SBC 350 / TH350 / 3.50:1 ???

[LarrySmith]

Googling it turned up more than 60 cars of various descriptions using this combo before I stopped counting.
Why do it?
My own experiences with similar are mostly my uncle's C-10s, but this combo doesn't do anything well.
My uncle's 2-tone '85 is the same except 3.42:1 rather than 3.50:1, on 275/60R15s, he has a nearly identical blue '86 long-box with a 700R-4 and 3.08:1, also on 275/60s. The '86 pulls better in first, though the '85 does hold first gear for another few MPH. Then the '86 is always the only choice for interstate trips. It doesn't like hills or headwinds, but the 3.42s would fix that. And pull even stronger in first. The 700 has a big jump from 1st to 2nd on paper, but in real driving, it's no issue. Not ever.
So why the TH350?

 

[Swampdog]

Less Expensive ( on the order $500 or so) , easy installation, short length(remember you will have a drive shaft about 24 inches long). With 700R you can wipe out a transmission real quick with a miss-adjustment on the kick down linkage.
Most T Buckets were not built for gas millage and high speed interstate cruising is not their forte.

 

[Spanky]

I agree with Swampy. I run a 350/350 with 3.08 rear gear. The ratios in the TH 350 suit my driving to a "T" (pun intended!) Remember, these cars weigh less than 2,000 lbs so acceleration is quick. And at 60 MPH in top gear I'm only turning 2,350 RPM (26.5" rear tires).

 

[Indycars]

Guess I have a little different perspective. The 200-4R is essentially the same
length as the TH350 and has the same spline count. Therefore a driveshaft change
is not needed. Has better gear spacing than the 700-R4. I have a 3.70 rear gear and
31 inch rear tires, I'm only turning 1850 RPM at 70 mph. Have gotten as high as
20 mpg on the highway at 65 mph.

 

[2old2fast]

Pull 1 of those sub 200 hp engines out of the truck & build it w/some decent compression , good flowing heads , a cam that actually works , after market manifold w/ carb or efi ,then you'll be producing 300-400 hp & see how the truck runs , then put that engine in a 1700 # T & see what you think....

 

[Gerry]

350/350 has a certain 'ring' to it. Ratios really dont count for much with 480ft/lbs in a bucket. Could take off in 3rd and still beat the crap out of most things.



Case is kind a pretty as well
Course JMHO

 

[LarrySmith]

Less Expensive ( on the order $500 or so) , easy installation, short length(remember you will have a drive shaft about 24 inches long). With 700R you can wipe out a transmission real quick with a miss-adjustment on the kick down linkage.
Most T Buckets were not built for gas millage and high speed interstate cruising is not their forte.

$500?!!! Pick-N-Pull asks the same $85.99 for any transmission.

 

[LarrySmith]

Guess I have a little different perspective. The 200-4R is essentially the same
length as the TH350 and has the same spline count. Therefore a driveshaft change
is not needed. Has better gear spacing than the 700-R4. I have a 3.70 rear gear and
31 inch rear tires, I'm only turning 1850 RPM at 70 mph. Have gotten as high as
20 mpg on the highway at 65 mph.

That worries me. I know of a '78 Camaro with a 350 / 700R-4 / 3.08:1 / 235/60R15 that does 24.3 MPG at 65 MPH at 1860 RPM. Is the drag really that bad on T-buckets?

 

[tfeverfred]

That worries me. I know of a '78 Camaro with a 350 / 700R-4 / 3.08:1 / 235/60R15 that does 24.3 MPG at 65 MPH at 1860 RPM. Is the drag really that bad on T-buckets?

I'm not sure how aerodynamics effects mileage, my problem with that was my right foot. But as far as drag goes, these cars have the aerodynamics of a brick. But again, being all swoopy and streamlined is NOT what most street driven Hot Rods are about.

The salvage yards here rarely have a 350th. VERY rarely..... like no mas, but a core can usually be found on Craigslist for about $100.

 

[tdkkart]

Is the drag really that bad on T-buckets?

