Which valves/springs for my 360?

'66Cuda said

TMM- I get it. I do appreciate your advice. Admittedly, this IS my first time reworking heads like this. My thought was to get the parts I wanted and take them to the machine shop, so I know what I am getting.

I have thought of taking the valve springs from the smog heads and putting them in my J heads. I just wasn't sure that he had replaced those along with the cam. I may just have to drop them off bare and let the machinist do his thing. I am sure it will make him happier. In that case are the expensive valves worth it on a mostly street 350-375 hp application?

Thanks

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All the stock springs I've seen on 70's smog heads were a fairly small diameter. Most standard design aftermarket springs are in the area of 1.43" o.d. or larger. You can also verify if their correct (and good) by testing them. If you don't want to buy a spring pressure tester your machinist should be able to do it for you.

Good designed valves can aid in air flow. I learned that several yrs back when I swapped stock valves for a set of REV valves in a set of X heads. The numbers jumped up 15-20 cfm across the board without doing anything else. They also lowered the chamber volume 4 cc's which raised the compression ratio. For 350-375 hp you don't need 2.02 valves if the bowls and ports are prepped right. Since you say this is your first go around read up real good on what works and what doesn't so you don't do a bunch of work and end up with a pair of boat anchors. I have seen guys do that. A pretty port doesn't always mean an efficient port.