302 heads

The 302's and 308's are almost as bad as the stock magnum heads for cracking. As far as something you can see, sometimes it is, sometimes it isn't. On a set of used, dirty heads you're only going to see the really bad cracks. I managed to get a set of 308's that were in good shape, but not all of them are.

What are your plans for the 302's?

I ask because the 302's are good for bolting on some compression on an otherwise mostly stock 318, but if you're planning on a higher horsepower build you'd probably be better off getting a new set of heads. The 302's have the same 1.78/1.50 valves as every other 318 head out there, as well as the small 318 ports. They do have a better exhaust port than the earlier 318 heads. So, I think they're a great head if you just want to get a little more out of a stock 318, they bump up the compression almost a full point and flow a smidge better. So, for example, if you're trying to warm up a stock 318 with a 4 barrel and headers but don't want to do a full rebuild, the 302's are a great deal, just bolt them on and go.

But, if you're planning on a full rebuild, and want to throw in larger valves, a bigger cam, etc, I don't think the 302's are the way to go, and I'll explain. I have a set of 308's on the 340 in my Duster. It's a '68 340, so the pistons stick out of the bores .018". Because of that I wanted to stay open chamber, which limited my aftermarket options for heads. So, I bought a set of 308's, had 2.02/1.60 valves put in them, had them cut for dual springs and positive seals, had them trued up, and had them ported. End result was that they flow 264 cfm @ .500", which is pretty decent. But, after all of that and the cost of buying the heads to start off with, I had spent enough money to buy a set of Edelbrock 340 heads. Granted, my heads flow a bit better than out of the box Eddy's, but not a heck of a lot.

With the price of heads like the EQ's or Indy LA-X heads, it doesn't make a ton of sense to be doing much work on a set of 302's. I bought a set of the RHS Indy heads for the 318 in my '71 EL5 Gt. Out of the box with 1.92/1.62 valves they flow 246 cfm @ .500". Compare that to a stock 308, which flows around 200 cfm @ .500". And that's significantly more than the stock 302's will flow with the small valves. At the time, I think I paid about $1,300 for the RHS LA-X heads. If you take a set of 302's and open up the valves, buy all new hardware, have them cut for dual springs, checked for cracks, valve job, guides, seals, etc, plus the price of buying the heads, I think you'll have a very hard time staying under that number.