I got the chance to have some cheap power only runs on a Rolling Road today after I messed with the jetting on the A yesterday. Since it's been on the road ( 1000 miles in 4 weeks now ) it seems to stop dead at 70 mph ( 3500 rpm) .
The rejetting I carried out feels great seat of the pants and the rolling road showed a AFR of around 13.2 , just a little rich.
The engine is an old Pinto , comp test shows 160 psi so lower end of acceptable. I've added an Injection head and High Torque cam and it also has a 4 branch and 32/36 DGAV, so on a good day in the region of 120- 125bhp at flywheel.
Stock motor is quoted a 111lbs at 3500 ...96bhp @ 5200
Mine came out at 120lbs at 2100...80.2bhp @ 3250
Now the point is that the power stops dead at 3500, drops like a stone hence the lack of any acceleration but not down to aerodynamics as I first thought? The AFR is still good after 3500 even though the power is dropping ? To me that rules out leaning out due to fuel pressure ( stock manual pump with reg set at 4psi)
The motor revs clean off load and you can hear the second choke come in ( though in top , under load , it feels like you can't ?) .
One of my thoughts is that the distributor is electronic controlled by water temp and vacuum and aimed at economy ,couple that with the reduced vacuum due to cam change could that be the issue ?
I might have to revise the jetting though, dropped from 35 to 25 mpg
Anyone like to throw their ideas in the pot ?