pearlpurple

Has anyone got any pics of the generation one small block Chevy 202 heads.

I have a 350 small block that I am rebuilding for my truck and I was talking to a guy who says I may have 202 heads which are good for a bit more power and better gas economy. I have no idea and I can't see any casting numbers on them. What makes them better??

The heads look like basic chevy heads with what is like a double valve springs. The outer spring is normal but the internal spring is a flat spring, the valve seals are the o ring type on the shaft of the valve.

The engine came out of a 3/4 ton 78/79 Chevy truck and it has a two bolt main crank.

If anyone has any pics of what 202 heads or a link that specifically shows what they look like I would appreciate knowing.

Thanks for any help.

pearlpurple

I finally found through the search function a very good link.

My heads are not 202's.

http://www.angelfire.com/tx5/randysr...Headguide.html

which indicates to me that they are:

Large chamber (76cc), hardened exhaust valve seats, compromised intake port(‘71-’76 350/400cid), best of lightweight heads casting number 882.

I measured the intake valve at 1.94" and the exhaust valve at 1.5"

Since I have identified them can some one with good head knowledge put this into perspective for me, are these good heads, what kind of HP (potential) can I expect (ballpark) ??

76 c.c. is that good??

Any help form those with more knowledge than me is most appreciated.

transxtreme

Get some higher compression pistons for the larger chambers, if you want to make more power.

Stephen 87 IROC

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 By today's standards with all the aftermarket heads available, the old castings are thin, outdated, restrictive and expensive to upgrade.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.

menlatin

true dat. With the money and time i put into my 441's, ($800, + 70 hrs or tweaking/porting), i could have bought some BADA$$ aftermarket heads.

pearlpurple

thnx for the replies