Just how "different" is a Aus 250 from a US 250? Cam timing

Specifically, how different is the relationship of the crank gear to the cam gear when installing a cam ground for the Aus engine in a US
engine.

I'm degreeing my cam. I'm using an adjustable crank gear set to fit a SBF that has been adapted to fit the US 250.

Initial settings had me starting w/ the dots on the cam gear/crank gear oriented in the straight up position. With that done, and after double checking the method I was using to degree the cam, I got a reading that the cam was in at a 101.25 degree C/L.

It's supposed to be 112.

The crank gear that comes with this set (and all of the adjustable SBF sets for that matter) only allow you to retard the cam 8 degrees. Which I did. Running the process again now yielded a 109.25 C/L.

Evidently, one of several things has happened:
1. We mis-oriented the cam/gear when we drilled it, and located the dowels 12 degrees off.
2. There is a slight difference in the relationship between SBF gear sets (1-2 degrees).
3. The cam grinder may have been slightly off (1-2 degrees).
4. Usage of a completely different gear set other than stock has to be accountable for at least a 1 degree discrepancy.

I'm saying all of this because IDK if there's something I'm missing here.

The process I'm following:

1. Find TDC w/ piston stop. Orient degree wheel to 0.
2. Install dial indicator. I'm using a 5" extension on my dial indicator, and I am doing this w/ the head off, referencing off of the solid, roller lifter.
3. Roll the engine over until maximum lift is achieved (in my case .316, cam card states .314.5)
4. Zero dial indicator.
5. Rotate engine counterclockwise .050 take reading from degree wheel.
6. Rotate engine clockwise until dial indicator again reads .050, take reading.
7. Add those two numbers, divide by 2, That should equal C/L.

The only thing I havent done was question why my lift at the cam was 1.5 degrees different than spec (cam has assembly lube on it)
I didn't take all of my measurements from a clockwise loading of the chain.
Maybe my dial indicator isn't exactly vertical??

All I know is I need another 3 degrees.

The crank gear has room left for a custom cut to create a 11 degree install point,..the problem is where to get that done.

I've read somewhere that you should degree the cam in the direction the engine rotates, never one way and then the other.
This ensures that you factor out any "slop" that the chain might have.

Try this method to see if you get any different readings.

When you go counter clockwise you want to go past you're .050" by .1 then clockwise back to the .050" to rule out slop. I've read that the C/L method isn't the most accurate but gives you a good starting point and that valve events should be checked @ .050" of lift or whatever the manufacturer recommends.

You should never rotate the engine backwards when degreeing the cam, it will introduce error into the mix because of chain slop, and could be where some of the discrepancy is. Since you know the max lobe lift, you just stop @.050" before you get there and take that reading and then continue rotating until you reach .050" on the other side of max lift as its closing and take that reading, but never rotate backwards. You should also go ahead and try to confirm what the rest of the timing events are to make sure your getting a corresponding proportional difference there. Since your using a dowel pin that was drilled to locate the gear that was installed after the cam was ground, I'd say that is the likely culprit, and it was just drilled in the wrong location. Keyway's and dowel pins are machined in the cams when they are still blank, that is how they are indexed in the camgrinder. Trying to re-locate a dowel accurately to the cam profile after the cam is ground is like trying to thread a sewing machine with it running. Sounds like the mark just got missed.

Yeah, I knew that reverse rotation caused an unloading of the valvetrain, that's why I was super thorough this time around.

After talking w/ 5-6 chain suppliers, none of them offer custom services. The guy at Cloyes at least offered a solution.

I reinstalled the cam using the tooth to the counterclockwise next to A8. Each tooth equates to approx 17 degrees. By doing that, I retarded the cam 17 degrees, and brought it back 8 using the A8 keyway. I managed to net a 110.5 C/L that way. I called Schneider, and told him that I could get 110.5 on A8, 113.5 on the tooth between A8, and A-6, using the A6 keyway. Each way, I was 1.5 degrees off from the "recommended" 112. After hearing my cam specs, and not liking what he heard for a supposed turbo profile cam, he had me install it at the 110.5 L/S to "lazy up" the exhaust opening profile a bit. So that's where it is.

At least you can get there from here, so that's good.