I've got a 71 l48 that i want to work on, starting with the transmission and torque converter. She's packing about 400hp, so i need something with a fair amount of beef in it. I've selected the B*M torque master 2000 as my torque converter, but now i need a transmission. I now have an old, decrepid, and leaky TH400. I'm looking to find something that robs me of less HP, and has taller gears throughout than the factory tranny. Any suggestions???? Tks,

Brandon

The TH400 was a good unit. One of the best. But with what you are looking for you may want to check out the TH700R4. It's used in the newer Corvettes, and it's a 4 speed with an overdrive. Good on the bottom end, better mileage on the highway.

Ken Styer

I've looked into a 700, but i'm just not willing to pay that much. It would be so much cheaper to drop a 350 or 400 in. Not just the trans. price, but all the modifications that would need to be made as well. Couple of q's: Does the 350 require less HP to turn than the 400?? Are the new 350's/400's any more efficient than the old ones?? Does anyone make a 350/400 that comes with higher gears pre-installed? Tks,

Brandon

I've been surfing now for hours. I've been looking over and over at the same stuff, and i just can't make up my damn mind!! I've come to the reality that an overdrive would be more practical, seeing as i drive the vette a good 10000-15000 miles a year. Bowtie seems to have a good selection available. Any idea what else i would need to install a 2004r into a 71 l48? Or if anyone has done it before, roughly how much it would cost in the end, including installation and one of there 2200 rpm stall converters? Tks,

Brandon

At my shop, we have done several th400 to th350 swaps. The th350 uses less hp, weighs less, and parts are cheap. Acceleration is noticeably quicker. 400 hp shouldn't hurt a properly prepped th350. gl

To do a 700R4 you need to shorten your driveshaft, maybe $50. It uses the same yoke. To get first gear you must modify your shifter, or buy the $100 kit from BowTie. You must modify your crossmember or buy the super sweet $200 one from BowTie. Other than that all you need is the transmission. Get it from BowTie or source it locally. Get at least an 89 if you get it locally, they have better parts. I love mine, it is worth the hassle to get that overdrive and first gear.

i would think that gm put the 400 in the higher output cars for a reason, sure it might weigh a little more, but the point is, they are practically bulletproof if you maintain them. The newer 4 speeds might be good for mileage, but i guarantee that i'm not the only one who has seen many, many of them go out of pickups, and cars with less than 250 hp. I might sacrifice a little mileage for the reliability of the 400. That or i will install a manual 5 speed some day, just my 2 cents.

Agreed the TH400 is the strongest of the bunch. The TH350 has a lower first gear than the 400, so it gives a better launch. Some of the 4 speeds also have a lower first than the 400. Choices, choices.....
I have a TH400 and plan on keeping it.
Just me.

Ken Styer

I have a BTO Level2 200r4 love it
http://hometown.aol.com/bmclau5079/page4.html