How do I know if I have a 5.8 high out put in my 92 F-250 heavy duty? The former owner says that is what it is so I am intrested to know what the differance is between the HO and the standard 5.8. Thanks Jack

 

im curious as well as i have an 5.8 ho in my truck as well but still don't know what is different.

 

I believe the 5.8L HO's were the fuel injected engines which came out in '88 and stamped with the code "H", the earlier carb'ed 351's were just regular 351's. The "R" code 351's were found in the GEN 1 L's 93-95, and those shortblocks may have been in a few regular F series pickups, but I can't say for sure.
One of the differences between the regular 5.8's and the H.O.'s were the heads, cam, and the addition of EFI. From what I've read, the heads on the ealier models are just 302 heads with 1/2" head bolt holes. The mid 90's and later HO 5.8 blocks were drilled and tapped to accept a spider (and stamped with a "F4TE" type code that is near the starter) for a roller conversion, and in mid/late 96 some actually came with roller cams from the factory.

 

My carbed '85 Bronco had a 351HO. Don't know what the difference was though.

 

My 87 F-250 has a 351 HO with a carb. on it. Not sure the difference between the two but someone around here does.

 

Hmmm...I didn't know that the HO's went back that far, unless the earlier HO's were equiped with 4bbls???

 

My friend has a H.O. 5.8 on his '84 carb'ed and 4v also head design flow.

 

yes but we are wanting to know about 88+ 351 HO engines with fuel injections.

 

The only thing I can think of is there may be a difference between the 351's in the F150's and the 351's in the F250's and up. I think there are some emissions system differences, but I'm not sure what else. Horsepower and torque ratings should be the same as far as I know.

 

why would they be called high output then? and the 87 older ho engines had different hp and torque ratings. mines an f-150 but my grandad when he bought it new had the better engine put in at the factory.

 

modru2004 why don't you go find out and tell us what the difference is. Seems that the same upgrades they did to get a 5.0 to a 5.0 HO they did to the 5.8, except I am not sure on the cam. Can't you just look on the upper intake manifold and it says 5.8 H.O. !!! as far as I know all came like that. But I don't know because I run a straight six............ with a 351w L.O. waiting to go in from the garage.

 

The actual "H.O. 351" was phased out in '87. It was a stock block with a bigger cam, and a holley 4bb carb, they also put better heads on it. I have a '92 E150 with a 351 H.D., which is similar to the HO, the throttle body is ~56mm instead of 49 or 51mm (I forget the stock size) and the upper intake runners are a little longer.

 

So...all that being said...Does anyone know what the HP ratings are for the early 90's 351HO? Thanks!

 

why don't i go out and tell you the difference? because im not a frigin mechanic. i don't know that much about the engine thats why im here, you really think i would be able to tell you the difference when i don't know the exact specs of the reg 351? yes just because i have the dang engine im a super genius mechanic that knows everything.