it has a whole bunch of internal upgrades (I can't remember them all nor can I remember the website I read it at, maybe some Jeep forum site) besides the cams. It also has a higher compression ratio than a standard 4.7. Again, it will run on 87, but you won't get the full performance out of the motor because of the retarded timing. When an computer retards the timing in order to prevent pinging (spark knock) power goes down the toilet.

I hope that helped some. If you can find the Jeep forum site that has all the info about internal upgrades it will help a lot more. You hear about a lot of people who will put in the HO cams into their standard 4.7. You will see a performance increase but your not getting the full benefit of everything Dodge did internally to the motor in order to handle the more radical cams.

 

sorry, I forgot it was 91. I don't see 91 sold anywhere in the mid-atlantic where I live so my only other choice above 89 is 93.

 

I run nothing but the 93 in my non-ho I can tell the difference. Anything less it dogs so it is worth the extra cost for me even tho it should run on 87. I wouldn't want that HO motor seem all you HO guys have engines that rattle.

 

not all. I am having that issue but I listened to some 4.7 HO's at a couple different dealerships about a month ago, no noise whatsoever.

 

you cant just run higher octance for better performance thats not how it works (non HO). u havta have certain upgrades that require it other wise the high octane makes things worse...if u got better performance just by using higher octanes everyone would be running around with 107.

 

http://www.wjjeeps.com/engine.htm

this is the site I was referring too