[burnt_rubber]

I have a 85 351 H.O and it doesnt run right. It runs rough and doesnt keep a steady idle. At about 2-3 thousand rpm it makes a whistling sound almost like a carb spacer but it doesnt have one. I recently put a new valve spring in it because it was broken. It never did run right since i bought it. I messed around with the timing some and it runs slightly better. How do u time it correctly with the motor that cant keep an idle? Any help?

 

[BigBroncoXLT]

whistling sound could be a vacuum leak, which would also explain why it doesn't want to idle. Check for a broken or loose hose.