Something to do with the hydraulic handbrake master cylinder? A pressure residual valve in that?

Check the float level. The chamber breather is on the front face above one of the throats if the float level is too high it might be causing a bit of a weep. Not sure if the return spring would be causing much of a problem.

Pretty sure this car was built by Alan Pitt, don't think Steve ever had it.

While you've got it apart check all the clearances between the underside of the valve spring retainer and the top of the guide or stem seal. With a larger cam plus the head has probably been recoed at some stage (varying length of guides), things could be getting close under there.

The only time I've ever bent an A series push rod is through complete user error ie putting a motor back together in a hurry and not backing off all the tappets before turning it over. My fault not the Datsun's.

Slim chance it could be a 411 Bluebird.

Just in case its not been made clear, the weight of the SU oil is not a "set and forget" item, it's an element of your overall tune. It primarily affects the rate of enrichment under acceleration, and works in conjunction with the dashpot springs. Some experimentation can pay peformance divideneds.

Daveman I think he did a 60sec run. Not sure how competitive their day was, it was more a social event for their series sponsors, supporters etc. The way its setup is probaly not ideal for hillclimbs. Last year they had the day at Morwell and I think it needed a forklift knob on the steering wheel to wind the lock on quick enough!

Looks like you had fun. A mate was there the previous weekend in his IPRA Torana hatch and said he had a ball. Apaprently pretty tricky in a 500+ HP car on skinny IP tyres! I see you've got Firebase on the car, when I get the next variation from Jake at least I know it will be supporting a Datto!

This is great stuff guys - keep it coming.

A couple of other things to keep in mind or consider:

One. Even though we talk about front and rear ends, it always has to be remebered that both ends of the car happen to be linked by a supposededly solid structure ie the chassis! Anything done to either end affects the opposite end.
Two. Further to the comments about roll centre heights, it is very easy to end up with a low front roll centre when lowering excessivley without some type of correction. Once the outer end of the control arms are level or higher than the inners, its time to do some research. This combined with the relatively high rear roll centre of a leaf-sprung rear end (with no additional lateral location devices) can result in a roll axis making a dive toweards the front of the car.
Three. Excessive front roll stiffness can cause the inside wheel lifting scenario (worse if the bar doesn't have enough droop travel as noted in a previous post). However, this is a compromise sometimes needed if competing with an open diff, to try and keep the inside rear on the ground & yet still try to limit the over-all roll to an acceptable limit.

some of the l-series motors that the importers used to bring in (API and the like) came with EFI manifolds that they coudn't give away. May be worth trying to chase one up, it would make your initial set up heaps easier.