1965 Mustangs are 55 years old. In their wildest dreams, I doubt that FoMoCo thought that they would see early Mustangs still on the road in 2020. I think that there are no parts or components that you cannot purchase for a 1965-1970 Mustang these days. The problem is that many of the parts are no longer offered at your local Ford dealers. The vast majority of parts are offered only from the aftermarket industry, with many of those parts being built off-shore. Motor mounts are at the top of the list. There are some nice looking motor mounts out there, particularly the ones that use a non-rubber insulator such as Pro-Thane or Energy Suspension. There are also the "replacement style" motor mounts, the kind that you can get at the local Auto Parts stores (like NAPA, Auto Zone, O'Reily's, etc.). These look like the original style mounts, but many of them are not even close. (I purchased a set of 1966 engine mounts from a Ford dealer last year, and it said "made in South Korea on it") They will bolt on to the chassis, and also bolt on to the engine, but they frequently lower the engine in the engine bay. With the naked eye, it's not easy to distinguish any difference. This holds true with some of the Energy Suspension mounts, too. I have seen some that lower the engine as much as 3/4", and again, it's tough to tell if you open the hood and look at the engine. For 98% of the things or components that you may bolt on to your engine, it really makes no difference if it sits a little lower in the chassis, and in fact, it can give you some additional room for a larger air cleaner without hitting the hood. This is particularly true if you have swapped in a 351W block to replace your old 289 or 302 engine.
But for Long Tube Headers, 1 3/4" primaries and above, beware. The headers bolt to the engine, and if the engine sits a little lower (sometimes by as little as 1/2"), the headers may come into contact with the chassis sub-frames, the steering system, or the suspension system. As the engine drops down, so do the headers, while the rest of the vehicle does not change. Every header manufacturing company that I know of builds their headers to fit on an engine in the stock, OEM location. "Stock" means that the engine is not sitting lower, or higher, or further back in the chassis. It also means that the engine is sitting in the stock location side to side. Many folks do not realize that the engine is NOT located at the centerline of the car, it's usually a little closer to the passenger side than the drivers side. When you are sitting in your Mustang, look at your feet. The driver's side floorboard needs room for three pedals. There are no pedals on the passenger side. Shifting the engine toward the passenger side a little also gives more room for the shift linkage on the transmissions in the trans tunnel. Several of these Mustang II suspension / steering rack kits for the early cars center-up the engine.
Anyone that has ever had to install (or tried to install) long tube headers on an early Mustang knows that there is very little extra room in there, between the engine and the chassis. If the engine is not EXACTLY where it needs to be (which is the stock OEM location), interference between the headers and the chassis is entirely possible. And again, it's very difficult to tell if the engine IS in the stock location. Sometimes your first clue is that the long tube headers you are trying to install hit something on the chassis or steering system. It's usually not a problem with the headers, it's either that they engine is not in the OEM location, or there are aftermarket suspension, chassis or steering components in the way, AND the engine is not in the OEM location. RCI Headers makes no bones about these issues, we go out of our way to warn potential customers in advance on our website. If the engine is sitting a little too low, we can usually fix that situation over the phone, but the reality is that the early Mustangs are between 50 and 55 years old. I suspect that the enthusiasts that have them now were not the original owners. I suspect that the majority of you that own the car now have no idea how many owned it before you. You may THINK that the car is totally original, but only a few really are. In short, and I kind of hate to say this, if you are unsure about your early Mustang, if you are not handy with tools and don't know how to modify things as needed, or have someone you can go to if you need to, this is probably the time to consider Shorty Headers (just saying the word makes me cringe)...
But for Long Tube Headers, 1 3/4" primaries and above, beware. The headers bolt to the engine, and if the engine sits a little lower (sometimes by as little as 1/2"), the headers may come into contact with the chassis sub-frames, the steering system, or the suspension system. As the engine drops down, so do the headers, while the rest of the vehicle does not change. Every header manufacturing company that I know of builds their headers to fit on an engine in the stock, OEM location. "Stock" means that the engine is not sitting lower, or higher, or further back in the chassis. It also means that the engine is sitting in the stock location side to side. Many folks do not realize that the engine is NOT located at the centerline of the car, it's usually a little closer to the passenger side than the drivers side. When you are sitting in your Mustang, look at your feet. The driver's side floorboard needs room for three pedals. There are no pedals on the passenger side. Shifting the engine toward the passenger side a little also gives more room for the shift linkage on the transmissions in the trans tunnel. Several of these Mustang II suspension / steering rack kits for the early cars center-up the engine.
Anyone that has ever had to install (or tried to install) long tube headers on an early Mustang knows that there is very little extra room in there, between the engine and the chassis. If the engine is not EXACTLY where it needs to be (which is the stock OEM location), interference between the headers and the chassis is entirely possible. And again, it's very difficult to tell if the engine IS in the stock location. Sometimes your first clue is that the long tube headers you are trying to install hit something on the chassis or steering system. It's usually not a problem with the headers, it's either that they engine is not in the OEM location, or there are aftermarket suspension, chassis or steering components in the way, AND the engine is not in the OEM location. RCI Headers makes no bones about these issues, we go out of our way to warn potential customers in advance on our website. If the engine is sitting a little too low, we can usually fix that situation over the phone, but the reality is that the early Mustangs are between 50 and 55 years old. I suspect that the enthusiasts that have them now were not the original owners. I suspect that the majority of you that own the car now have no idea how many owned it before you. You may THINK that the car is totally original, but only a few really are. In short, and I kind of hate to say this, if you are unsure about your early Mustang, if you are not handy with tools and don't know how to modify things as needed, or have someone you can go to if you need to, this is probably the time to consider Shorty Headers (just saying the word makes me cringe)...