If they sent it with a 200+ jet they had issues from the start. Keep taking fuel away from it to get the egt down around the 1150 mark is where it should be the most consistent, I doubt it'll be the fastest there though.
Makes complete sense to keep taking fuel away being its burning in the header causing a high egt. I'd bet you'll end up with around a 168ish jet.
Worked on a pro systems 1150 alky carb this past season it had 210 jets in it from them it was a on a 582 but was way to much jet, we backed it off to 196's I set the floats and fuel pressure and it went a tenth faster next pass. I am impressed with the gas stuff they do but not yet with the alky stuff.