[John Milner]

I have been using a NOS set of stock style valves and Crower 68405 valve springs in my 614 heads for the past 12 years or so. The Crower springs work well with a Ram Air IV style camshaft and they set up at the same 1.7 height of stock Ram Air IV springs. I did not put hardened seats in the heads and it has had plenty of street miles on it with no issues. Hindsight, I probably should have went with a 1-piece stainless valve.

These would be a good valve 1 piece stainless valve for a street Ram Air IV head as they are the same length as the stock IV valves:
https://butlerperformance.com/i-3164...tegory:1459612

These Comp springs would work well with the IV camshaft:
https://butlerperformance.com/i-2445...tegory:1459605

I run those particular Comp 995-16 springs in another set of round port heads that are set up at 1.7. They work fine with the flat tappet camshaft and required no machining to use.

[Jay S]

From what I recall the factory installed spring height on RA4 is just over 1.8”. It takes some adjustments on the spring height to run a 1.7” spring. The 1.7” springs like the 68405 and the 995 Comps work ok though, but it usually needs a -.050” valve lock and a shim to get the seat pressure where it needs to be, that varies when the valve retainers are swapped with aftermarket versions.