Spro, Snip I'm dealing with someone that wants to do this. Can anyone supply me with a link or something that lays out why you wouldn't want to bother doing it (besides wasting heads)? I'm just looking for a reference to give to them since I am not proficient enough to explain it all. Snip Easy enough to 'splain, if it were not for one basic problem they would bolt on. But since the bore of a 304 is much smaller than that of a 360 or a 401 due to the size of the valve when they open they smash into the top of the block. Translated, the valves won't fit. If he wants to spend the money on it he his going to have to notch the top of the bore to clear the valves. Of course once that is done the larger valve, even though it now fits will be partially shrouded so the breathing benefit gained by installing larger valves will now be partially negated by the shrouding of the valves by the now notched smaller bore. A better suggestion would be to forget about the 304 and build up a 360. You would start out with all of the good parts and then can go from there. Of course he could also spend money on the 360 heads and have the valve sets replaced and install 304 valves but what would be the benefit of that? He already has 304 valves installed on 304 heads which is what he is starting with. If the sole reason he wants to do this is to replace the bridged rockers with studded rockers that can be done by a relatively simple machining operation to the 304 heads. As some 360 heads are also bridged rockers that may have to be done to the heads he is planning to use too, but that is another story. I too have a 304 car I am working on. But that is why I spent $100.00 to buy a builder 360 engine rather than use my builder 304 engine that is running and came with the car. John _______________________________________________ AMC-List mailing list AMC-List@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list or go to http://www.amc-list.com