350 trans and converter?

seeker · Post by **seeker** » Tue Jan 06, 2009 10:20 am

for those of you that will be using Bill's th350 adapter with the 4g63 what converter are you going to use with 3:54 gears?

i'm thinking 9.5 2800-3200 non lockup

what are your thoughts?

89coltgt · Post by **89coltgt** » Wed Jan 07, 2009 7:54 pm

The stall speed really dpends on you setup and what you are doing. I will be running a neil racing 2800-3400 converter and a freshened up th350 for now. Once I have time to build a block, I may go to a powerglide or th400, with a brake and a more aggresive converter.

seeker · Post by **seeker** » Sat Jan 10, 2009 12:13 am

i'm in the same boat, would like a th400 but will go with the 350 for now since i have one on hand.

Bill Hincher · Post by **Bill Hincher** » Sat Jan 10, 2009 9:20 am

the TH 400 is a bit different from the rest of the GM transmissions, from what I can tell, the 400 needs 3/16 in free travel end play and the rest only need 1/8
I put enough material in the adaptors to build them either way , but I need to know what you have before I cut it

seeker · Post by **seeker** » Sat Jan 10, 2009 1:24 pm

i will go with the th400 then....Bill do you have a final price?

Bill Hincher · Post by **Bill Hincher** » Sat Jan 10, 2009 2:50 pm

I sent the coupler out to see what a local machine shop will charge me , I enjoy the build but not the grind .;o)

at this point I am still at about $300.00 or less

seeker · Post by **seeker** » Sat Jan 10, 2009 3:04 pm

i'l also need a modified manifold so i guess i will get them both at the same time. send me an addy to send you my mani, thanks Bill

Morpheus · Post by **Morpheus** » Sun Jan 18, 2009 3:21 pm

Bill Hincher wrote:the TH 400 is a bit different from the rest of the GM transmissions, from what I can tell, the 400 needs 3/16 in free travel end play and the rest only need 1/8
I put enough material in the adaptors to build them either way , but I need to know what you have before I cut it

As I said before in the adapter thread, GM's spec for the "E" dimension is 21.67mm +/- 1mm. This is the dimension from the rear of block/front face of trans to the pad on the convertor. This applies for all V6, V8 (big and small block) and the inline 6 up through mid 90s. LSX series engine changed all that. That would define where the converter side of the flexplate should be. It's the same for all turbo series trasnmissions, powerglide, and 4L60/65/L80. The free travel will be what it is, based on the relation of the face of the trans and flexplate. If you build the adapter plates to that dimension, the free play will fall out with you haveing to make different adapters. One adpater set fits all.

I work within GM powertrain, specifically, development in the transmission group.

Bill Hincher · Post by **Bill Hincher** » Sun Jan 18, 2009 3:41 pm

you know ?
I went through all the crap of trying to find a metric numbers for everything on the GM trans, yeah, they list metric numbers, but all they did was take existing US standard demensions and converted them to Metric ( broken) numbers IE 1/2 becomes 12.70 mm , the factory never retooled or changed demensions into whole metric numbers, so I figure I would stay with US standard numbering system to match the back of the original OEM small block Chevy, including the torque converter free travel demensions listed for the repective transmissions
It worked for years that way and I will stay with it

77amc · Post by **77amc** » Mon Jan 19, 2009 9:44 pm

In addition, the 400 needs a lot bigger slip yoke than the rest of the GM trans and are about 80.00 new and then of course you will need to adapt the drive shaft to that slip yoke. ANd pound the tunnel for the width.

The 400 does have the most parasitic drag though. (cost more in HP just to use it) BUT it's going to be a stronger trans

I"m thinkin of using a 2004r overdrive w/a 2400 stall behind a 2.4turbo..
(when I ever get to that point)

E

Morpheus · Post by **Morpheus** » Fri Jan 23, 2009 8:37 pm

Bill Hincher wrote:you know ?
I went through all the crap of trying to find a metric numbers for everything on the GM trans, yeah, they list metric numbers, but all they did was take existing US standard demensions and converted them to Metric ( broken) numbers IE 1/2 becomes 12.70 mm , the factory never retooled or changed demensions into whole metric numbers, so I figure I would stay with US standard numbering system to match the back of the original OEM small block Chevy, including the torque converter free travel demensions listed for the repective transmissions
It worked for years that way and I will stay with it

Where are you getting "the torque converter free travel dimensions listed for the respective transmissions"? You speak as though you are using some reference. What/where is it? Prior posts here and in the other thread, you posted as though you were guessing or using your best judgement.

