88 Commanche Engine Upgrade

[stevelake]

Anybody Have Info On The Possibility Of Upgrading 88 4.0 To A H.o. 4.0 Using The Same Block And Head That I Just Had Rebuilt?

[neon_rt]

The head is most of what makes the HO a HO.
The head design is different. I think you can directly bolt on a HO head on a non HO engine and get a big HP increase. Along with the HO engines came inproved fuel injection also. So just upgrading the head would not give you the full benefit. I've seen the bench flow test on the HO and non HO heads. A fully ported and polished Non-HO head has about the same airflow as a stock HO head. If you are going to do a rebuild, get a newer HO head from the junkyard to rebuild.