TH350 in a C4?
Racer
Joined: Jun 2006
Posts: 461
Likes: 0
From: ilion ny
well burnett that was greatly informational and im not no expert by any means i just know by word of mouth that the th-400 was a better transmission (at least stock transmission anyways) i didnt realize the amount of work that would be involved with it but im glad someone with experience chimed in and informed us all what is needed and easier either way thanx for ther input even though im not considering this its always good to learn a thing or 2
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
I have been running a T350 for some time now.
Call up Carl at www.rosslertrans.net and tell him that I sent you. He got me all the necessary things I needed for mine, and TRUST ME; you will NOT find someone that builds a BETTER transmission than this guy.
WE have a T350 holding up fine behind my father 555CI chevelle, making well in excess of 800hp. Doing this at 3700lbs.
For a little over 1200 dollars you can have a t350 that you can abuse till the cows come home or you get tired of racing, if there is such a thing
Call up Carl at www.rosslertrans.net and tell him that I sent you. He got me all the necessary things I needed for mine, and TRUST ME; you will NOT find someone that builds a BETTER transmission than this guy.
WE have a T350 holding up fine behind my father 555CI chevelle, making well in excess of 800hp. Doing this at 3700lbs.
For a little over 1200 dollars you can have a t350 that you can abuse till the cows come home or you get tired of racing, if there is such a thing
Instructor
Joined: Apr 2014
Posts: 106
Likes: 1
From: Shreveport Louisiana
If you build the TH350 they can be as strong as "most" TH400's (all except the full-tilt $5k jobs like I have in my car). And for most applications they're better, here's why:
-Their gear split is better, unless you upgrade first and second in a 400 the split is too far apart and the 400's first gear to high at 2.48.
-The 350 is a smaller and lighter transmission and, in racing, ounces make pounds!
-The 350 is a MUCH more efficient transmission with less parasitic loss...As much as 12% less in some cases.
-For a C4 application the 350 is more practical and easier to install (just a simple spacer away with your supplied 700R tailhousing).
Now, having said that I choose to run a 400 that's a full race piece: it has 300M input and output shafts, billet pump, drum, and planetary as well as upgraded ratios in first and second. It will also hold 2500 hp and while I only make between 1250 and 1500 (depending on how big a pill I put in it) I believe in overkill when it comes to a full-on race tranny. However in a C4 application they're a bitch to install if you wanna do it REALLY right. You can build a tailhousing adapter and attach to the c-beam but that's really not the method I choose in a full-on race application. Since there's no real crossmember you put the load on the pinion nose of the diff case. When you hit the tires the tailhousing tries to move upwards the just like the pinion climbing the ring gear. As stout as that c-beam looks, when you're capable of REALLY hitting the tires it will MOVE. You ought to see the buckles in the one out of my car from 5500 rpm stick launches!!! If there's any slack whatsover, that exacerbates the problem and with the diff nose in a bind, it BREAKS! The secret to racing a SERIOUS C4 with the IAS, I'm totally convinced hinges on two things:
1) An automatic transmission, even one with a huge stall and a t-brake doesn't shock as hard as a manual.
2) A REAL transmission crossmember to take the load off of the diff.
Now, that may have seemed like it got off subject, but my feeling is with a Turbo 400 the best way to use it in a C4 is by fabbing a real tranny crossmember and that involves cutting the floors right in front of your seats...Just a slot, but still the floor is cut with a nice 1.5" piece of chromoly tubing "just" poking up through the floor. It is my opinion that most people that want to can the 700 (or whatever else) and don't want to cut up their cars and aren't deep 9 second cars would be better of with a Turbo 350 due to the better availability of the adaptor and the fact that you can use your stock tailhousing and the stock c-beam.
I've actually built a tubular c-beam to adapt the 400 to the C4 but my prototype doesn't allow easy removal cuz I'm a dipsh!t and wasn't thinking about in car removal! I've since revised it and solved that problem but I still think with the 400 (and honestly, the 350 if you plan on going in the 9's pretty deeply) should have a crossmember. I'm actually in the midst of triangulating mine even further with the addition OF a torque arm with the crossmember...But instead of being attached to the tailhousing it will attach to the crossmember; that way you have a nice "spine."
-Jeb
-Their gear split is better, unless you upgrade first and second in a 400 the split is too far apart and the 400's first gear to high at 2.48.
-The 350 is a smaller and lighter transmission and, in racing, ounces make pounds!
-The 350 is a MUCH more efficient transmission with less parasitic loss...As much as 12% less in some cases.
-For a C4 application the 350 is more practical and easier to install (just a simple spacer away with your supplied 700R tailhousing).
Now, having said that I choose to run a 400 that's a full race piece: it has 300M input and output shafts, billet pump, drum, and planetary as well as upgraded ratios in first and second. It will also hold 2500 hp and while I only make between 1250 and 1500 (depending on how big a pill I put in it) I believe in overkill when it comes to a full-on race tranny. However in a C4 application they're a bitch to install if you wanna do it REALLY right. You can build a tailhousing adapter and attach to the c-beam but that's really not the method I choose in a full-on race application. Since there's no real crossmember you put the load on the pinion nose of the diff case. When you hit the tires the tailhousing tries to move upwards the just like the pinion climbing the ring gear. As stout as that c-beam looks, when you're capable of REALLY hitting the tires it will MOVE. You ought to see the buckles in the one out of my car from 5500 rpm stick launches!!! If there's any slack whatsover, that exacerbates the problem and with the diff nose in a bind, it BREAKS! The secret to racing a SERIOUS C4 with the IAS, I'm totally convinced hinges on two things:
1) An automatic transmission, even one with a huge stall and a t-brake doesn't shock as hard as a manual.
2) A REAL transmission crossmember to take the load off of the diff.
Now, that may have seemed like it got off subject, but my feeling is with a Turbo 400 the best way to use it in a C4 is by fabbing a real tranny crossmember and that involves cutting the floors right in front of your seats...Just a slot, but still the floor is cut with a nice 1.5" piece of chromoly tubing "just" poking up through the floor. It is my opinion that most people that want to can the 700 (or whatever else) and don't want to cut up their cars and aren't deep 9 second cars would be better of with a Turbo 350 due to the better availability of the adaptor and the fact that you can use your stock tailhousing and the stock c-beam.
I've actually built a tubular c-beam to adapt the 400 to the C4 but my prototype doesn't allow easy removal
cuz I'm a dipsh!t and wasn't thinking about in car removal! I've since revised it and solved that problem but I still think with the 400 (and honestly, the 350 if you plan on going in the 9's pretty deeply) should have a crossmember. I'm actually in the midst of triangulating mine even further with the addition OF a torque arm with the crossmember...But instead of being attached to the tailhousing it will attach to the crossmember; that way you have a nice "spine."-Jeb
