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I need some suggestions of what to try next on my 74 260Z that starts fine but has little to NO power on the road. I have working on fixing the issue for 10 solid days and have ran out of ideas. Quick history - I finished restoring and finally started the car on Dec 14. The first drive was 12/23/11 and she did great. Drove her almost 400 miles over a few days without incident. Plenty of power and fun as hell to drive. Only twice in the first week did she kinda studder on take-off. Didn't think much of it until on New Year's day she almost stranded us 30 miles from home. Started making a different engine sound (a "bauhhhh" ipo a "brrrhhh") and sputtering real bad. Gimped home at 40mph and much slower going up hills but made it home. After 10 days of trying any and everything I think it could be, exactly same as it was. I need some new suggestions. She starts fine. Idles OK even though the RPM's fluctuate some. Just zero power. Here's what I've tried: Fuel: 1. New filter near mech FP, new filter near elec FP, neither were real dirty but replaced anyway. 2. Confirmed power to elec FP while running w/ test light wired into trunk, getting 12V. 3. Re-tore carbs apart. Yes they are flat-tops. Front carb bowl was kinda dirty with rust-colored debris. Rear was clean. Rechecked float heights and installed new diaphragms/gaskets on both power valves. I had put a new kit (needle/seat and other gaskets during restoration but failed to do power valves. 4. Removed fuel lines and blew them out. Checked with empty Mason jar that I'm getting plenty of gas when starting and running. I haven't hooked up a pressure gauge in-line yet as some have suggested. 5. Removed and cleaned all spark plugs. Front 3 were dirty and appeared to be wet or fuel fouled. Ran same after reinstallation of clean plugs. 6. Checked both sides of exhaust manifold after running awhile (ouch) and both sides were hot. 7 Disconnect charcoal cannister and cracked fuel cap for venting. Ran the exact same. 8. Ran with mech FP removed from series but ran about the same. Began thinking electrical at this point. Electrical: 1. Coil is a Crane PS20 and is seeing 12V while running. Replaced with the old coil and ran the same way. 2. I am going to check the air gaps in the dizzy today and run a test on vacuum advance that many posts mention but was hoping someone else had other ideas. Before we start a whole series of "boat-anchor" discussion about the flat-tops, I personally think its something else. She ran great for 400 miles first and the weather here is cool and not causing vapor-locking. I do not run coolant to the flat-tops per suggestions that overheating can occur. Anticipated thanks.