Topic: Exhaust Heat Riser Tube 289 Engines

[krelboyne]

I believe that this tube was used 1965-67 on 289 engines (non-HiPo). While sorting out inventory, I discovered 4 variations. My thinking is the early (1965-66) version has the almost full shroud on the exhaust manifold, 1967 is more cut away. I have several examples of a 'flat spot' on the riser tube, was it for cars with emissions? The version of the MPC gives a part number of C5ZZ-9A603-B, but notes for 'open emissions'. The 1967 Engine Assembly Manual notes the casting number as C6ZF-9A607-D or -E. Please note differences in pictures.

[67gta289]

Here's mine from a 67 C code, San Jose assembled car, DEC 66 Windsor built level 15 engine E-226-B with Thermactor.

[krelboyne]

Thanks John.

Should have mentioned that all of my Cougar examples for 1967 are Dearborn built.

[J_Speegle]

There is the possibility IMHO that there were a couple of vedors that supplied these. We found two different versions of the Cobra Jet heat shields a few years back

[67gtasanjose]

I have two known from off of 67's with thermactor systems  and both have the flat depressions with the cut-away.

I also fit them to my engine and the flat depression does NOT align with any of the emission related items (which are on the front of the head on the passengers side) and has no visable reasoning for being there. It may allow just a little more room for the plug wires but really, there is already enough room for those.

I might side with Jeff on different suppliers.

I might also side with Scott's suggestion that the 65-66 version may be the full, non cut away type but we would need more "known original" examples to determine if that speculation has much merit. It looks like all will "fit & function" the same.

[krelboyne]

I was hoping someone with a 1966 289 with thermactor could chime and and verify if the smog tubes needed the additional clearance. Could be just a carry over into 1967, even though they wouldn't be needed for clearance.

[Murf]

Scott, just checked our 66 with thermactor and the "smashed" part of the heat tube does in fact give a little extra room for the air manifold that goes in the exhaust manifold.  I am not sure if one of the round tubes would work with the log type air manifolds but it would certainly be close without the flat spot.  Just for information our car has a scheduled build date of October 30 (1965), built in SJ, 289 two barrel with C4,  PS and AC.  Hope this helps in some way.

[67gtasanjose]

I was hoping someone with a 1966 289 with thermactor could chime and and verify if the smog tubes needed the additional clearance. Could be just a carry over into 1967, even though they wouldn't be needed for clearance.

There you go! That makes VERY good sense (forgot about those "ugly" tubes!)

Scott, just checked our 66 with thermactor and the "smashed" part of the heat tube does in fact give a little extra room for the air manifold that goes in the exhaust manifold.  I am not sure if one of the round tubes would work with the log type air manifolds but it would certainly be close without the flat spot.  Just for information our car has a scheduled build date of October 30 (1965), built in SJ, 289 two barrel with C4,  PS and AC.  Hope this helps in some way.

Makes perfect sense now. Some early 67's with Thermactors (to my understanding) depending on the change level of the engine, may have had the tubes into each exhaust port. There doesn't seem to be a change-over date in print that I am aware of (maybe Mannel's book? I don't have one), it likely differs between engine codes ("C", "A" or "K")  as to when they ran out of the older version with the seperate tubes and switched on the production line into the "single" injection port more often seen on the '67' 289's.

Good discussion! More layers of "discovery" found out (at least for me)

MURF: Do you have any pictures of you convertible with the removable hard top? I am curious how that looks. I actually considered such a special build with using another convertible body and cutting the "vinyl roof" styling from off of my coupe (back in the 80's) ...my plans then were to have a convertible OR hardtop and to have the full-sized hardtop seat and rear deck. I never did get that "dream" under way...but the "dream" included going 4x4 using the front suspension out of an AMC Eagle!    My undeveloped idea was a bit extreme...but I thought Mustang Monthly would have enjoyed it!

[67gta289]

According to Mannel's book, appendix A, page A-4 the heads cast in Cleveland were designed to use and external air log and tubes for each cylinder.  The heads cast in Windsor were had internally machined passageways and cross drilling.  There are no dates specified.  There is an indirect reference that this applies to 1966 and 1967 but that is a loose reference. 

[Murf]

Richard, sent you a PM