Head differences 95-97TM vs 98TM

[91exploreron37]

Alright heres the situation. My moms 97 Explorer has a stuck or not properly seating valve on the passenger side head so I found it cheaper to just buy a remanufactured head to replace it.

Well I ordered one from Odessa Cylinder Head on Ebay and stated I need a 97TM head with a "U" cast letter, but they sent me a 98TM head with an A cast letter and after I emailed them stating the problem they sent another head but this one is the 90TM head with the "T" cast letter. I emailed them again about the problem and am awaiting a response.

In the meantime I was wondering if the 98TM head with the "A" cast letter will work on the 97 explorer as I'm fed up with this and need to get this replaced ASAP.
This article says they are not interchangeable and I just wanted to get a second opinion:
http://www.therangerstation.com/tech_library/40rebuild.htm

Thanks

 

[91exploreron37]

Anyone?

 

[Turdle]

I used the search feature, typed in 95tm and found this

http://www.explorerforum.com/forums/showthread.php?t=246789&highlight=95tm

I also found other threads about 4.0 ohv heads.

 

[nitro71]

I found this article, don't know if it will help or not but it has a lot of information.

http://www.enginebuildermag.com/Article/2356/rebuilding_the_ford_40l_pushrod_v6.aspx

 

[91exploreron37]

I found this article, don't know if it will help or not but it has a lot of information.

http://www.enginebuildermag.com/Article/2356/rebuilding_the_ford_40l_pushrod_v6.aspx

Yea thats the same article TRS has on there website that I posted. I found my info in the link Turdle provided.

 

[Abbondanza]

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).

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.

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