Reviving Dead Cobra

[C5GTO]

Now on to my current Cobra revival dilemma, the EFI/ECU system, should I stay with existing or upgrade to newer technology? I was anticipating getting the new long block motor, dropping it in the Cobra, topping it off with the old EFI unit and having it on the road already. I’ve had the new engine in my possession for about a week now, I’ve been busy “preparing” it for install and no rumble from the side pipes yet.



When you have a collection of aftermarket parts that make up your engine (the engine block is the only component sourced from a Ford factory), it’s most often more complicated in real life than in theory. Ford changed several things on these small block Windsor motors over the years that is most often the root cause behind complications. Things like drive belt pulley spacing, water pump hose inlet location, timing indicator/pointer location and an EFI intake that extends over the valve covers. So as I was working through preparations/adjustments, I decided to trial fit the intake manifold. I had made the assumption that if the intake fit over the existing valve covers and these same valve covers were used on the new engine, then the intake should also fit with no clearance issues on the new engine. Here’s a picture of the old EFI intake that has been on the car since original build.



So I went to great lengths to make sure the old valve covers would fit over the new engine valve train and thus I should avoid any complications there. That assumption proved false and my biggest complication so far. It turns out the new aluminum head castings are taller than the Ford X302 aluminum head castings that were in the old engine raising the valve covers upward by about ¼ inch. It’s no wonder why these heads flow better, they have more room for the passages and ports.

This wouldn’t normally be an issue but it is if you have a big, wide intake with minimal/no clearance between the intake plenum and valve cover top. I had to squeeze out all extra space way back when to fit the engine under the hood (even lowered the engine mounts by 1” as well). So even after grinding away about 1/8” of material on bottom of intake plenum, there’s still a gap in the upper and lower intake flange of about 1/16”. Any more grinding and there will be a hole into the intake, not good.

In trying to identify all possible resolutions, it occurred to me that an upgrade to a Weber style 8 stack EFI would work. In pricing it out, yikes, that’s an expensive option but boy, wouldn’t it like right at home in a Cobra.



I could also go down the path of buying a different long runner intake that has a shorter plenum, would fit over the top of the higher valve cover and still fit under the hood. A much cheaper alternative but just doesn’t have the same eye candy appeal of Weber throttle bodies.



If the 25 year old EEC IV system is left in place, it’s really a ticking time bomb and potentially the cause of the prior piston failure. Upgrading the ECU is a possibility but is doing that just a slippery slope to a new throttle body, distributor/ignition system, etc. etc. All this to just end up with an EFI intake that doesn’t really look right in a Cobra anyway. Those Weber ITBs sure have the right look but at 4X the cost, yikes!

Are there other viable alternatives I’m missing? I don’t really want to go a non-EFI option like carburetors. I’m told that the Borla ITBs are really the only non-junk ITB option out there.

I’d be interested in hearing your thoughts, options, etc.