Thanks! Flange upper sprocket? No it's a simple threaded hole and hole that a dowel pin on the cast iron OE sprocket aligns itself with. The Sprintbird sprocket is one that Sprintbird Rob machines the inside of an OE sprocket open and inserts and chunk of steel with the adjustments you see there. There is no ability to adjust the cam timing, short of jumping a tooth, with the stock sprocket.
Here is an old picture of what the OE sprocket looks like.
On another forum someone was asking me about what port work I want to do to this engine and the Turbo engine. This is just pasted from that post:
They are opened up a bit and cleaned up a lot. I don't recall the exact measurements off hand but I think they were essentially gasket matched to this gasket.
(this is my cleaned up head in the photo ready to go to the port shop)
This is what the head on the engine currently looks like. No work done to the ports.
I scaled the pictures best I could and cropped them next to each other to show the difference in the chamber shape. The top head is currently the one on my engine. Basically opened up around the intake valve to unshroud it.
Hard to believe this engine looked like this when I picked it up a few years ago.
__________________
__________________________________________
"How I learned to stop worrying and love the OHC Pontiac L6"
The Silver Buick- '77 Skylark coupe w/455, SPX, MegaSquirt 3 & TKO-600 (Drag Week 2011, 2012 & 2015!)
1969 Firebird with a turbo'd Pontiac L6 controlled by a MegaSquirt 3 and backed with a microsquirt controlled 4L60e and 4.56 gears! (Drag Week 2018!)