So I just started getting my old cat back on the road after many years and I'm doing my best to remember all the things I did to the car 20 years ago.
Anyhow I just converted the brakes from manual to power and it turns out the motor is only pulling about 8" vacuum at idle and about 12" at 2k RPM. Power booster is basically not functioning with such low vacuum. Once I saw those numbers I remembered that's the way it was when I built it. Doh! Its hell getting old.
Well I have 2 questions. First, do you all think I can pull more vacuum based on the engine specs (I'll give them in a moment) and second, any recommendations on a 12v vacuum pump that some of you with high overlap cams might be using.
Here's the car as it sits now:
3.90 limited slip in 9" w/ 31 spline axles
small block c6 / e4od first gear / shift kit
2800 stall converter
351w bored .030 over
69 cast iron heads with extensive porting polishing and fitted with 2.02 / 1.60 valves
Torker II single plane
Eddy 750 cfm carb
msd 6t / blaster 2 coil / duraspark dizzy
Flat top cast pistons 11.5 compression
Comp cams 280h installed straight up
- Lobe separation (degrees): 110
- Intake Centerline (degrees): 106
- Valve Lash: Hydraulic
- Duration: Intake 280/Exhaust 280
- Duration @ .050" Lift: Intake 230/Exhaust 230
- Valve Lift: Intake 0.512/Exhaust 0.512
- Lobe Lift: Intake 0.32/Exhaust 0.32
Comp cams 1.6 roller tip rockers
1 5/8" full length headers
Timing is 13 initial 33 total. All in by 2500 rpm.
Don't rough me too hard on those heads, 20 years ago it was the hot set up Oh and the only other thing I've done is spray brake cleaner around the intake to make sure there were no leaks and adjust the idle mixture screws a bit. That got me from 5" to 8" of vacuum. The motor is making great power, long strip of rubber in front of the house at the moment
Any help would be greatly appreciated!
Charles
Anyhow I just converted the brakes from manual to power and it turns out the motor is only pulling about 8" vacuum at idle and about 12" at 2k RPM. Power booster is basically not functioning with such low vacuum. Once I saw those numbers I remembered that's the way it was when I built it. Doh! Its hell getting old.
Well I have 2 questions. First, do you all think I can pull more vacuum based on the engine specs (I'll give them in a moment) and second, any recommendations on a 12v vacuum pump that some of you with high overlap cams might be using.
Here's the car as it sits now:
3.90 limited slip in 9" w/ 31 spline axles
small block c6 / e4od first gear / shift kit
2800 stall converter
351w bored .030 over
69 cast iron heads with extensive porting polishing and fitted with 2.02 / 1.60 valves
Torker II single plane
Eddy 750 cfm carb
msd 6t / blaster 2 coil / duraspark dizzy
Flat top cast pistons 11.5 compression
Comp cams 280h installed straight up
- Lobe separation (degrees): 110
- Intake Centerline (degrees): 106
- Valve Lash: Hydraulic
- Duration: Intake 280/Exhaust 280
- Duration @ .050" Lift: Intake 230/Exhaust 230
- Valve Lift: Intake 0.512/Exhaust 0.512
- Lobe Lift: Intake 0.32/Exhaust 0.32
Comp cams 1.6 roller tip rockers
1 5/8" full length headers
Timing is 13 initial 33 total. All in by 2500 rpm.
Don't rough me too hard on those heads, 20 years ago it was the hot set up Oh and the only other thing I've done is spray brake cleaner around the intake to make sure there were no leaks and adjust the idle mixture screws a bit. That got me from 5" to 8" of vacuum. The motor is making great power, long strip of rubber in front of the house at the moment
Any help would be greatly appreciated!
Charles