340 TC

[dancinwulf]

Thank you all for the input. I recently purchased the motor from a guy who pulled it out
of a car he bought and was putting a big block into. He didn't know anything about the motor other than that it ran good it just wasn't enough for him. My car is a street car I drive in the summer as I live at 6000 ft elevation and we have way to much snow in the winter. I have a 318 in it now and don't really want to tear down the 340 to see what cam etc it might have but wanted to get a better TC than what I have to put in with it. My gears are 3.55s and my 727 was rebuilt when I put my duster together. So it is in good shape I have put about 7000 miles on it in the last three years but have always wanted to get a 340 to put back in it.

 

[transman]

Thank you all for the input. I recently purchased the motor from a guy who pulled it out
of a car he bought and was putting a big block into. He didn't know anything about the motor other than that it ran good it just wasn't enough for him. My car is a street car I drive in the summer as I live at 6000 ft elevation and we have way to much snow in the winter. I have a 318 in it now and don't really want to tear down the 340 to see what cam etc it might have but wanted to get a better TC than what I have to put in with it. My gears are 3.55s and my 727 was rebuilt when I put my duster together. So it is in good shape I have put about 7000 miles on it in the last three years but have always wanted to get a 340 to put back in it.

Others may disagree, but IMHO, a stock 340 converter is probably going to be your best bet. In other words, a 2200-2400 stall converter. While I didn't live at the time I owned the Duster at the 6000 foot level, like you, I live in a mountainous area, and the car crossed the Rocky Mountains more than once.

 

[AJ/FormS]

At least do a compression test.
Cylinder pressure at your elevation is very important, and
with 3.55s it is possible to have less performance with a big cammed 340 than with a properly built 318. Or at least you might be very disappointed. This is because a big cammed 340 with low-compression, may not come alive until AFTER 4500rpm/about 42mph in first gear. A stock teener could be making pretty good power and performance up to about that same rpm,and so the performance difference between the two, up to 42 mph COULD be pretty similar
The compression test may lead to a cam swap
Remember; you said the PO pulled it because it wasn't enough for him; it may be a poor combo. You would be very disappointed to find that out after the install.
The compression test will tell you a lot.

On an unknown engine I would also do a LeakDown test