Hello everyone. My question is are all 700r4's lock ups? I have a 85' Iroc with the 305 TPI and auto. I want to buy a 2200 - 2400 converter for it but dont know what to get. It has me a little confused. Any help would be great. Thanks.

 

Your 85 700R4 is a lockup TConv. You could do a non-lockup if needed. Is it stock? Carb or Injected? Still got the ECM?

 

If the car is street driven you would want to keep lockup and yes while all 700r4 trans are lockup all 700r4 aftermarket converters are not, I would keep lockup theres no disadvantage to having it and it saves alot of gas.

 

Yes the care is street driven. I plan on some other mods here real soon. The engine needs a rebuild so going with a mild cam and set of World Products 305 Toruqer heads for the 305. I think with that and edelbrock headers with a 2200 -2400 stall should be a nice daily driver. Thanks for the help.

 

Well I would suggest at least a 2800 9.5 inch stall 12 inch stalls are power eaters and heat generators. with the weight loss on the turning mass and the stall i think you would be amazed.

 

That sound like a lot of stall for driving to work everyday. I have to drive 30 miles one way. The cam is only like the second one up in the extrem energy line.

 

So in a larger stall, its best to do a smaller diameter? Interesting. I did not realize that. Not to steal a thread, but a 700R4 behind a 355/750DP/Perf RPM intake and cam .488-.510 + 1.6 rockers 234-244dur/WorldSportsman2/SLP 1 3/4 headers/the works/3.42s and may change to 3.73s one day, what would be my target stall range and TConv size? THX =)

 

I ran that set up in a 69' Nova I had. But I had the th350 trans. I used a 3000-3200 stall and loved it. I used same cam and intake. The heads I used were 69' 327 castings(441's) with home port and polish. Car was fast and very fun whipping up on some of my friends mustangs.

 

Not really at least not in our converters, 1 they are alow str which makes them very efficent in fact above stall speed we have has dyno test unlocked at 96 percent efficency. Plus with lockup the efficency become 100 percent at any RPM range once the converter locks so theres no effect on highway cruising speed economy.

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in you case I would say in the 3500 range, and yes large converters require exstreme fin angles to getthe higher stall enery that is not transfered to the wheels is heat and they make a alot. Smaller diameter converters require much less angle to acomplish the same goal so are more efficent not to mention the weight loss of around 12 pounds which may not seem like alot for the car but its considerable on a rotating mass of the drive train simply put your engine will turn up much faster.

 

Hmm. Thats good info to know and makes total sense. Thank you for explaing that =) I have a 3200RPM converter now. Its a tranny shop special and I think its a Daaco. Size looks like its std. Fills up the bellhousing =)

 

To run a 3500 stall would I have to change from my 3.23 rear gear to something higher? I also live down by New Orleans and drive the car up to Memphis. I didnt know that that high of stall would be ok for driving on the interstate like that.