Spark but no start

[Profittakr]

I have a Thunderbolt IV on a 5.7L engine. This is a repower and I cannot get the engine to start. I have chased what I believed to be wiring/ignition issues and now have resolved and I have confirmed spark at the spark plugs but a no start condition. There is not even the hint that the plugs are firing. I have gas in the tank and can see fuel spraying into professionally rebuilt Rochester 4bbl carb. I have NOT checked the spark strength but do see a spark. Could I just have a weak spark and need a new coil? Can bad grounds cause this. Ignition interrupt and tacho wire are also disconnected FYI. I have also switched out the distributor with another known good one with the same results. I have rechecked that I installed the distributor at TDC and #1 cylinder so I THINK the timing should be close enough to at least fire or burb. I assume that since I have a spark at the spark plug wires that the TB IV module is still working. Looking for any help or places to look.

 

[achris]

At #1 isn't good enough. It has to be at #1 on the firing stroke. In a 4 cycle engine, the piston comes to the top of the cylinder twice in each cycle. You need to be sure, absolutely sure, you are delivering spark to the cylinder on the compression stroke, not the end of the exhaust stroke....

Chris...

 

[Profittakr]

Thanks Chris, I know that and had timed to that (or so I thought). I have resolved it however. I timed it by watching the #1 intake close and then rotate until TDC on harmonic balancer is at TDC. Then I aligned the rotor with #1 on the cap and figured that was good. Somehow, this resulted in me timing the distributor about 90* off from where it was supposed to be. I retimed it again by pulling #1 plug and waiting for compression, then TDC on balancer. Doing it this way I got is close enough to start although I was still at about 10* After TDC and needed to retard it to 8* before TDC but none-the-less It is started and ran great.
Thanks for the assistance Chris. I respect your input and reference your Youtube videos often. Keep it up, you are helping lots of people.