LSX 454 crate engine tune help

Just dropped a new LSX 454 crate engine into my 62 vette restomod. Its stock with LS7 intake/injectors. It has headers. Using E38 ECM with LS7 tune and after bumping cranking airflow and idle airflow and bumping spark to 16 from 13, it starts and idles reasonably well at 900 rpm. Using a card style MAF and all other stock sensors.
Does anyone have a tune for the LSX 454? I didn't see one in tune repository.
It presently undershoots idle, on coastdown mostly, sometimes stalling. There is also an off idle stumble. LTFTs are close to zero
I'll get it dyno tuned at some point.

Attachment 19753Attachment 19753
Thanks very much!

LSX454 TECH SPEC

Cam:
Valve Lift (in.):
0.648 intake / 0.648 exhaust
Camshaft Duration (@.050 in.):
236

Will need to correct VE/VVE and MAF tables to get it to run correctly.

What is the cam's lsa...?

Thanks for help!
LSA is 110.
Will correcting VVE and MAF tables help it idle better too? Or should I play around with idle adjustments first. It actually seems pretty stout off idle and feels like it is making good HP and torque. I had LS7 in car before this motor~500rwhp. and the 454 feels stronger. (Spun a main bearing on LS7 and decided to go w LSX)
I'm going to get it to the local dyno for a proper tune soon.
Best, dave

Usually set idle rpm higher enough to allow it to run, then do VE and MAF, and then do idle tuning.

Loadable dyno will help you more easily map out VE and MAF then on street.