QSACFoxbody

Hey guys,
I've been driving around my 1984 Mustang for a few weeks now and it just seems a bit sluggish to me. It became more evident when I took it to Irwindale speedway to see how it would do stock before adding any mods. The best it ran the 1/8th mile was 10.3 @ 63 MPH and this is on drag radials/skinnies with race star industries wheels and a semi stripped interior. My foxbody has a stock motor besides a 650 4 barrel carb with a Edelbrock performer intake and underdrive pulleys, World class T5 from a 1999, 8.8 rear end with 2.73 gears. Spark plugs were changed since I thought this was the problem and the base timing is already set at about 13-14 degrees. Had a lot of backfire at the carb when at WOT before i changed the spark plugs but now it occasionally happens when trying to accelerate. When trying to accelerate it just doesn't feel like the car is accelerating at all so I'm trying to fix any mechanical issues before actually adding mods to it. Could it also be related to the loud jolt I hear from the rear end when I go into a different gear? Any help is appreciated

dawson1112

One that that immediately stands out to me are those 2.73 gears. Those are Cadillac gears for cruising down the highway. Jump up to a set of 3.73 gears and it will be a new world. Now you should know already that thunk in the rear when you shift gears is not a good thing, you need to get back there and check the U-joints, and also pinion play. Oh and the 302 only made around 175 hp in 84. You could always pull that old 302 and drop a 5.0 HO in it and that would get you up to about the 220 hp. Sadly all the early 80s cars suffered from government regulations on fuel efficiency so they really were not that quick. If you want to keep the original block in the car you can put a cam and some decent heads on it and get it to put out some decent power, but if I was you Id pull it and get a good 5.0 roller block to build instead of putting money in that 302.

QSACFoxbody

Yea I'm in the process of getting the 3.73s or 4.10s i can't decide since I sometimes drive this car on the street for pleasure or drive it to my mechanic shop which is a 30 minute drive. Could the thunk in the rear end be caused by a driveshaft that is too long? I had a thought of this since the transmission is from a 1999 (T5) and the rear end was swapped to a 8.8. Well I'm going to be adding nitrous to car maybe a 150-200 shot since we want the engine to blow to be able to swap in a lightning engine. I just don't want to put a lot of money into this engine since it won't be what I want to run in the end game just a short term engine that I want to have fun with hence the nitrous being added soon. Also I know the 150-200 shot is a crazy amount but we know what we're doing with it and don't care about the longevity of the motor.