Abbondanza
Well-Known Member
- Joined
- June 13, 2011
- Messages
- 181
- Reaction score
- 0
- City, State
- Long Island, NY
- Year, Model & Trim Level
- 1996 XLT 4.0 OHV 170k
Okay I've read every thread out here about the exhaust port differences between the 95tm stock head (with the 'U' stamp) and the new heads out there (98tm) with the SMALLER exhaust ports.
I ordered new heads from Clearwater and I told them I have the larger ports style head (95tm), and of course they were delivered today and the new ones have the smaller exhaust ports (98tm). Called them up and they indicate that the important part of the heads matching is the combustion chamber (which the two styles do have in common), and that the exhaust port size is negligible.
I understand that the smaller ports were designed to increase exhaust gas speed and heat up the cat quicker for cold-start emissions improvement.
My question, which I haven't read fully/definitively answered in the other threads is:
If I put these heads on my 96 4.0 Engine, will there be problems or performance issues? I am just looking for a reliable, well running truck again, but I do not want to install these if there will be noticable side effects to the engine peformance, such as pinging, HP loss, etc.
Other threads say 'probably not a good idea' to use the 98tm heads, but my thought is did Ford change the OHV engine in other ways after these heads were released to production so that the 96 4.0 engine would not perform correctly with these heads?
Anyone with some concrete opinions on this? Would like to complete his job this weekend unless there is a strong reason to return these heads.
Thanks, Jon
I ordered new heads from Clearwater and I told them I have the larger ports style head (95tm), and of course they were delivered today and the new ones have the smaller exhaust ports (98tm). Called them up and they indicate that the important part of the heads matching is the combustion chamber (which the two styles do have in common), and that the exhaust port size is negligible.
I understand that the smaller ports were designed to increase exhaust gas speed and heat up the cat quicker for cold-start emissions improvement.
My question, which I haven't read fully/definitively answered in the other threads is:
If I put these heads on my 96 4.0 Engine, will there be problems or performance issues? I am just looking for a reliable, well running truck again, but I do not want to install these if there will be noticable side effects to the engine peformance, such as pinging, HP loss, etc.
Other threads say 'probably not a good idea' to use the 98tm heads, but my thought is did Ford change the OHV engine in other ways after these heads were released to production so that the 96 4.0 engine would not perform correctly with these heads?
Anyone with some concrete opinions on this? Would like to complete his job this weekend unless there is a strong reason to return these heads.
Thanks, Jon
