Difference Between a 4.0L and a 4.0L HO

[worthin08]

What is the difference between a normal 4.0L and a High output 4.0L and i am building my 4.6L ca i take a high ouy put intake and bolt it onto mine and make it higher performance or what can i do thanks?

[stxj]

off the top of my brain:
high output engines are 1991 and newer. The good intake is found on 1999 and newer. The high output engines have better heads, something about the floor thickness is better for flow. there should be more to it , but thats my quick summery.

[amcinstaller]

thats pretty much it. 90 and down is renix, 91 to 95 was HO, 96+ is obdII. 7120 is the "best", but theres always arguements that the 0630 or 0331(i forget which one right now, but 0331 is glaring at me) head has better flow, but was more prone to crack unless it has TUPY cast into it.

[woodjeep]

sometime around 93 or 94 they removed the HO designator from the 4.0 l emblem on the back but everything enginewise remained the same

[4.whoa]

The '90 and older are renix- non HO. '91 started the HO the ports in the head are higher -better line-of-sight giving it better flow. You shouldn't use those intakes with a renix head as the ports do NOT line up. If you swap the head as well, you're fine, but you have to adapt the sensors. (Tps & iac)The 0331 "tupy" head has the best exhaust flow due to its raised floor, but you should use the matching manifolds as they are supposed to be slightly different as well.

[amcinstaller]

i knew the 0331 was lookin at me for a reason, thanks for the confirmation