a question about the 993's.

How does this casting head respond to maybe larger valves and some bowl work? I have a set of these from a 400 SB and trying to decide if they will be worth messing with for a "grunt" 400 in my Suburban.

RB69SS396Conv
May 3rd, 04, 7:08 AM
Poorly.... typical smogger casting

novadude
May 3rd, 04, 8:55 AM
Years ago, Ligenfelter said that these castings and 441 heads were some of the best smogger castings. However, as RB said, the best crap is still crap! smile.gif

Junkyard Dawg
May 3rd, 04, 10:28 AM
Originally posted by novadude:
Years ago, Ligenfelter said that these castings and 441 heads were some of the best smogger castings. However, as RB said, the best crap is still crap! smile.gif What about 882 heads? They're worse than 993's.

I always thought 441's were a pretty decent flowing head? The only bad part is they're an open chamber head. graemlins/sad.gif