I admire the effort, and the end result isn't terrible at all. I was going to do the same, faced with the same dual 2.5" into a 3" single on my Blazer. I found this at Summit for just under $30 though and hit the easy button instead.
You'd think even with too small injectors it'd still be able to do more than idle. No load rev doesn't take much fuel at all.
What does it do if you try to rev it?
Just stalls out. I may need to recheck the timing and data log it. For some reason I wasn't able to get any sensor data to read.
Did you get any numbers at all? like fuel pressure? I'm wondering if maybe a pinched fuel line somewhere hindering supply so much that idle is all you can get?