[Blaster]

I am building a 52 chevy pick-up and would like input for the trans/rearend selection and converter stall speed. My thoughts are 700r4 trans with 3.5 rearend gears(currently have th350/4;11. Here are some vitals that may apply:
1. 327 (mild) headers, dart heads, mild cam, 600 cfm carb.
2. Wheels 15 inch, don't know tire height yet.
3. Building a weekend driver, but will drive comfortbly on freeway trips....
Thanks for any input....Randy

 

[302 Z28]

Sounds like a good combination. Try and size your wheel diameter to get your 70mph rpm in the 1800 to 2200 range and should be perfect.

Vince

 

[macx]

Another Trans

You may want to also look at the
2004R - the gear spreads aren't
as extreme as on the 700R4 (you wouldn't have as big an rpm drop between 1st and 2nd, or 2nd and 3rd), and they can be built up about the same.

 

[packratwrecker]

If you run a 28" tire, (235-75r15, 255-70r15,etc) you should be right on your mark, with 3.50's, and the 700r4.

 

[M&M CUSTOM]

Building a weekend driver, but will drive comfortbly on freeway trips....

You may want to also look at the
2004R - the gear spreads aren't
as extreme as on the 700R4 (you wouldn't have as big an rpm drop between 1st and 2nd, or 2nd and 3rd), and they can be built up about the same.

For the application intended, I don't think he will mind the RPM drop, and I agree, they can both be built the same for the same price.

 

[macx]

RPM Calculator

Here's a handy link, use the one that
calculates mph at rpm/tire dia/ratio

http://www.smokemup.com/auto_math/index.php


The one place that might be noticeably
different is the 1-2 at street rpms.

with the 700R4 you'd go from 2500 to
1250 at 17mph or 3000 to 1500 at 21 mph, a fairly significant drop esp in a heavier vehicle.

with the 2004R, that would be 2500 to 1500 at 20mph or 3000 to 1700 at 23 mph. I guess it depends on how a person drives along with all the other variables such as ratio, vehicle weight, engine torque curve, etc.

 

[M&M CUSTOM]

Re: RPM Calculator

The one place that might be noticeably
different is the 1-2 at street rpms.

a fairly significant drop esp in a heavier vehicle.

I guess it depends on how a person drives along with all the other variables such as ratio, vehicle weight, engine torque curve, etc.

The TH-700R4 in my 1981 Malibu will set you back in the seat and chirp the tires with the 1-2 shift and a heavy right foot.

The TH-700R4 in my 1988 GMC Suburban operates in a fashion that the lower first gear helps get it's bulk moving, and operates like any other vehicle aside from the fact it will use more gas than most for the same task, making the stock 40 gallon gas tank a friend of mine.