Try a different timing light. I've heard some of the dial back ones don't work right with hei.

 

The gear may be worn. Had that happen to me once.




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Won't necessarily make it retard but be sure the advance weights are correct as shown below. Pontiac distributors rotate CCW- opposite of the way a Chevy rotates- so sometimes the weights and center cam will get assembled 'backwards'.

 

The gear is a brand new Comp Cams poly.

Have also tried the standard steel gear while testing different dist.

Yep, clockwise rotation as this is a new build....Chevy 383

Also thinking this may be electrial issue have used jumper cables for alt ground.

The block was shot by a body man so the finish on the block is automotive finish & thick.

 

Chevy? Fooled me w/your photo and screen name into thinking you had a Pontiac.

 

Oh I do have Pontiacs but been building & tuning a383 I built for a Camaro....hope it's not cam walk...will find out today

 

Too much cam end play can cause the timing to fluctuate some but it won't retard it steadily.

Be sure to check the outer ring of the damper for being loose/debonded. Also sometimes the distributor gear roll pin will shear off allowing the gear to rotate independently on the shaft.

 

Just installed an MSD dist, box, & coil....same problem.

Gets to it's total then retreats with RPM

The dampener came with the Eagle rotating assembly & has very low use pervious to the new build & was inspected at the time of assembly being balanced.

How about valve lash?

 

Nah, valve lash wouldn't do it. Have you tried a different light?

 

3) hei's and one msd, throw that timing light out. lol


my guess is wrong timing chain..
has the block been line bored/honed??
yes the oil pressure at 3k could be just enough with the spring pressures to tighten up ALL the slack in the to long chain..
they make shorter timing chains for blocks with line honed mains.

 

don't care whom degreed the cam..
was the block aline honed on the mains??

 

Installed a cam button & problem solved

 

Is this a retro roller setup? If so, it definitely uses a button. In any event, glad you solved it.

 

Yes it was a retro