[76CHEVC10]

1976 350, 4 barrel, very low original miles 67k. heres the problem.when accelerating moderately hard as when pulling a trailer up hills. valve chatter, same thing when in passing gear on highway. does it when accelerating hard from a dead stop. primarily at top of rpm cycle before the gears change. runs great during city driving and just normal driving around. where do i start on this one?????

[Max Keith]

That sounds to me more like detonation rather than lifter noise, from the condition you are describing. What is your initial advance on your distributor? Try backing off the distributor about 2 degrees and see what happens. If you have a timing light, try setting your initial advance at 10 degrees. Set this with the vacuum advance disconnected and the vacuum line to the carb plugged.
Other questions: Do you know what your compression ratio is? What octane fuel are you running?

If you had a situation of bad lifters that would clatter, that would be a constant noise, and if thats the case, it sounds like time to replace them.

Have you worked on the valve train any lately?

[Siggy_Freud]

I agree about the detonation situation. In both instances you are putting the car under a hard load.

Start by getting the highest octane gas you can at your station. And dont go to the same station you went to last time. Make sure your tank is nice and empty before filling .

[85 vette]

Originally posted by Siggy_Freud


I agree about the detonation situation. In both instances you are putting the car under a hard load.

Start by getting the highest octane gas you can at your station. And dont go to the same station you went to last time. Make sure your tank is nice and empty before filling .

I agree with Siggy( you're such a smart kid.) and try throwing an octane booster in with a fresh tank of gas.

[Siggy_Freud]

lol well technically I just said what Max said in a different way. I think he deserves any credit for this post .

[Max Keith]

Thank you Siggy, but you did cover the part I left out so guess we can just pat each other on the back, OK?

[76CHEVC10]

Timing was 4 degrees high, backed that down. 93 octane in tank with Outlaw octane booster. Guess what no chatter. Thanks Guys!

[Siggy_Freud]

Awesome. I am so glad when people post saying what the fix was and how its running now .