<BLOCKQUOTE>quote:</font><HR>Originally posted by Sleeper:
Valves hitting the deck, flame travel, swirl, just a few of the problems. Not advisable to run 350 heads on a 305.<HR></BLOCKQUOTE>
If someone HAS to stay with the 305, then I will disagree --- you can use 350 heads. But I'll be specific, because you don't want to waste time/money on crummy 350 heads. You ONLY want to use good ones if you are going to the trouble of a head swap.
At least one magazine, a number of Fcar owners, and Mark Grave on the 9C1 list, that have used GM L31 Vortec heads using 1.94/1.50 stock valves, on the 305. The valve-to-piston clearance is an issue of the lift you choose, and you'd need a big cam to have this problem. The valve-to-cylinder deck issue is ok for stock diam valves and for anything but extreme lifts. I won't even attempt to explain the geometry involved.
The flame travel and swirl are largely provided by the heads, and the Vortec is designed to optimize them. The only real hiccup, if you can call it that, is that the Vortecs have a 64 cc comb chamber, so using them will cause a drop in the CR on a 305. So you can either have the heads milled to gain a smaller comb chamber volume, or eat the slight loss in CR and the few hp that go with it.
<BLOCKQUOTE>quote:</font><HR>I believe World Products makes a decent head specifically designed for the 305. Car Craft had an article on 305 build-ups a few years ago, included the sources for their parts. I think they used the World Products heads.<HR></BLOCKQUOTE>
That's probably true. So then it would boil down to (a) cost and (b) performance of the World Product 305 heads vs the L31 Vortecs. I think CHP tested BOTH of these heads in their (?) Oct '99 cylinder head flow test supplement so the flow data is available. You'd also have to factor in the cost of the Vortec-friendly intake manifold as well. FYI.