that might not be the choice of the needle itself, but rather it is lifting too fast.

Try a thicker oil for the dashpot piston.

Jeg, you are good!  I think it is an AUD carb.  I'm very new to this as I just received my "Tuning the A-series engine" book this morning.  I haven't been able to figure out the exact number yet.
I took the carb apart, cleaned it and set the jet screw to 2 full turns from closed.  It seems to be running better already.  It has much better response at speed.  But it still gets bogged down when starting from a stop sign.
Thanks for all the responses.

James

Kevin,

Berlen Fuel Systems has a biased-to-fixed needle adapter sleeve (ABF 193) for the (large hole) suction chamber, just need to get the proper retaining screw to clamp the needle.  

Berlen wasn't the greatest help on this, though, so through buying an assortment, I found that the HS2/HS4 (AUC 2057) screw fits the HIF just fine, though it's a bit short on the body below the head.  

They also offer an AUD 4253 screw, 22mm long, for use with ABF193, although this screw needs the head to be reduced in height along the graduated marking and new screwdriver slot cut into it.

Yep, I've converted one of my HIF's to fixed needle.

If I recall correctly, Joe Curto also has a conversion kit available, and his includes the screw - in brass, no less.

I hate bias needles, they wear themselves & the jet. Fixed needles don't do this, if jet is aligned on assembly.
I am talking HS2 4 & 6 carbs here, not the new fangled HIF ones..!

Because your needle isn't supposed to sit straight.  

Your needle, (commonly known as a 'Biased Needle' - as opposed to a 'Straight Needle') uses a spring, AUD3306, situated on the top of the 'top hat', which biases the needle either towards the throttle plate or away from the throttle plate - depending upon which needle guide your vehicle requires.

(A hint:  needle guide p/n JZX1039 suits our cars)

I'll go on - 

This biased-needle configuration eliminates the need for centering the jet.  Jet wear is slightly increased, for sure, but carb jets should be considered normal service items anyways, so should be checked/replaced every few years regardless.

Can anyone tell me why the needle guide has a raised section on the top of it?  This seems to prevent the needle from sitting straight.

James