Hi Guys, Ran into a problem which I'm sure has been covered before but I couldn't turn anything up via the search. Ok here is the skinny, I purchased some 4.5 PV's from Holley and they wont fit the 94 in a couple of ways. First and perhapes most importantly, the brass retaining nut at the top of the valve wont clear the channel. The stock part is narrower at the nut and spring. The second issue is the stepped area where the gasket sits and the radiused area close to the stem. I can lathe these off but have no idea how to address the brass nut issue. I guess I have two options: one is the take a die grinder to the channel and open it up enough for modern PVs to fit (risky?) or find a source for PV's that will fit 94's AND are available in 4.5's. Can anyone help with either a supplier or some info? Danny The stock is on the left, the replacements on the right. There is a few differences, the spring and brass retainer are narrower on the stock compared to the replacement, the seal surface is flat and there is no radius where it meets the stem and the overall height is less The stock is on the top, you can see the difference in the width of the stock Vs replacement. The who spring assembly on the stock actually sits inside the stem. This is the stock PV sitting up inside the bowl. It just clears the channel (about 1cm inside the channel there is a step) Here the replacement's brass retainer hits the step.