03-02-2004, 01:31 AM
Join Date: Mar 2000
Location: 51°N 114°W, 3500' elevation
Actually the 882 castings should be called "best of the worst". They're not that good. Stick a coat hanger into one of the center exhaust ports. It should come out the heat risor on the other side. If you can stick a coat hanger into both center exhaust ports and they both come out the other side you have some boat anchors. The casting is so thin in that area that the heads are usually always cracked.
"202" heads refers to the intake valve size. Back in the late 60's and very early 70's GM produced some performance heads and used large 2.02/1.60 valves. Compared to what was available at the time these had very good performance potential. By today's standards with all the aftermarket heads available, the old castings are thin, outdated, restrictive and expensive to upgrade.
76cc is considered large chamber smog heads. Compression can be bumped up using a dome piston but there's better 76cc castings available. 992 and 993 are some of the better ones. The nice thing about large chamber heads is that the valves are unshrouded.
All the old production heads use small diameter valve springs. Valve lift should be limited to .480" unless a lot of machine work is done to the heads. The old performance heads are usually before 1969. In 1969 GM started mounting accessories onto the heads and the older heads don't have accessory bolt hols in the ends of them.
I had some 64cc, 2.02/1.60 heads worked over on my old 383. They were 370 castings (replacements for the 492) .I was able to run very high 11's at 117 mph. For what I invested in the heads it would have been cheaper to just buy an aftermarket set.
Follow my racing progress or check out the car on http://www.hardtail.com
87 IROC ET Bracket race car 540 alcohol big block
Best ET and MPH on a time slip: 9.348 @ 144.13
Best 60 foot: 1.293
Last edited by Stephen 87 IROC; 03-02-2004 at 01:39 AM.