Stand in front of one and look at it, EVERY forward facing surface, except for the driver's face, is dead flat.
So a wall, 4ft+ wide by 5ft+ tall, being shoved down the road. Zero aerodynamics............

 

[tdkkart]

Pick-N-Pull asks the same $85.99 for any transmission.

Looks like there's approx. 14 Pick-N-Pull locations across the entire country.........

 

[roadmonster]

I like TH350s because to me they shift like a dream. Light foot= short shifts, heavy foot =tire-chirping kick. They never seem to be in the wrong gear.

 

[fletcherson]

Th 350 short shafts are not as easy to find around here. A burnt up core is $100.00. I haven't tried pic n pull, the one here rotates their stock and there are rarely any older cars there. The 350 is a simple, solid, tried and true trans with many available aftermarket goodies. I personally prefer standard shift, but the th350 is a good one.

 

[RPM]

700 is my go to trans, low first gear and great OD keeps those RPMs low at higher speeds. Couple that with a 3.73 rear and you got a hot rod. You know you multiply the trans first gear ratio X the rear end ratio so 3.06 x 3.73= 11.41 first gear leaving the stop light vs a 350 trans 2.56 x 3.08=7.76 a big big difference in low end. Now do the high gear thing .75 x3.73=2.79 highway cruising, keeping the RPMs lower. The 350 trans is direct in high gear so it is just 3.08
Also with the 700 you get to run a lock up converter An inexpensive stall converter that locks up is one from the 4 cyl S-10 truck. It will stall about 2800 behind a good 350-383 engine.

We had a 383 stroker in a 4 seat bucket some years ago lots of power and it would get 25 MPG cruising the interstate.

 

[Spanky]

700 is my go to trans . . . you multiply the trans first gear ratio X the rear end ratio so 3.06 x 3.73= 11.41 first gear leaving the stop light vs a 350 trans 2.56 x 3.08=7.76 a big big difference in low end.

You're right. Ron. But even so, I have to roll into the throttle in my bucket to keep the wheel spin to a minimum. If I just nail it off the line, it just sits there and moves sideways!

 

[Indycars]

That worries me. I know of a '78 Camaro with a 350 / 700R-4 / 3.08:1 / 235/60R15 that does 24.3 MPG at 65 MPH at 1860 RPM. Is the drag really that bad on T-buckets?

Looks like you got your answer about aerodynamics.

My TBucket is not built for gas mileage, but the 200-4R with a 0.67 4th gear allows
it to get pretty decent gas mileage. The Crower hydraulic roller camshaft specs are
236°/240° duration at 0.050" and .555/.560 of lift.

 

[Swampdog]

My T Bucket get an honest 14.5 MPG figured over 1000 plus miles.
See decal on the bottom of the bed ( in silver)

 

[Gerry]

Th 350 short shafts are not as easy to find around here.

Or anywhere. I do work for a trans shop and still had to pay top $ for a short output shaft. Took me 5 months to source the short tail housing to go with it and it had the bigger speedo take off. Eventually I found a shorty with the small speedo take off, but it was hard work.

Now talk PGs. They are getting like rocking horse sh*t. Got 3 in storage, just waiting for the guys who needs one to come up to my selling price.

 

[Screaming Metal]

---So why the TH350?---
Because with a minimum of work, can easily stand up to 700 Normally Aspirated Horses, 500 pressurized HPs, is almost as durable as the turbo400, takes about 35 horsepower less to launch than TH400, Plus you can hammer on it that'll destroy all the newer OD Trans. Plus its a old HotRod Standard.
I'm with RPM, a 700 is a great trans.....Its not like you'll get your hi-perf T to hook up well enough to do any real damage....if everything is correct....

 

[Screaming Metal]

Heres a idea, get your stout 350, buckle it up to a good stout 350 turbo, gear it to where you have a nice cruise speed without too much rpms. Theres online calculators for tire size, gear ratios, weight, and rpm to road speed....
Yes, a OD trans lowers your engine rpm. If you just geared correctly to start with....You'll still have plenty of power to stand on it when you need to and blow away a good 98% of all street cars....