I have a F100 with a 350/350 and would like to increase my mpg. Used mostly for freeway driving. My question is What is the best overdrive for easy freeway crusing. I'd prefer something without electrical hookup (if possible) What are length dimensions of OD compared to my 350. What makes and models did these OD's come in. What should I avoid when searching for OD. Thanks for any suggestions.
700r4... there are good years,,,, After 87 or 88 but before 93 ish? avoid first generation 700r4's I under stand size depends. I was told that they come roughly the same size or bigger then the 350. I have a 700 r4 and am still checking the size and if I need a new shaft. I guess it depends on what it came out of
Do a search for the 700R4 on here. You'll find a wealth of information on OD transmissions. Here's a link to one of the best http://www.jalopyjournal.com/forum/showthread.php?t=775908&highlight=700r4
You could always use a Gear Vendors Overdrive. They attach to either the rear end or transmission. They also will handle a boatload of HP.
The 700R4 is not bigger than a TH350, per-se, just longer. Be aware, there are several tail shaft/case configurations. The Corvette one does not have a place to put a conventional transmission mount, and the big wagons (and some others) got a longer output shaft and housing.
Don't overlook or under estimate the GM 2004R. Early models, same as with 700R4, had weak parts, but later versions and those rebuilt by good shops are very serviceable units. Same length as a 350, rear mount is farther back on case. Has 2.74 first gear vs 3.06 for 700R4. OD ratio is about the same .....about .70. Ray
2004R is a great choice! maybe better trans than the 700r4!! Above says the trans X member is back further.......6 5/8 inches back. same drive shaft as your 350
http://www.hemmings.com/mus/stories/2006/01/01/hmn_feature9.html GM TH200-4R transmission 1981-'88 Buick LeSabre and Electra RWD 1981 Century 1981-'87 Regal 1981-'90 Cadillac Fleetwood, Deville and Brougham 1982-'90 Chevrolet Impala and Caprice 1981-'88 Chevelle, Monte Carlo, Malibu and El Camino 1984-'87 GMC Caballero 1982-'90 Olds Delta 88, 98 and Custom Cruiser 1983-'88 Olds Cutlass 4-4-2 and Supreme 1983-'89 Pontiac Bonneville, Parisienne and Safari Wagon 1981 Pontiac Firebird with 301 1984-'87 Pontiac Grand Prix Shift ratios for this transmission: 1st 2.74:1; 2nd 1.57:1; 3rd 1.00:1; 4th 0.67:1
I would use a 200 or a 700r, but the 700 would be my first choice The over drive is a must for mileage and driving on the hi-way
1987-93 2004R is the best donor and has the good later lubrication upgrades and is more compact and is the same length as your 350, so no driveshaft mods are needed but you will have to relocate the crossmember.For better reliability and performance get this:http://www.oregonperformancetransmi...t.mvc?Screen=PROD&Product_Code=TRG-200-4R-HD2 For the TV cable if you are running a Holley or Edelbrock Carb get the LOKAR kit TV cable adjustment in either trans is critical.
I was thinking about getting an overdrive, but after figuring out how much I actually drive my old car, the estimated gas savings were around $600 a year and to get a decent overdrive would have been close to $1200 so I decided to eat the fuel cost every two years rather than pay the $1200 up front plus all the work... driveshaft shortening, new yokes, cooling lines, etc. I sold the car after three years anyway and now I have a bigblock so mpg isn't even something I consider, lol.
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