Trouble with timing

[craigerdesigns]

My timing continues to go down as my engine revs up. It is 38 at idle 34 at 3000 32 at 4000.
The engine is a stock 350 with very mild cam stock hei distributor with the advance welded and vacuum removed.
I have tried the ignition module, coil and distributor gear. Any ideas?

[ToddSmith16]

Have you tried different timing lights and they all do the same thing?

[speedbuggy]

Have you checked the distributor shaft endplay? Should be around .008-.010. This will cause timing to retard as rpm goes up (although 6 degrees seems like a lot). You can get shim kits for it.

[Driver50x]

Have you checked the amount of play in the timing chain? The timing will always retard a little bit as you rev it up due to the timing chain stretching, but six degrees is too much.

[craigerdesigns]

I have shimmed the distributor, and two different timing lights. I do not know on the timing chain. I have put a wrench on the crank and it doesn't seem like much play but I do not know how much it should have. I was leaning toward changing timing chain but it only has 15 nights on it. Thanks for the help. Any other ideas before I tear down the front of my engine?

[billy5]

sounds crazy i know...but...i had a flat tappet hydraulic cam engine that i installed a high pressure oil pump in and it started doing the same thing with oil pressure close to 80 psi....was told the resistance of the pump plus the added pressure being pushed into the engine and against the rear of the cam was forcing the cam forward....installed a cam button and it got better but watched the timing chain cover flex out with rpm and oil pressure increase..so i made a bracket and welded it to the cover on the back of the waterpump where i could run a [jackbolt] against the timing chain cover as close to the cam centerline as i could get it...now it only retards 2-3 degrs and that seems normal for a module and slack in all the gears and chain..not sure if thats your problem,but it was deffenitly mine.

[craigerdesigns]

seems like the problem was in the distributor shimming. I played with it more and now it only moves 3 deg from idle to 4000rpm, and nothing between 3 and 4000rpm