Acceleration help



Hey I just recently purchased a 1966 coupe with 200. My problem is it is a little sluggish with acceleration, I attribute some of the problem to the tire size, they are slightly too big. I was wondering if anyone out there could give me a few pointers on boosting the acceleration without taking off or getting new tires. The engine is bare, all of it is standard, no performance to it. So any suggestions you can offer are good. The engine has 6000 miles on a rebuild, before that it had around 264,000 miles. Thanks for your help.
8) Depending on how mechanically inclined you are and how much money you want to spend the single biggest improvement to acceleration is adding rear gears. Alot of the inline six Mustangs have 2.73:1 gears.

Just switching to 3.08 or 3.27 gears makes a tremendous difference. I have a 3.45:1 geared rear for mine, several of the guys are running 3.27:1 geared rears.
Check your timing.

Also check to make sure you are getting full opening on your carb. I checked one out for a friend who was complaining about lack of power after a rebuild only to find that he had misadjusted the linkage and was only getting half throttle with the pedal to the floor.
How much would better gears cost? And exactly how much time do they demand to be installed?
Unless you are very good at working on cars you are best off having it done by someone who works on rear ends. To change out gears requires some press type tools. You are looking at around $650 labor plus all the correct parts to do it. I wouldn't go with nothing above a 3.73 if you are runing more stock and want a lot of take off power. Once you start lowering gears you won't find that much difference in the gas mileage equaling the power difference. You will notice a lot of difference in your rpm's at cruising range but I wouldn't worry about it. 2800-3300 range is no problem.
Do you guys have any suggestion on where to find these parts , and maybe a brand? I'm a little in the dark with this stuff, but want to make a future note so I can include it in my future budget and plans.
The cheapest way to gear is still tires. A set of 185/70-14s will run you $250 for really good touring radials (check, and you won't even get your hands dirty. :LOL:
I too am looking at changing over to a 3.27:1 rear end. Where can I find a set. Also, does anybody know what size rear end a 68 mustang has, 8", 9", I can't remember :oops: ?

...........Thanks, Alex
I haven't had the chance yet.... not really sure how to... maybe you could explain how to adjust the throttle?
LOL. I am good with some stuff...but things that elude me are timing, adjusting the carb and tech stuff like gearing and torque...

have mercy on us amatuer gear heads!!

If you look at the carb linkage you'll see that it's threaded. Have someone hold the pedal to the floor while you look at the carb. If the throttle is not opening completely, snap the end of the linkage off the throttle ball and lengthen the linkage.

Very often a new carpet or floormat amy prevent you from opening the throttle all the way, so check that too.

Cover the basics before diving into new gears, multiple carbs, cams, and stuff.....
Bottom line is still overall gearing. With those tall tires you need a lower gear, or you'll feel like you're starting in second gear. :shock:
Which brings up another point. If you have the gear selector in the wrong position on a "green dot" C4, you do start in second gear!
Ok, I will check all that as soon as it stops raining...grrr... hopefully sometime midweek. I will give you an update as soon as it stops raining.....
Hey, don't complain about rain. :cry:
We are in a drought, but it snowed today. :roll:
Make sure your shifter is pulled back to the second, not first D. ;)