4.0 head change dyno results
tinman
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- Idaho Falls
- Vehicle(s)
- 81 CJ7, I6, T5, D300, 4.2 block with a 4.0 head, Cherokee MPFI
Just got back from the dyno, and while not exactly a straight swap, it's pretty close.
First pull was back in April with a stock CA AMC 258 i6 / 4.2l engine, but with all smog stuff gone. It did have the 2100 carb and HEI for the test, but everything else was stock.
166.1 ft-lb@ about 2250 RPM's and 88.1 HP@ about 3300 RPM's.
Today's test had an '84 block, bored .030 over, '95 7120 head(rebuilt, but stock), and a comp 252 duration cam. Same carb and HEI, but I did replace the muffler with a new magnaflow one.
224.3 ft-lb@ 2500 RPM's and 140.3 HP@ 3500 RPM's.
So, a gain of 58 torque and almost 52 HP with mostly just the head. I'm not sure how much the cam, the boring, and the muffler added, but I was pretty happy with the results!
Now I need to get off my rear and start a build thread I guess
. I still plan on doing some sort of FI sometime, just not sure when, or what kind.
First pull was back in April with a stock CA AMC 258 i6 / 4.2l engine, but with all smog stuff gone. It did have the 2100 carb and HEI for the test, but everything else was stock.
166.1 ft-lb@ about 2250 RPM's and 88.1 HP@ about 3300 RPM's.
Today's test had an '84 block, bored .030 over, '95 7120 head(rebuilt, but stock), and a comp 252 duration cam. Same carb and HEI, but I did replace the muffler with a new magnaflow one.
224.3 ft-lb@ 2500 RPM's and 140.3 HP@ 3500 RPM's.
So, a gain of 58 torque and almost 52 HP with mostly just the head. I'm not sure how much the cam, the boring, and the muffler added, but I was pretty happy with the results!
Now I need to get off my rear and start a build thread I guess
