200-4R or TH350C?

[Bigblocks4life]

I would at least seriously consider the 4 speed. I have an 84 Hurst with a 455 and a 200r4 behind it that I purchased from Gearstar performance transmission and it is working great! Been in my car for about 12 years now. Mostly sees street use with the occasional pass at the track and I have had no trans. Issues. Probably will be in the $3000 range, not sure of price because it has been some time since I bought a trans from them but it is a good investment!

 

[Zippymac]

Hey everyone! This winter I'm going to be digging into my Monte ('85ss) and swapping in some stuff from my other car that was totaled 10 years ago. I'll be putting in my motor (started as a ZZ4, and now has forged internals, will have AFR heads and a cam to match, 750 Holley DP, etc.) but had some questions about the transmission.

I have the TH350C from my '84ss (along with the driveshaft, crossmember, etc.) with a 3400 stall that worked great in that car (ran 12.3@110, and that's before the new heads/cam). I'm just wondering if I should swap that into my 85 or if I should leave the 200-4r. I know that the overdrive trans is better for cruising, but I had 3.90s and a 26" tire with the TH350C and didn't mind having no OD at all (didn't really go over 55 on any highway!) I'm shooting to have around 400hp to the tire (had 320 with the stock ZZ4 heads and baby cam) and I'm pretty sure the stock 200-4r cannot hold up to that.

Here's what I'm really asking - should I keep the 200-4r (and therefore I assume have to have it built and put a new converter in it - any ideas on cost??) or just swap in the TH350C?

Thanks in advance!

I am going to start with: This is not a thread Hi Jack but a safety bulletin- replace or update the frame..
the Red 80 is before the car on stands and frame is the 86 LS T-Top MC.

1. transmission - 2004R up to 450 HP if built properly
2. TH350 standard transmission up 300-400 Hp no more
3. I see nothing about the Frame Suspension or anything else - speaking from personal experience - putting anything over stock HP in these G Bodies is a recipe for disaster. Torque to rear wheels causes rear end to load on driver side lifting left side and then the rear axle YAW and you have rear wheel steering when not expected,
Repair or replace the FRAME before any HP modifications - going 70 MPH backwards down highway is no picnic...
1. pull frame
2. media blast
3. Box in the Frame
4. put I beam or box cross braces with reliefs for dual exhaust
5. Reinforce the control arms
6. 3/16 steel cross straps in front of shock towers
7. Reinforce the upper control arms with 3/16 steel triangular bosses
8. connect the rear frame rails with a Class III trailer hitch
9. Get a custom rear end from SPOHN Currie or Quick Performance - make it wider than stock with stock mounting points for added stability.
10. then regardless of HP your assured a steady, well handling vehicle without wonky frame torque steering.
11. re-coat - powder coat, Reustoleum black industrial paint or POR 15 then rust coat the insides. I used the Industrial paint and there is no difference from powder coat and cost $50. still looks like new underneath I also rubber undercoat the underside after rust proofing.
12. 4.3 V6 fuel tank from RockAuto and an LS suited pump in tank.
The cross bracing is after these pics- I have a Currie 9 inch with Torino large bearing and all wheel disc brakes
Hope this gives you some ideas since your rebuilding the car anyway...

 

[doood]

I am going to start with: This is not a thread Hi Jack but a safety bulletin- replace or update the frame..
the Red 80 is before the car on stands and frame is the 86 LS T-Top MC.

1. transmission - 2004R up to 450 HP if built properly
2. TH350 standard transmission up 300-400 Hp no more
3. I see nothing about the Frame Suspension or anything else - speaking from personal experience - putting anything over stock HP in these G Bodies is a recipe for disaster. Torque to rear wheels causes rear end to load on driver side lifting left side and then the rear axle YAW and you have rear wheel steering when not expected,
Repair or replace the FRAME before any HP modifications - going 70 MPH backwards down highway is no picnic...
1. pull frame
2. media blast
3. Box in the Frame
4. put I beam or box cross braces with reliefs for dual exhaust
5. Reinforce the control arms
6. 3/16 steel cross straps in front of shock towers
7. Reinforce the upper control arms with 3/16 steel triangular bosses
8. connect the rear frame rails with a Class III trailer hitch
9. Get a custom rear end from SPOHN Currie or Quick Performance - make it wider than stock with stock mounting points for added stability.
10. then regardless of HP your assured a steady, well handling vehicle without wonky frame torque steering.
11. re-coat - powder coat, Reustoleum black industrial paint or POR 15 then rust coat the insides. I used the Industrial paint and there is no difference from powder coat and cost $50. still looks like new underneath I also rubber undercoat the underside after rust proofing.
12. 4.3 V6 fuel tank from RockAuto and an LS suited pump in tank.
The cross bracing is after these pics- I have a Currie 9 inch with Torino large bearing and all wheel disc brakes
Hope this gives you some ideas since your rebuilding the car anyway...


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Scary. Good tip on the hitch. Seems you can still get a class2 hitch through uhaul for $175. What were you doing that you wound up backwards at 70 MPH on the highway? My low mileage '84 with 300 hp LM7 behaves very nicely at 80MPH on v6 car springs.

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