I agree w/ Larry, running 26" tires vs 27/28 tires wud' nt be noticeable, for the most part. I run 26" tires, 2.79 gears, mild cam, long tube headers, 600 Holley and at 70mph running a hair below 3K rpms. I drive my car to distant events, local events and I wud'nt change to 3.55's w/o going to OD trans. I accept the fact of not having jack-rabbit acceleration, a price I accept for reasonable fuel mpg, less drv train noise and cooler running engine. Not driving much highway -- go for the taller gears.
You guys are seemingly underestimating what just 1 inch of diameter change has on speeds and what rpm at which it occurs. For every 1 inch of change.. you gain or lose about 3 mph for the same rpm. Would be similar to changing from a 3.00 rear gear to a 3.12 gear.. and 2 inches would be like going from a 3.00 to a 3.25 final drive. That's not what most people would call "not noticeable". A 235/70/15 tire is 28 inches. A 275/60/15 tire is also 28 inches. A 255/65/15 = 28 inches. Even a lowly 235/70/14 is 27 inches. All these tires fill the wheel-wells of our cars quite nicely and add to the hot rod look. Personally speaking.. I don't like a low profile tires unless they're sitting on rims at least 2 sizes larger than stock simply because they don't fill out the wheel-wells enough to get rid of the daylight. I also think you guys may seriously underestimate what a 17 year old kid gravitates towards when it comes to bang for buck of a gear swap. Going through all the trouble and expense to go from a 2.79 to a 3.00 would likely not satisfy most people under 20 and leave them feeling gypped. Torque multiplication is worth every penny when done right and can be leveraged through tire diameter and/or gear swaps. Also.. rpm alone is not what makes gas mileage go down the tubes. Efficiency @ a particular rpm(BMEP) has much to do with final mileage. CUBIC INCHES has a big impact on fuel requirements as well and 302 of them in well tuned fashion can easily get near 20 mpg in a light car even with these dreaded 3.55's. If it can't come close?.. I always keep on tuning until it does. Upping compression also helps efficiency in a big way.
This thread got up my curiosity. I knew that I had a Posi Unit in my 71 Maverick when I bought it but I did not know what. I was planning on using a new C4 with a Stage 2 shift kit that I own or else a 4 Speed top loader that I own. AFter checking my numbers I see that I have a 8.8 Montaineer 3.73 rear end. I am now going to have to sell my C4 and my top loader and find a T5. My engine is a new 360HP 302 for street driving and I don't want to drive it all wound up on the country roads. I definitely decided I want an overdrive with this rear end thanks to this thread. The 8.8 rear end is a cheap one to run and if I have to replace it then it's easy.
'Sorry, but no way in hell will anyone get 20mpg out of a 302 with 3.55 gears at highway speeds. I've experimented with different tire diameters on my car, and the difference in RPMs is miniscule. A 26-inch tire fills the wheel opening on a Maverick. These cars do not have very big wheel arches. You can see how member "Grabber GT" modified his wheel arches for those big wheels & tires (and yes, it does look good). If someone wants 3.55s, that's what they should have, but if they don't know what they're in for, they could be disappointed. I have run 2.79s (my original ratio), 3.55s, and 3.40s. I like the 3.40s the best. Of course if I had a overdrive tranny, I'd probably like 3.70s or 3.80s.
You'd love 'em, with the common .68 O/D, final ratio is 2.52 with 3.70 & 2.58 with 3.80.. 4.11 x .68 equals 2.79... Here's a chart that list RPMs for common gears and tire height... http://www.metropartsmarket.com/rearend/ratio.html Note final ratio with O/D will require a little figuring but the 32% mentioned is .68... Far easier to multiply by percentage remaining(.68) vs .32 then subtracting from ratio... Either method will produce same answer...
I run to 3 89 9.0 inch with 26 inch tall tires run about 2800 rpms 55 just around town then to the strip
Okay, lazy sunday in garage. Reading old post and ran into this. Texasbb14 i,d love to know what you ended up doing?
Ike, I have come a long way in these 6 years haha. Had a lot of help from other members and from my father-in-law who also has a passion for cars(restoring his 1968 Olds 442 Sport). Worked out a few great deals with some people and here is the car as it stands now. 1970 Ford Maverick 5 lug - all around disk breaks 255/60/15's on the back 225/60/15's on the front New Radiator Electric Fan Rebuilt 302 with a mild cam Edelbrock 600 Carb Original Exhaust Manifolds from a 1973 Maverick Stainless Exhaust Flow Master Super 40's (or super 44's. Can't remember) Rebuilt C4 Trans Rebuilt Ford 8" Rear End. (Had the 2.79 in it. Ended up switching it out my self for the 3.25. After reading everyone's thoughts on it I did not want to go with something to high that would leave the car screaming on the hwy. I wanted to get something that would give me a little more power but not to the point of sacrificing gas mileage and comfortably at highway speeds) I have bucket seats that new to be recovered and put in and replace the door panels. I have the driver side of the card sanded and primed. Hoping to get it painted this year at some point.
Texasbb14 Awesome update! Your setup is sweet including gear selection. An all around balanced car is what its all about. Well done Sir!
