Hi everyone. I'm in the process of finishing the rebuild of a 350 to swap with the 305 that came stock in my 83 Trans Am. It currently has a 700R4 that shifts fine but could probably use some freshening seeing as it has about 90,000 miles and was probably not very well taken care of before I got it.

With the current engine I have a CC carb and distributor and will be using a non-CC carb and vaccuum advance distributor with the 350. I plan to use the car as a daily driver with some attitude and most likely keep the A/C with it as well (not that the a/c effects the trans decision, but...) I drive about 20 miles to and from work every day and make trips of 100 miles or more every couple weeks.

The question is "What would you suggest?" Keep the 700R-4 (has the O.D.)? What mods are needed for the non-cc carb and how involved? Clean it up? Rebuild it? Have it rebuilt?
Or switch to a TH-350? Getting a good one will cost how much more compared to everything involved with the 700r-4? Any mods needed for the TH-350 to be a good choice?

Please let me know your thoughts. I really need to make sure I'm not sucking gas too bad on my highway trips (gears in the rear are very conservative now) but initial cost and work is a factor too.

Thank you in advance for helping me out.

You need to wire a way for the lockup to work in the 700-R4.
Some people do this using the 4th gear pressure switch.
I'd stab myself if I had to go without OD based on the mileage you drive.
The non-CCC carb may have the right hookup for the TV cable already.
Changing fluid / filter and seeing how it does (you may want to adjust the TV cable a little bit to make sure the trans. is shifting correctly) would be what I'd do w/ the 700.
Good luck on your swap.

I'd stick with the 700R4. But I WOULD NOT change the fluid yet. I'd get the swap done, and see if it holds first.

When I swapped to a 350 from 305, my tranny slipped bad. Behind the 305 you couldn't tell any slipping at all, but the 350 was a whole new monster, and could feel the slip immediately - but mine had double your mileage.

So that's why I say try it first and see. If it holds up fine, then maybe swap fluids and change filter (great time for a shift kit as well). Otherwise, might be wasting your time/fluid/filter if it needs a rebuild anyway (like mine did).

Afterwards, do a complete fluid flush every 60k miles.

Also - tranny fluid builds 'gunk' from clutches/plates - these act as a friction additive. If not changed regularly, and then changed late - sometimes the lack of this 'gunk' can make an otherwise great tranny start slipping (since you lost the 'gunk' when changing the fluid). 90,000 isn't too far off base (depending on how it was driven), so you might be OK changing fluids/filter without ill effect. But I'd still do the swap first before I spent time/money on the tranny and see what happens (in case it needs a rebuild like mine did).

So far I like what I'm hearing cuz it kind of goes with what I already thought. My friend was insisting on a th350 and I really thought I drove way to much to not have OD.

question now is primarily regarding the lockup. I think I've seen kits for about $150 -$200. What are some pitfalls to avoid? Is there a "better" kit than others? Can I do this WITHOUT draining the fluid as suggested? What happens if I don't do this? I could be wrong, but is Cameron suggesting hooking it up without the lockup somehow? Is that possible? I'm not sure how that all works yet.
Thanks

(I've heard the same thing about trannys needing the gunk in the old fluid to help them work better). The fluid looks really fresh on the dipstick and it shifts really firm (with the 305 for what it's worth) so maybe it was maintenanced properly but when I got the car ALL the vaccuum lines were rotted and my 2nd oil change after 100 miles came out BLACK so I was getting a bad impression about the maintenance of the vehicle.

I use the TCI lockup kit - not sure of the price these days. It works well, but you have to remove the pan (ie change tranny fluid) to install. All of them except one requires the pan to be removed - the 'one' is a B&M kit that relies on speedo info and a preset speed (that you program). Haven't heard much about it though, but I've seen several folks here using it.

Only drawback to the TCI kit is the crappy little vacuum switch they include - it breaks very easily. I don't use any vacuum switch with mine, I just use the internal components connected to a manual switch (my cruise control switch) and I simply turn it on when I reach a sustained 50+ mph. This has worked really well for me for 3+ years. Folks worry about forgettig to turn it off - the car reminds you as it'll buck a bit below 40mph with it on - I've never had an issue with doing it manually. I did 'forget' on purpose 1 time just to see what would happen - basically it bucked a tad upon slowing until I got to a complete stop, and it just idled but at a slightly lower rpm - didn't seem to bother anything but I wouldn't make it a habit.

Again, I'd get it up and running, and see how the tranny does before I worried about the TC lockup - it helps gas mileage, and helps keep the tranny cooler at highway speeds, but it's not a necessity (at least to get going with).

There's a sticky at the top of the carb forum titled TCC Lockup - it has alot of good info. You might be able to rig your own manual switch from that info - some trannies can and some can't (depends on te year of tranny and the switch already factory installed. There's also a method using the ALDL connector I think - never really looked into that before.

More than anything, you'll want to make sure you get a good strong throttle cable bracket, and the right TV cable geometry corrector for your carb - the TV cable is critical, not just having it connected and adjusted but also having the geometry correct - if it pulls the wrong way (ie bad geometry of cable to carb), then it's pulling too hard or not hard enough, and thus it's not adjusted correctly even when the adjustment procedure is followed.

Hope that makes sense.

If you don't have a way to lockup your torq converter after a drive or two your trans will be destroyed

Not true at all. You trans runs alot without the TC locked - in stock form any speed below 35mph and all speeds when in 1st or 2nd gear. And there are alot of folks here not locking their TC at all with no issues after years of doing so.

A locking TC just improves mileage, and has an added benefit of reducing trans temps slightly, but in no way is it a required thing. If it was, GM would have built in a SES code for a non-locking TC (which they did not).

Thanks Cameron for all the info. That is very helpful. The carb is a holley 650 cfm. I don't have the model in front of me but where would be the best place to get the info regarding the correct geometry for the TV cable? Or should I just post the question when I get that far later?

I've heard somewhere before that not using the lockup will hurt the trans and I'm curious why people believe that. Did something else not get done correctly to lead to a problem they thought was caused by not locking up the TC?

Thanks again for all the helpful info

Here's your geometry corrector - attaches to linkage on your Holley to set TV cable geometry at correct place/angle...

http://www.summitracing.com/parts/SUM-700202/

Awesome! I'll order it today...A Christmas present to me!

Thanks