low rpm shake diagnosis

[mat in tn]

yes they use a specific plug. but haven't we all seen where somebody changed something. if the thread is 1/8' npt then you might have a hollow base brass hex head plug which weighs one amount but then someone could easily thread in an 1/8" solid steel one weighing more without considering the balance.

[85lebaront2]

This is exactly why the heavy spot needs to be found.

[mat in tn]

today i had a chance to tune the truck a little and review a bit more before determining whether it's a dynamic shake from set up or an external balance issue. the owner wanted to cover the bases before going too deep. so, we removed the upper intake and went through the valve lash setup to double check his work. this turned out to be a perfect example of "don't change too much at one time". too many adverse effects. the rockers are comp cams magnum roller tip on 3/8 studs. it seemed to me that the adjustments were way to troublesome. same basic thing as the sbc and early sbf rockers. not sure how these are so finicky. either way it was easy to see how he had them so far off. i found a few very tight yet they are noisy as hell. anyway, now it runs better but the shake has not changed. he feels better knowing we have double checked all of that and we will see what he chooses to do from here. indexing the torque converter may be the next step. possibly three times.