Ideas on my drivetrain
Thread Starter
Pro
Joined: Mar 2004
Posts: 686
Likes: 0
From: Southeast
Ideas on my drivetrain
I have a 71 with a 350 that's had some work done to it. Here's what:
-Bored .020 with flat-tops
-Bottom end supports 6200 RPM
-Trick Flow aluminum 64cc 23 degree heads
-CR somewhere around 10.5:1
-Comp Cams .462/.482 with 219/229 at .050 duration
-Edelbrock Performer intake with Edelbrock 600 CFM carb which I plan to get rid of both in the near future (only limiting factor)
-Hooker Headers
I'm about to have a lift installed in my shop, and I've been waiting on it to do work on my transmission which leaks fairly bad. Also, the TC has been going out for awhile and doesn't work well with my cam anyway. My question is this: should I rebuild my TH-400 with a good TCI rebuild kit with a shift kit or should I just install a 200-4R or 700R4? Will my cam and engine set-up work well with an overdrive transmission? I still have the 3.08s in the rear and will probably take them to someone to upgrade to maybe 3.73s or whatever you all think will work best if I go with the overdrive tranny. Thoughts?
-Bored .020 with flat-tops
-Bottom end supports 6200 RPM
-Trick Flow aluminum 64cc 23 degree heads
-CR somewhere around 10.5:1
-Comp Cams .462/.482 with 219/229 at .050 duration
-Edelbrock Performer intake with Edelbrock 600 CFM carb which I plan to get rid of both in the near future (only limiting factor)
-Hooker Headers
I'm about to have a lift installed in my shop, and I've been waiting on it to do work on my transmission which leaks fairly bad. Also, the TC has been going out for awhile and doesn't work well with my cam anyway. My question is this: should I rebuild my TH-400 with a good TCI rebuild kit with a shift kit or should I just install a 200-4R or 700R4? Will my cam and engine set-up work well with an overdrive transmission? I still have the 3.08s in the rear and will probably take them to someone to upgrade to maybe 3.73s or whatever you all think will work best if I go with the overdrive tranny. Thoughts?
Le Mans Master
Joined: Dec 2000
Posts: 5,386
Likes: 2
From: San Angelo TX
Ditch the TH400 and go with the 2004R. I've never heard anyone say anything negative about them and the OD will completely change the drivability of your car. That's the route I'm going to take when my TH400 craps out on me.
As for gears. Think of it like this. The C4 came with a 3.08 "performance" rear gear and a .70ish OD gear which kept RPMs low and MPG high while providing nice scoot. Most people upgrade that to a 3.45 or 3.73 so I would go that route if wanted. I'm planning on keeping my 3.36 when I go with the 2004R as a nice compromise between performance and economy (it's going to be daily driven).
Hope that helped a little. I'm sure there are plenty of others more knowledgable that may think otherwise though.
-Justin
As for gears. Think of it like this. The C4 came with a 3.08 "performance" rear gear and a .70ish OD gear which kept RPMs low and MPG high while providing nice scoot. Most people upgrade that to a 3.45 or 3.73 so I would go that route if wanted. I'm planning on keeping my 3.36 when I go with the 2004R as a nice compromise between performance and economy (it's going to be daily driven).
Hope that helped a little. I'm sure there are plenty of others more knowledgable that may think otherwise though.
-Justin
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
It really depends on how you will be using the car/motor. If you plan on working it hard...a lot....ANY of the transmissions you mention should be beefed up from standard configuration. The 400 will handle the most HP, as is; but it has only 3 speeds and no lockup function; and the overdrive and lockup function will be important if you will be driving regularly..especially at highway speeds. If you really don't care much about the highway driving 'thing' and the cost of fuel isn't a significant consideration, just upgrade the 400--new and stronger converter better clutch plates, etc. and stick a 3.55 rear end on it.
Thread Starter
Pro
Joined: Mar 2004
Posts: 686
Likes: 0
From: Southeast
It really depends on how you will be using the car/motor. If you plan on working it hard...a lot....ANY of the transmissions you mention should be beefed up from standard configuration. The 400 will handle the most HP, as is; but it has only 3 speeds and no lockup function; and the overdrive and lockup function will be important if you will be driving regularly..especially at highway speeds. If you really don't care much about the highway driving 'thing' and the cost of fuel isn't a significant consideration, just upgrade the 400--new and stronger converter better clutch plates, etc. and stick a 3.55 rear end on it.
Drifting
Joined: Jul 2003
Posts: 1,253
Likes: 1
From: East China MI
Whatever trans you deside on, a good starting point for a street car is to get about 10 to 1 in first gear. Multiply the trans first gear ratio by the rear gear ratio. If you get lower than 9 you will be weak from the lights. If you get over 11 you will rev up faster and start to get that "creeper gear" sensation. This is just about drivability, all out performance is another topic. The OD is always a good idea!
