I6 to V8 conversion Ok, since we get asked this question about 9 times a day, I talked to the mod and got permission to start a sticky thread for this. What will I need to convert my 1964 1/2 to 1970 Mustang to a V8 ? Power Plant: You are going to need a complete engine. This means: All of the accessory brackets Front sump oil pan Flywheel or flexplate for the correct transmission Motor mounts Motor mount frame brackets for the type of V8 you are installing (big block or small block) Cooling system: You will need a new radiator, that I6 on is not going to cool your new V8 engine. Upgrade to a 4 core copper or a 2 core aluminum (aluminum cores are 2x the size of copper cores) New radiator hoses I recommend to run a seperate trans cooler if you have an auto transmission (as I live in a hot climate) Transmission: You don't technically NEED to change from your I6 trans, you could just change the bell housing on the transmission BUT believe me when I say that the your I6 trans will not survive long behind your new V8. The 250 and 300 straight sixes have the same mounting pattern as the small block V8 so if you have one of these motors in, you can bolt your existing trans right to the V8 (Info provided by Hack, also see tjnavyblue's comments a few posts down). I still highly recomend geting a V8 trans to use ! If you have an auto and want to upgrade to another auto there are a lot of options. Ask around and ask us and we can talk about what kind you want/need. Same goes for a car that will end up with a manual trans. Rear End/Driveshaft: You need to change your entire rear axle assembly. People have got away with not changing this out in the past but just like an I6 transmission, an I6 rear end is definately going to brake. It was not built to handle the torque of a V8 motor. You can easily upgrade to an 8" or a 9" rear end (9 inch will cost more and may not be worth it for you). An 8.8" rear in is also possible but it is a lot of trouble and for the same or little more money you can have a 9". As for the drive shaft, you are going to want a brand new one. Most of the early drive shafts were 2 piece units and they are not reliable and should be replaced ASAP. Stuff like that always brakes at the most inconvienent times. Front suspension: You are going to need to change the front suspension for a couple reasons. Your rear end now has a 5 lug wheel pattern and your front has 4, matching is a good thing. Also, the old 4 lug stuff isn't strong enough to support that new V8. You will need to change your: Front spindles Coil springs Shocks Upper control arm (not sure) Lower control arm (not sure) Strut rods (not sure) Rear suspension: Leaf springs Shocks Brakes: Hopefully the V8 spindles you get will get will have brakes with them. If not you are going to need to put some brakes on them. You can get drum brakes for the front but DON'T. There are a myriad of brake options for the front of these classic Mustangs so put on something that will stop the car well. This isn't the place to discuss brake upgrades. Maybe we will make another sticky for that later ! Just make sure you put on adaquite stoping power for you new motor ! As for the rear brakes, a lot of people feel that drums are fine. I'll be puting discs on my rear soon, I don't like the way drum brakes react and they are a pain in the butt to service. Steering linkage: More stuff to change ? Thats right. Inner tie rod Outer tie rod Drag link Idler arm Exhaust (added at 65fastbackresto suggestion): Your I6 exhaust system is not going to work with your V8. You are basically going to need an entirely new exhaust setup. It is more expensive, but PLEASE try your best to get a mandril bent exhaust instead of a crush bent exhaust. They look better and perform much better. Misc. On a 64-66, the gas pedal will need to be changed (added at 65fastbackresto suggestion). I'm not sure about other years. Now, I don't claim that this list is 100% complete or 100% accurate. Little things vary by year and I might have forgot stuff. As people post more or PM me information I'll edit this post to make it more complete and accurate. Something we didn't cover in here ? Post it in the forum !