Hipo exhaust manifold lock tabs

It depends on the supplier, most were natural steel with some overspray

I'm just basing my observation on a few low mileage cars. Keep in mind that even if the lock tabs were natural when installed, they would have gotten paint over spray on them when the engine was painted. So, this would most likely have prevented any flash rust. I would accept natural or black dipped on a concours car, but for concours, they ought to have some engine block over spray.

The examples I have seen that were black include one built close in production to your car at Dearborn. If it was my car, I would probably dip them in black paint, install them and then apply black over spray, which would cover the bolts, washers and also make it's way onto the manifolds.

I have looked very carefully at some old locking tabs I have for standard engines. It is my conclusion that the locking tabs got painted when the engine was painted. This is based on looking at dozens of locking tabs and finding no paint under the bolt head area or on the inside surface of the bolt holes. The bolts fit fairly loosely through the holes, so if they had been painted there, it would not have been scraped off. It was also a very well protected area where I would expect the paint to survive, particularly on those tabs that still had significant paint still remaining. I would have also expected to see some remnants of paint under where the bolt head was. I could find not the least trace of paint on any of the tabs. There was also no evidence of any dipping. There were no runs or streaks indicating a draining pattern. In short, I could find no concrete evidence the tab was definitely painted apart from the engine.

But, there is good evidence to suggest the locking tabs were painted with the engine. I have a few pictures of a low-mileage 1966 Mustang 289-2V that I took many years ago. I took some pictures around the exhaust manifolds. The overspray around the exhaust manifold attachment area is clearly evident. I believe that the overspray was far more significant than it might first appear. What is left on the manifolds is what has not burned away after thousands of miles. But much more was likely there when the engines were first painted. Note in the pictures how heavily the one exhaust bolt is painted blue. Ford did not paint hardware. Hardware got painted with other items (like the lower head bolts getting painted). You can even see on the close-up how the tab shielded the lower bolt from paint and evidence of some rust under the tab on the bolt head.

Evidence suggests that the engine was well painted around the exhaust manifolds and during that time the locking tabs and bolt heads were well covered -- probably not in all cases, but most. As a result the tabs were painted black on 1962-65 engines and blue on 1966 and later engines.

In looking at the tabs, they appear to be a natural steel. There is no indication there is any coating on them. They appear to have been stamped cut items. There are shear markings on all edges. Probably stamped into the desired S-bend after cutting.

Anyway, that is what the evidence suggests -- no special coating, just plain steel; not dipped, but installed bare; then painted with the engine.

[Blocked Image: http://www.fordsmallblock.com/Pictures/exhaust-paint-1.jpg]

[Blocked Image: http://www.fordsmallblock.com/Pictures/exhaust-paint-2.jpg]