The 330 crank has a manual trans bushing, it protrudes slightly. I wondering if it is interfering with the converter pilot. Pretty sure it is fully seated, can't fit a finger between the converter and the case on the pump side. There is a gap between the converter and flex plate. Any thoughts?

 

Since the transmission has to come out, confirm that the converter is seated. Before removing the transmission note the distance between the converter and the bell/pump area. The converter has to jump back toward the tailshaft two times while rotating it. After it jumps back twice compare the bell/pump distance again, if it's the same the crank bushing is likely the interference. If the distance is less the converter wasn't seated.

 

I found this in another thread by oddball.
Well, this is interesting.
Bore on a 330 crank: ~1.68"
Bore on a new SBO stroker crank: ~1.71"
Snout on a PATC 200-4r converter: ~1.70"
That is my converter, so it looks like clearancing is in order. Not an easy task with the headers, dropping back down.

 

If there is a gap between the torque converter and the flexplate, I'd remove the pilot bushing.

 

I considered it. I am pretty sure the issue over all diameter but will remove a little bit off the hub. Yes the converter is not touching the flexplate, the usual gap.

 

The converter should be flush with the flex plate when it’s pushed forward.

 

If it isn't already, chamfer the leading edge of the converter nub. Sometimes those bushings come out easily if you pack them with grease, put a tapered punch in the center hole that fills the hole and then strike the punch. And....sometimes they don't.

 

I was looking into flex plate runout on a SBC, came across this. Seemed remotely relevant.

Beware of the Bushing
Virtually everything on the problem pickup had been checked and double-checked and a variety of shims had been tried, all without success. With the starter removed once more it was obvious the ring gear on the flexplate was damaged and would have to be replaced. Assuming a faulty flexplate was the source of the problem the engine was removed, at which time the real issue became obvious. There was a pilot bushing in the end of the crankshaft for a manual transmission that had been overlooked during the initial engine installation that should have been removed. The bushing kept the torque converter from seating in the crankshaft properly and when the converter bolts were tightened the flexplate was distorted, creating a mismatch in the gears that could not be corrected. Removing the bushing and installing a new flexplate solved the problem.

The lesson learned here is that some GM Goodwrench engines come with a pilot bushing in place that must be removed if an automatic transmission is used—and you want a quiet Chevy starter.

​​​​​​….

 

I am seriously wanting to go manual at some point, that is why I left the bushing in. I am going lower it enough to hit that converter snout with the angle grinder, remove a good amount. I assume fluid is no where near it? Then a quick around the outside just make sure of the diameter. I always have gaps between the flexplate and converter on install, I usually put at least one washer to not allow the converter to pull too far forward. I didn't do that on an Oregon Performance 2004R converter, it hemorrhaged trans fluid. It must just be contacting the pilot bushing. I can fully tighten it on one side of the bell housing and can spin it until the other side is nearly tight. I noticed the TH350 snout oil shallower and angled slightly, would probably clear.

 

Pack the crank/pilot bushing hole with grease and then tap a clutch line up tool into the hole. It will push the pilot bearing out without damaging it if you want to reuse it later.

 

I decided to clearance the round end right off. You could see slight contact at the front edge, a tiny bit larger, clearance that as well. You can see it in this picture, no longer there and turns with no resistance. I didn't want to have to fight the bushing out.