Howdy boys- As my car is being towed home from Columbus Texas after breaking down again I am reflecting on my 350 mile road trip and the thought of maybe switching from my Turbo 350 trans to a 200R??? I would like to get a few opinions on this matter from guys that have run across the same issue. I currently have the following drive train: #1- 1986 SBC 305 out of a Monte Carlo (Rebuilt) #2- 1967 Camero rear end with 308 gear ratio #3- Firestone 670's 15" #4- Turbo 350 Trans I know that 3K rpm's is not bad but I was just thinking that if I go with the 200 I would have better Gas mileage and less stress on the motor. I plan on doing a TON of hwy driving and that is really the only reason I am giving it thought. Any input is welcome on this. Sam
Very good choice is the 200R. Bolts directly in place of 350 and can be made bullet proof. When my 350 gives up I will be switching over.
The 200 will reduce your gear ratio about 30 per cent .... SO 3.08 minus 30 per cent = 2.15 I think that is too high ... A lot of the Monte Carlo SS coupes had the 200 transmission but most were 3.42 or 3.73 rear end equipped. With a fairly tall 15 inch tire. A 3.73 minus the 30 per cent is 2.61 That would be a improvement ...... I have a 700R4 in my 32 3W ... with a 3.50 rear ratio. It is almost too high for my engine. I need a 3.70 or even a 3.89 ... in my coupe for the OD to be in the right RPM range ( IMHO )
sounds like the set up I have for my 49. 305, 65 Nova 3.08 rear and a 700R4. I am going to run 14" 60 series tires, so my tires will be much shorter than yours. I did the math and will be only spinning like 1800 RPM's at 70 in OD. this is not good. I have a Ford 8" with 3.43 gears I may swap out. how fast are you going at 3000 RPM? somewhere on the interweb is the formula for trans/rear gear / tire size and what RPM you will be spinning at certain speeds. I think I googled "automotive math" when I found it.
Without a doubt,go with the 200R4.Check out the Art Carr website for some 200R4 goodies to beef it up as needed.You will want an '87-92 core for your build as these years had the internal upgrades.
You didn't say what broke, but the T-350 is ab out as reliable as auotmatic trannys get. The 200-4R will fit into about the same space. The 700-R4 is stouter than the 200 and a bit larger. A 3.08 gear really ain't enough gear to be useing overdrive in my opinion. Some do but the tranny seems very "busy" when running around the speed limit to me. 3.42 is about the tallest gear that the factories put behind an OD. Thousands have found the SBC/T-350/3.08 gear to be a great combo (even if it ain't exactly High Performance) for high way driving.
Even better... with the 30% overdrive, you could step up to 3.50ish gears and run 80 mph at 2400, which is where many folks like the motor to be. Quicker and still more efficient! Just be careful with the TV cable adjustment.
I've had some built 4L60E combos, and I liked to be under 2500 rpms at 70-75mph otherwise my gas mileage kinda sucked. 3000 rpms at 70mph will eat gas. 200R4 has a nicer first gear than a TH350 too. Best of both worlds.
I have a 200 in our ford.I pulled the turbo 350 out a few years ago. I have a 3:79 rear gear,I think the 3:08 will lug the motor when in O.D. The drive shaft will fit.you need to mod, the cross member and lock up the torque converter.The speedo even bolts up. I just think you will need to change the gear in the rear. Good luck with it russ
3.42 or 3.55 gears would work better BUT........I have an '88 C1500 with a very tired 305 TBI, fresh 700R4 and 2.73 gears with 235/75-15 tires. It won't win any drag races but it gets mileage in the high teens and gets around just fine. A good friend put a 200-4R behind a boneyard 305 with a Summit 1102 cam and 3.08's in a '63 Bel Air with 235/70-15 rear tires. Again, no drag car but it could haul 4 adults no sweat pulling 21 HWY MPG all day long. The only drawback is that if you want to switch the speedometer "drive" gear you have to disassemble the whole trans so if you decide to make a substantial gear change later you'd need to use a speedometer ratio adapter in the cable which really isn't a big deal.
I had a 38 chevy with a 305 TH350 and 3.73 rear. Loved the snap that the rear gear gave. Hated 4000rpms on the freeway. Put in the 200r4 and loved it. Didn't help too much in mileage but made the ride alot quieter on the rode. I found mine in a cadillac, they have a universal bell housing
1800 RPM at 70MPH is fine for a 305, jees my 3.8 v6 DD can pull hills at that..and if it is a huge hill I downshift. For good gas milage you want 2000 RPM or less at speed. My T56 cars with double overdrive can do 1500 RPM on the highway when cruising flat ground, downshift one gear for hills.
I would most definatly go for the 2004-R. I run one behind a sbc 350 with 3.08 and 15" 60 series tires and lockup converter. It's a little steep around town but just at 2000 at 80mph all day long. The tranny is out of an '85 MonteSS. Plenty strong since they also put them in Buick grand nationals. They will handle 400hp with not much work. Hardened shaft and bigger pump is all I did. I also put a switch on the lockup to cut it out in town if I need to. Not recommended on the highway as it will run too hot. Good luck and I know you will enjoy the ride.
I had an emergency tranny swap the day before the trip to the run to the sun......my t350 crapped the bed on Teus. afternoon, leaving on Thurs. I pulled the 350 to swap with another 350 I borrowed. Got it out, mine was a long shaft 350. Took measurements, it is the same as a 700! I happened to have a 700 rebuilt at Cook's in Cowpens, SC ready for pickup about 1:15 away, so we jumped in the truck and headed down. got the 700 in, the mounts and driveshaft are IDENTICAL to a long tail 350. Took more time to assemble the Gennie shifter than install the trans. I'm running a 350 with 3.08 and 29" tall tires. 65mph @about 1800rpm. Went frm Charlotte with a full tank of gas, made it to Myrtle Beach, cruised, shot flames, the usual, and made it to our usual stop at Sparky's in Marion. I am usually on fumes at this point, but I still have 5 gallons of gas left. My truck likes it fine @ 1800rpm. A calculator is on www.bowtieoverdrives.com, here....http://700r4.com/speedoCalc/rpmcalc.php
Unless you're running a lumpy camshaft, I'd think you could get away with an O/D and 3.08s. My '96 S10 has a 5 speed with a 30 percent O/D in fifth with 3.08 gears, and even fully loaded for Carlisle it will sail up the hills on Rt. 81 without downshifting.
One thing you have to remember when comparing a modern car with FI and computer controlled ign timing vs carbed with a centrifical + vac adv is that at low rpm the old tech won't have have as much adv as the motor could use so this makes the motor a bit doggy. If you get too aggressive with the timing you could end up with pinging at certain rpm/loads.
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