I have had my current 71 for 10 years. I swapped the automatic for a 5 speed about 5 years ago and swapped the engine to a p79 2.8 about 5 months ago. I clean-up the head and had a valve job done (shaved about 2 thousands) otherwise stock. It had decent power when installed. 2 weeks ago I did a cap, rotor and plugs and now it has no power under anything but about 1/8th throttle. Here are the stats:
P79 w/ new z-therapy carbs (sm needles) - decent in car tune
running a stock mechanical fuel pump
using a zx e12-80 distributor - blaster 2 coil
MSA 2.5 inch exhaust (fairly new)
compression is 180-185 across all 6
16-17 vacuum at idle
fuel is 2.8 psi at idle around 3.1 at higher revs.
So far, I think I have done the obvious.
swapped back the old plugs (all were ngk's) new ones gapped at .045
swapped back old cap & rotor
got a new wire set
swapped the fuel filter
adjusted the valves
swapped in my back-up distributor w/different module
None of these things made any difference. The plugs look ok, one had carbon deposits. Cleaned them and verified spark.
I am not sure what to do next, any suggestions would be greatly appreciated.
thanks