Strange one guys. Took my 89 Bird (Tbi 305) on the highway for the first time. I have 4.10s and a 700R4 with an unknown stall aftermarket TQ converter. Also stock diameter 245/50R16s.

At 60mph I'm at 2350rpm in OD.

Isn't this a bit high, even for 4.10s??? Does a high stall converter affect the RPM range?

 

No, that sounds about right for a .7 4th gear, with a 26" tire and 4.10 gears. Even 3.73s that get recommended frequently are pushing it with the 700R4. 4.10s you're pretty much trading highway cruising for drag strip performance.

 

4.11's are very steep, not a very friendly automatic ratio for daily drivers with any automatic transmission

Even with 3.5's I am complaining about highway RPM and wanting 3.23's

I remember the factory 305TBI had 2.73's behind it's 700R4 and would drop to 1400rpm at 46mph or something

 

Thank you guys I appreciate the info.

BTW, is there anything I can do to test what the stall speed is on my torque converter?

 

What rpm does the car start to move ?

 

I'm sorry you mean at idle? I just put in drive and it moves, idles at 750.

 

Sounds like you have a stock converter

 

Ok thanks. I was asking because the converter is blue and the PO replaced many components (rear gears, diff cover, intake manifold, headers and full exhaust, shift kit) so I thought he might have replaced the tq conv as well. He's long gone by the way, so I couldn't ask him.