What year 350 chevy heads are prone to cracking?

[348tripower]

I know this has been discussed befor, but can anybody tell me which ones to avoid?
Thanks,
Don

[1FATGMC]

I know this has been discussed befor, but can anybody tell me which ones to avoid?
Thanks,
Don

You are in luck, I read the answer to your question just a couple hours ago while sitting on the throne and finally getting around to reading the February 2002 issue of Hot Rod.  I got a little behind in my reading while building the house.

According to their "35 YEARS OF THE 350" article:

1974:  Chevy substitutes lighter, thinner head castings on most production small-block applications in an attempt to reduce vehicle mass for improved fuel ecomomy.  These '74-up heads are more prone to cracking, have less material left after radical porting, and should be avoided.

c ya, Sum

[purplepickup]

1974:  Chevy substitutes lighter, thinner head castings on most production small-block applications .......
c ya, Sum

Did they say anything about a particular casting number?

[model a vette]

I don't know all the casting numbers (one is 376450) but I believe the heads in question were the first ones with the additional bolt hole for the exhaust manifold. That would mean that the head would have seven bolt holes rather than the earlier, traditional, 6 bolt holes. These were originally developed for the small cu. in. SBC, i.e. 267, 262, 305, to be used in smaller cars for better gas mileage.

[1FATGMC]

Did they say anything about a particular casting number?

Sorry, but they didn't,

Sum

[Pope Downunder]

I know this has been discussed befor, but can anybody tell me which ones to avoid?
Thanks,
Don

Check these sites for info;
http://www.chevytalk.com/tech/engine/SBC_Heads.html
http://www.angelfire.com/tx5/randysresume/Headguide.html