Are All 472 Exhaust Manifolds Interchangeable?

[mrleibel]

I have found a cracked exhaust manifold on my 1968 DeVille's 472.  Are other years of the 472 exhaust manifolds interchangeable with the 1968 version? 

Any insights would be appreciated!

Thanks,
Matt

[Scot Minesinger]

Almost sure that they are, except watch out as the Eldorado manifolds are different I believe.  The 472 and 500 have differences, the primary distinguishing factor is stroke, but manifolds may also be same.  The manifold bolts in the back towards firewall seem to be almost impossible to remove without breaking them.  Have heard some people grind off head of these bolts and then remove manifold making it much easier to soak with penetrating oil and then remove.

The heads/connecting rods/pistons/etc. are a little different from 71 on because of the lower compression ratio.  This may have a minor impact on exhaust manifolds.  1968 thru 70 should be similar or identical for rear drive Cadillacs.  Sorry, understand you probably knew all this.  Check with Jeff at Willington CAD or maybe Cadillac Tim.

Good luck,

Scot

[TJ Hopland]

As far as bolting on all the 472-500-425-368 manifolds are the same.   

The 425 era manifolds were very similar to the 472-500 ones except they were squished in a few places to get clearance in the downsized cars they when into.   I never looked but I assume the 368 ones likely had smaller ports and were maybe more compact for clearance.

The right side manifold was the same for both the Eldo and the RWD cars.  The difference in the right manifolds was the EFE valve.  Some years and some models had the EFE (early fuel evaporator) 'flapper' or 'heat riser' valve.  The valve was its own section that fit between the manifold and the down pipe.  The manifold had a different mating surface on it for the valve so they did not easily interchange with non EFE's.   The left manifold was different between the Eldo and RWD cars.  The Eldo 'dumps' almost horizontally out the back.  The RWD one is more typical and similar looking to the right side.