Tweaking 1275 post rebuild

[moggiegeek]

Hi, Happy Xmas to all.
I've had the joy of doing some longer "running in" journeys and it's raised a few questions.
The engine is a rebuilt 1275 with 266 camshaft, Minispares Stage 3 head, maniflow inlet and lcb exhaust, with K and N filter. It's currently on a HIF38 carb with AAA needle.
I attach photo of plug following a couple of decent runs.

IMG_20231226_153804.jpg (1.48 MiB) Viewed 3346 times

The engine starts very easily, no choke however last few days have been warm.
In working through the gears I notice a very marked loss of power on uphill inclines, in 4th speed drops and engine fades. Drop down a gear and blip the throttle and it picks up smartly.
A. I'm wondering about whether with a 266 cam I'm not using it's power band well. Basically should I be using more revs in lower gear. If so, what should rev range be?
B. Is the carb running too rich at starting and too lean thereafter
C. With this set up should I really use an HIF 44 as engine is running out of breath. If so - and I do have one - what needle would you recommend as a reasonable starting point?

[Sleeper]

C Yes BDL needle.

John ;-)

[moggiegeek]

Thanks for recommending the HIF44 and starting point BDL needle for starting to set up. Can you shed a bit of light on the other wonderings?

[Sleeper]

" A. I'm wondering about whether with a 266 cam I'm not using it's power band well. Basically should I be using more revs in lower gear. If so, what should rev range be?
B. Is the carb running too rich at starting and too lean thereafter "

Sorry,
A .know nothing about 266 cam/timing/performance ,
B. The plugs look quite lean , should be a little rich at starting/tickover.

John ;-)

[ampwhu]

From my experience, i use a Hif38 on a 1098 engine and a Hif44 on a 1275 engine. Both run lovely.