The point in all this is, if built to the correct dimension, the crank spacer you make doesn't need to be modified to run a turbo 350 vs a turbo 400. They should have the same dimension.

I don't know where I went wrong here, but I'm picking up on a lot of negativity in reponses from you. I'm merely trying to help. I take it, that your machinery is standard, not metric. So, take the 21.67 and divide by 25.4 and it's standard. (hair under 55/64ths, 55/64ths would be within the spec )You're wondering "what the dimension should be?" There it is. Again, I'm trying to help. Hell, had you asked, I could have given you the bolt circle and hub dimensions that the flywheel locates on. Exact.

Obviously you're a smart guy and talented in machine work. I'm not questioning the quality of your work or your ability. I'm going to buy a setup here soon myself and I'm sure it'll work fine. I just thought in your tuning of the final product, you might want to use the number defined by GM.

Bill Hincher · Post by **Bill Hincher** » Fri Jan 23, 2009 8:56 pm

I spoke to the tech department at TCI here is the chart

http://www.tciauto.com/Products/TechInfo/FAQ.asp#4

89coltgt · Post by **89coltgt** » Fri Jan 23, 2009 9:14 pm

My question would be then when you buy a converter, they are listed for a both a th350 and th400, are the mounting pads set up to where they would have to be shimmed when using the th350?

Morpheus · Post by **Morpheus** » Fri Jan 23, 2009 9:26 pm

Bill Hincher wrote:I spoke to the tech department at TCI here is the chart

http://www.tciauto.com/Products/TechInfo/FAQ.asp#4

Thank you for the information.

I don't know what else to say other than GM's spec is different. From the company that built/designed the trans.

Morpheus · Post by **Morpheus** » Fri Jan 23, 2009 9:34 pm

89coltgt wrote:My question would be then when you buy a converter, they are listed for a both a th350 and th400, are the mounting pads set up to where they would have to be shimmed when using the th350?

From GM's prospective, no. The adapter should be the same, in the same location, regardless if it's a turbo 350, 400, or powerglide.

Bill Hincher · Post by **Bill Hincher** » Fri Jan 23, 2009 10:00 pm

the answer is in the depth of the fingers in the pump,
if you read the information correctly, the 3/16s figure is measuring the depth of the convertor away from the face of the transmission,
the extra 1/8th is because the fingers of the convertor driving the pump is shorter, it has no bearing on the distance to the pads on the flywheel

89coltgt · Post by **89coltgt** » Fri Jan 23, 2009 10:21 pm

Bill Hincher wrote:the answer is in the depth of the fingers in the pump,
if you read the information correctly, the 3/16s figure is measuring the depth of the convertor away from the face of the transmission,
the extra 1/8th is because the fingers of the convertor driving the pump is shorter, it has no bearing on the distance to the pads on the flywheel

That would also mean that the converter will be 1/16" difference between the th350 and 400 as far as free play goes(which I know that you know this Bill

). That said, what do the chevy guys do when they swap back and forth from a 350 to a 400? I am assuming the converter will be shimmed 1/16" when using the th350 trans compared to the 400.

I myself will be running a th350 first but I may switch to a 400 when the power is there, so I am wondering if it would be wise to have my hubs made with the extra 1/16" machined out of then in order to work with the th400, and shim the converter when I have the th350 in there or is that a bad practice to shim that much?

If I am not thinking correctly here, someone please let me know

Bill Hincher · Post by **Bill Hincher** » Fri Jan 23, 2009 10:46 pm

jegs makes the shims available and there are longer flex plate bolts, but I dont think you would need them, I do see the 350 and the 400 troque convertors listed as the same unit, the only thing I can say is the 1/8 the shorter fingers should be no problem driving the pump