Is anyone running a low deck with Trick Flow heads and a Progression Ignition distributor? If so, what valve covers are you running that will clear it? I have Summit cast valve covers on mine to clear the MSD distributor I had in it. It seems like the rail is too thick on these covers. I don't know that I can grind the rail without going all the way to the head. Picture is of the covers.

I'm running an RB. The Progession Ignition distributor is taller than the MSD Pro-billet unit. If your MSD Pro-billet fit, so will the Progression dizzy.

But it doesn't. It's also wider than a Pro-Billet. I don't have a picture, but I'll take one. It hits the rail of the valve cover and won't draw into the block. I pulled it in a couple threads and you can't turn the distributor for the original adjustment, or remove the valve cover.

I've had to grind more than one cast aluminum valve cover on the rails to clear the distributors like the later style MSD and Holley hyper spark distributors
Same thing on some of the imported cast and polished , some fabricated brands also, aluminum BB valve covers with the wide gasket rails on the inside to clear the corner roller rocker arms

Like Cab says, I had to grind the rail of the valve cover to clear my MSD. It didn't take much, but it was a long time ago and his post jogged my memory.

It appears I will have to grind more than a bit of valve cover to get it to fit. $530 and it is that far off. Very disappointing.

I've used tall deck distributors with adapters to low decks, that raises the main distributor body up above the low deck valve cover rails
Lots of ways to lick the problem

I thought of that. But I'm another week out from getting where I would have liked to be a week ago if the part fit. I realize it's the way things go, but I was excited to dial this thing in.

Start welding... you can fix that up in a short time,, weld up the inside edge of the head

This, and/or consider grinding the distributor body to help gain the clearance.