Car is a 71 240Z with a 2.6 from a 260Z. SU carbs are from the 240. The car pulls away and make great power in 1st and 2nd gear until 2500 RPM, 3rd gear it makes power until 2300 RPM. Anything above that and its like someone let off the throttle, its just stops pulling. All plugs are the normal golden brown. Front carbs were slightly rich when I first received the car but I adjusted them. About 1/6 of a turn fixed that problem. Car has the points rebuilt when the engine was dropped in. I thinking it might be a fuel pressure problem but I dont have a gauge. Just though I would query you guys before I go buy a gauge.

Thanks

Ryan

Why the difference in the previous 4500 rpm & the later 3500 rpm. Was the difference caused by creeping the rpms up on the 4500 & stabbing the throttle on the 3500? Also, did pulling on the choke make any difference? Mechanical pumps alone will supply plenty of fuel for round top carbs on a L26 if the filters are maintained.

Channeling Occam (actually William - I had to look it up) and Einstein and KISS - are you sure that the throttle blade is opening completely? It's called a throttle for a reason.

Why the difference in the previous 4500 rpm & the later 3500 rpm. Was the difference caused by creeping the rpms up on the 4500 & stabbing the throttle on the 3500? Also, did pulling on the choke make any difference? Mechanical pumps alone will supply plenty of fuel for round top carbs on a L26 if the filters are maintained.

Typo sorry. Mac rpm is 3500. I did not get to try the choke, we had a bad storm so the Z stayed in the Garage. Fuel filter is new and clear.

Channeling Occam (actually William - I had to look it up) and Einstein and KISS - are you sure that the throttle blade is opening completely? It's called a throttle for a reason.

Yes opening completely