Need Help, 225 With Hei No Spark

The new chugging sound may indicate the timing is close but not perfect, at least on some cylinders.
Pull one or two plugs immediately after cranking. Make sure those exhibit a trace amount of fuel. They should smell like gas. If this test checks good, then I suspect a timing issue.
If this test fails, then pull a valve cover and make sure the valve train is functioning.

 

Yes. But after all this, are we sure it is not a flooding problem? "New Carb."

At this point I'd probably make sure all the cylinders and plugs are totally dried out, wedge the carb and choke wide open, then try a spritz of starting fluid while cranking. At least see if it can fire.

 

I'm also wondering if you have the correct distributor.
What donor vehicle are you using for the odd-fire? The 1975, 1976 & some 1977 Buick Apollo, Century and Skylark should be valid donors.
Make sure your FLAPS understand the odd-fire application.
Make sure it matches the descriptions for odd-fire at this site. HEI's EXPOSED (toast.net) Specifically, the cap has odd spaced terminals & 3 sizes of tang inside, the pick-up has odd spaced points and the high voltage coil should have red, black and white (not yellow) wires.

 

Thanks for the tips! I pulled all the plugs last night when I re-checked for TDC on compression and they were dry but did smell like fuel. I did wonder about the choke last night not opening, I don't have the electric choke wired yet so I wedged it open. I plan to hit it with starting fluid today and see if that makes a difference.

The distributor is one of the CRT units found on ebay for the 225. When ordering new coil and ignition module I asked for 1975 Skylark parts. Interesting about the wire colors - the CRT coil had red, yellow, and black while the new Napa coil has red, white, and black. The cap is definitely odd fire with the combination of long and short tangs underneath and offset terminals.

I'll pull valve covers today if the starting fluid doesn't make a difference.