383 Rocker problems

I have a 350 w/383 stroker kit with .515 intake lift and .525 exhaust lift and stock vortec heads. I just bought some roller rockers but although I asked for the 1.6 ration I recieved the 1.65 ratio. I keep adjusting the rockers and can't seem to get all the lash out or when I do, the noise returns very quickly. I have poly locks and set them everytime.

There seems to be an unusually small difference between getting the lash out and the valves not seating. I am wondering if I need to change the pushrods to a shorter length due to the change in rocker geometry?

sounds like a rocker geometry problem.

I would get with Crane and get them to send you two adjustable pushrods so you can measure the length they SHOULD be, then send off for a set.

Thanks madgrinder,

I was trying to set the rockers with the engine running but I will try to set them again and then follow your advice.

While your problem might be the wrong ratio of roller rockers you might have to modify your Vortec heads to accept a high lift cam. The Vortecs in stock form are only good to about .450 lift or so without machining the guides down for clearance.

Check with most any engine shop that caters to building race engines as the Vortecs are very popular for those classes required to use OEM engine parts.

Regards,
Gerry Dedonis

That much lift without machining spring pockets has got to be close to coil bind. Grinder is right, do the push rod lenth checker routine, and check for coil bind while you're doing it. With 1.65 instead of 1.6 rockers, your lift at the valve is greater so your geometry problem is made worse.