Hard to start,

[Donut]

I'm a little stumped here,

It seems most of the starter problems I've run across (real life and google search) have to do with a grinding starter.  My problem is more like a "hammering"

When the truck is stone cold, it will only occasionally do it, when it's warm it's a 50/50 shot it will start with no problems.  When I crank it, it acts like there is to much initial timing.  Hence the hammering.  I will see a puff of smoke out the carb and the truck acts like it's hydro locked.  If it will crank over a couple of times it will start fine.

History of the engine is unknown, the cam is mild if not stock,  compression is unknown, however I don't hear any knocking or pinging on pump gas.  Headers and an Edelbrock  intake were on it when I bought it.  (along with 882 smog heads).  I do have a little off idle stumble, but I believe it's carb related.
I've tried 2 different batteries, baked 1 starter already, and swapped the old HEI that was in there before.  Battery cables are all new. Block, frame, firewall, and rad support are all well grounded.  I carefully inspected the factory harness for any nicks and breaks.  The timing I really don't know where it is at because the timing marks are off.  When I initially set it, I brought no 1 cyl to TDC and went from there.  (repeated when I changed the HEI)  Timing was set by a vacuum gauge (17" is the best I can get)  and ear (and SOP).  I have tried to retard the timing, but to no avail.  The starter also has a heat shield, and the cables are routed to avoid the headers.

The truck cranks fine if I disconnect power to the HEI. (hot or cold)  What I've done is rig a toggle switch to the HEI power, get it cranking, flip the power "on", it fires right up.  (LOL, NASCAR plow truck)  This isn't right though, and I'm just about out of ideas and need the combined brains here.  I might be overlooking something very simple.  If it's something internal (engine) it's gonna have to wait until spring.  (after "mud season")

Sorry for the "book", but I wanted to be thorough.

BTW, could it be cam timing?  I do remember it used to be popular to advance the cam 4 deg.  (see I'm grasping at straws

[VileZambonie]

Don't overthink it. Put an amp clamp around the B+ cable, disable the coil & crank the engine. Monitor the cranking voltage and current draw. Give us the results and we can determine the problem.

[Donut]

All I've got is a multi-meter.  It was reading 9.44v cranking.  I don't know the current draw.

[VileZambonie]

You know anyone with an amp clamp? Otherwise just stop by a garage and ask them if they can test it for you real quick. Even an old school VAT-40 will tell you in about 30 seconds worth of work what your current draw is.

[Donut]

Cool, thanks.  I'll give it a shot tomorrow. (I have to go to a garage)

[Donut]

I thought I'd keep this updated.

Truck wouldn't go without major coaxing yesterday.  Too much in my book, pulled the starter back out and took it and the battery to the chain store where I bought them.  Both tested ok, the store manager could hear a "drag" on the starter,so he offered to replace it.  I ended up swapping the "3508" starter for the "3510" model.  (the 3510 was on z-28's and big blocks of that year)  So far,so good, we'll see if that's the ticket.

With the forecast of snow, and no shop time became an issue.  If this starter has a problem, I'll be looking for more help.

[VileZambonie]

Bench testing a starter is worthless. It's only good to make sure everything went together correctly after assembly. There has to be mechanical resistance to test it correctly. Your starter shouldn't pull more than 220 amps