Jaguarjx2
NAXJA Forum User
- Location
- Joliet, Il
I have a 2000 jeep cherokee i bought with a seized engine. I built a new mainly stock engine with a block that was bored .30 over. I used a new casting 331 head and mildly ported it and assembled it with new stock valves and performance springs. I installed a comp cams 252h grind cam (68-200-4) port matched the intake and am running an earlier style header. running 4 hole injectors and a 62mm throttle body. The jeep is rolling on 33's with 4.10 gears and a AW4 trans. I have replaced cam and crank sensors and both o2's with ngk's. I have properly synced the cam sensor and am running champion plugs.
So my issue that I am trying to figure out is 1. it seems to be under powered. Driving on the highway i don't have enough torque to maintain 70 on a 4% grade unless my rpm's are above 3000.
Issue 2, my vacuum at idle is only at 14.7 in hg.
I beleive the two issues are related but I am trying to determine what i should do.
In researching I have found an old article discussing a custom grind that has a greater lift and duration on the exhaust side to overcome the "restrictive" exhaust port on the 331 head.
So if this is the source of my problem then would replacing the cam again correct my problem, or would a performance head from titan that has chevy swirl valves installed and greater flow on the intake and exhaust correct my performance.
Or is there some other issue that i am not seeing. I was hoping that someone may have some insight on my issue and possibly some experience with camming with the 331 head.
thank you
So my issue that I am trying to figure out is 1. it seems to be under powered. Driving on the highway i don't have enough torque to maintain 70 on a 4% grade unless my rpm's are above 3000.
Issue 2, my vacuum at idle is only at 14.7 in hg.
I beleive the two issues are related but I am trying to determine what i should do.
In researching I have found an old article discussing a custom grind that has a greater lift and duration on the exhaust side to overcome the "restrictive" exhaust port on the 331 head.
So if this is the source of my problem then would replacing the cam again correct my problem, or would a performance head from titan that has chevy swirl valves installed and greater flow on the intake and exhaust correct my performance.
Or is there some other issue that i am not seeing. I was hoping that someone may have some insight on my issue and possibly some experience with camming with the 331 head.
thank you