When you decide to convert a six-cylinder Mustang to a V-8, what do you need to get the job done? First, you need the vehicle, engine and driveline, brakes, and suspension to be cohesive. This means you cannot and should not do it half-way and on the cheap. In other words, don't just drop a V-8 into a six-cylinder Mustang without changing the rear axle and all underpinnings.
You're also going to have to decide what you're going to want from your Mustang when the conversion is complete. Be committed to what you want the car to be and stick to that plan. When you don't, it gets expensive. What's more, do your homework ahead of time and know what will work well together and what will not.
Here's what you're going to need in a nutshell:
- A rebuildable 289/302/351ci V-8 or a new 5.0L/5.8L crate V-8
- Appropriate transmission and related parts
- Driveshaft
- 8-inch or 9-inch Ford rear axle housing/differential (8.8-inch late-model optional)
- New front and rear suspension parts
- Front disc brakes with power assist (make sure the power booster is compatible with your clutch linkage or hydraulic clutch master cylinder)
- Exhaust system, including headers or manifolds
- New cooling system with high capacity radiator, water pump, hoses, 180-degree thermostat
 A good, reliable six-to-eight...  A good, reliable six-to-eight conversion begins with a terrific engine. Even if you have a limited budget, build a healthy engine to begin with. It doesn't have to be modified; a stocker produces good low-end torque for the street. In tough times, aim more for reliability and less for brute performance. |  A reliable engine is the sum...  A reliable engine is the sum total of its parts and building technique. When Trans Am Racing built our Six To Eight 289 a couple of years ago, it utilized with the best parts possible for a budget daily driver... |  a 289 1M cast iron crankshaft,...  a 289 1M cast iron crankshaft, C3OE rods reconditioned with new ARP 5/16-inch bolts, hypereutectic flattop pistons with ductile iron rings, and a mild flat tappet hydraulic camshaft (roller cam is more expensive, yet more efficient). When you focus on the basics, the rest comes easy. |
 Pre-1982 small-block Fords...  Pre-1982 small-block Fords have two-piece rear main seals, which can leak no matter what. These blocks can be machined for a one-piece rear main seal, which is a great idea. If you're going to stick with a two-piece seal, stagger the seal gaps so they're not in line with main cap parting gaps. |  Fuel injection or carburetion?...  Fuel injection or carburetion? Much depends on how you intend to drive your Mustang. If you're building a daily driver, consider the ease and simplicity of electronic fuel injection - ideally a Ford factory set-up copped from a late-model 5.0L Mustang. If you choose carburetion, opt for the most reliable stuff out there. The most reliable four-barrel carburetor out there is the classic Autolite 4100 from Pony Carburetors on top of an Edelbrock Performer or Performer RPM manifold. Holley's trusty 1850 is also a good carburetor. Keep sizing around 500-600cfm. | |