Morley says...
HMM, WE ALL talk about interchangeability in cars, don’t we, but here’s proof that it doesn’t always work out like it does in the movies. And that’s despite the engine you’re trying to fit being an old–school Ford Windsor which, you’d reckon, would fall into a Mustang bay with room to spare. Also, Harry, this here can of worms looks to be caused by more than one factor. Not only is it a later model engine with later model ancillaries from a car with a different sized and shaped engine bay, you’ve also gone and converted it to rack and pinion AND changed it from left to righthand-drive. It’s a wonder the bonnet even shuts. (It does shut, right?)
However, you’re not the first bloke to come up against this sort of thing, and I’ve heard of a variety of solutions including starter motors with an offset for better clearance and a type of exhaust manifold called a block-hugger which, as the name suggests, keeps the header pipes in tight against the block for maintaining clearance. Sometimes a particular engine swap is so popular, header makers will engineer an off-the-shelf set to successfully mate two previous strangers (sounds like a crap reality TV show, yes?) But I also recall fitting the headers to my hillclimb project car recently, and noticing that one primary pipe ran reasonably close to the starter-motor and that the people who had made the headers, Pacemaker, had clearly thought this through and routed the primary in such a way that it still flowed the maximum amount but gave me just enough clearance to get the starter-motor in and out if I needed to. So I figured the brains trust at Pacemaker might have a solution for you.
I called Pacemaker’s tech guru, Mike, to find out what gives. According to Mike, who has an absolutely
“IT’S A WONDER THE BONNET EVEN SHUTS. (IT DOES SHUT, RIGHT?)”
encyclopaedic knowledge of what widget fits with what thingamy and when the metric jigger was introduced, your problem is multi-layered. For a start, just because you’ve used all Ford parts, doesn’t mean you’re still dealing with a car Ford would recognise. “You can take a running board from a Model T and a tailgate from an XP Ute and put them on a car. But you don’t have a Ford anymore,” is how Mike puts it. “Also, the Mustang is its own animal. People think they’re just American Falcons, but they’re not. In all the hundreds of applications we do, the Mustang is the only one where the headers don’t point straight at the back of the car; they’re actually offset a little.”
Mike reckons your biggest problem is that the five-litre V8 you’ve used has the starter motor on the passenger’s side. Clevelands and earlier Windsors had the starter on the driver’s side, but at some point before 1992, it was switched. And that’s your big problem because as far as Mike knows, nobody (Pacemaker included) makes a specific left-hand header for a late Windsor into a 1970 Mustang. By definition, that means your choices come down to two: You can try to cut and shut the headers you have to offset the collector or make more space some other way or, you can have a set of custom headers made specifically for the job. Actually, there’s a third solution: You could re-fit the cast-iron factory exhaust manifolds and sacrifice a few horsepower for an easier, simpler life. Either way, it’s not as simple as I’m sure it all sounded in the pub when the plan for an injected V8 into a Mustang was hatched. But don’t give up. And send us a photo when it’s done.
Meantime, anybody else out there carried out this same conversion? What was your solution to header clearance? What’s the magic part number, if one exists?