Scratch That, 4.0 Mild Build and Upgrades

[CDW6212R]

This is good info i didn’t know. Is it only the Limited’s?

The higher option models should all have the high amp alt.

I learned that when I bought my 99 SOHC from a JY, it had a few parts missing, and they found another alternator for it. The one they gave me was a 3G and wouldn't work on the SOHC, that and the 302 use a 4G unit. So it was a spare alternator until a year later my 91 ran the battery down. I didn't fix the old alt, I just bolted on that spare.

The under drive pulleys for the 4.0 aren't as extreme as old Fox Mustangs(I have those pulleys on my 91 HO 302(that required a better alternator)). You should be fine with the 4.0 kit, just watch the coolant temps idling in high heat, and the charging voltage with lots of things turned on.

An electric fan should be run by a PWM controller, they apply far less current when turning on the fan, instead of the high current shock of a simple relay.

 

[19945speed4x4]

The higher option models should all have the high amp alt.

I learned that when I bought my 99 SOHC from a JY, it had a few parts missing, and they found another alternator for it. The one they gave me was a 3G and wouldn't work on the SOHC, that and the 302 use a 4G unit. So it was a spare alternator until a year later my 91 ran the battery down. I didn't fix the old alt, I just bolted on that spare.

The under drive pulleys for the 4.0 aren't as extreme as old Fox Mustangs(I have those pulleys on my 91 HO 302(that required a better alternator)). You should be fine with the 4.0 kit, just watch the coolant temps idling in high heat, and the charging voltage with lots of things turned on.

An electric fan should be run by a PWM controller, they apply far less current when turning on the fan, instead of the high current shock of a simple relay.

Agreed on the pwm controller. I need to add all the prices up. See where I’m at.

 

[19945speed4x4]

You nailed it on the head. Cost vs performance gained is really what matters. But you brought up hollow push rods lifters with oiling holes and the roller rockers. That should be a must have for every 4.0 ohv. I will atleast be doing pushrods n lifters when I go to replace mine.

When people say cost, it should be said that its money and time. I can swap out a 4.0 in a weekend easy which is why I'm going this route. Seems to me the hollow pushrods and lifters aren't too much more expensive than stock.

 

[Nadams01]

When people say cost, it should be said that its money and time. I can swap out a 4.0 in a weekend easy which is why I'm going this route. Seems to me the hollow pushrods and lifters aren't too much more expensive than stock.

True it's just a common misconception that people get about 4.0 they expect huge power gains with a cam and all the other stuff when it won't it will definitely beef it up but not ls levels of power increase. But yes the hardest part of lifters pushrods is gonna be the valve springs

 

[Nadams01]

The electric fan i found pulls 18 amps at full load. 3300 cfm. Planned to get a 130 amp alt and let the local shop work their manic on it. Not worried about cooling it. A/c has me worried. More rpm=colder ac?

Gotcha that is way lower than expected. What fan setup? Also no on the rpm vs ac the clutch cycles on and off based on the pressure sensor on the low side to maintain pressure above 24 psi and below 38 or 40 so regardless of engine rpm it is self managed.

 

[19945speed4x4]

Gotcha that is way lower than expected. What fan setup? Also no on the rpm vs ac the clutch cycles on and off based on the pressure sensor on the low side to maintain pressure above 24 psi and below 38 or 40 so regardless of engine rpm it is self managed.

It’s the black magic 188? I believe. Will double check.