i have the s/r 1.94/1.50 heads that i am gonna put on my 350 and i am wondering wut getting heads ported usually runs? also are these the same heads as the 2.02 s/r's if i were to get the 2.02 valves put in? thanks

 

With the reduced chamber sizes of the 305 heads, you may not have the best flowing design for the 350. The intake and exhaust are hampered by shrouding, and the cost of having the 305 heads machined for larger valves AND the unshrouding may exceed the cost of good replacement 350 heads. Considering that bowl porting and some runner work would be necessary to really get deecent flow to feed a 350, you may be wasting your time and money.

Perhaps you should offer up the 305 heads in the classifieds when they are no longer needed, then add a little cash to your proceeds and purchase better 350 heads, like Pro Action Iron Lightnin' heads.

 

there not the 305 heads they are just the s/r heads with 67cc chambers and the small valves.

 

What Vader was trying to get to was that the cost of matching these heads power wise to a different set of heads through a machine shop is going to be a waste of time and money. Just save the money and buy yourself a better head.

You could port and polish the heads and install bigger valves, but it will cost you close to or as much as a better head to begin with.

 

If these are the heads you really want to run, then installing 2.02/1.60 (or even 2.05/160) valves can pick up some flow for you. If they are like the World heads that I have seen, you will do yourself a lot of good just by opening the valve bowls of the restrictive areas as cast. They certainly could have spent a little more time with their molds to get the ports fitting the valves better.

If you are going to pay for someone to do the work, it may not be worth it. If you have the tools and time, go for it. Match the ports and runners at the gasket surfaces, especially at the exhaust side. Blend teh larger bowls to the runners, and cut down the short radius on the exhaust side. You should also trim the valve guide bosses at least on the port sides and polish the exhaust bowl runners as best you can. A light polish in the chamber would be beneeficial as well.