Chevy Nova Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
162 Posts
Discussion Starter #1
My current set up is:

3400lb car
548 ci 750hp 700tq peak torque is at 4000
th400 trans
4400 stall
4:11 rear gear

Two things I am going to do is freshen the transmission and tighen up the converter to about 3200-3500.

I am trying to make it a little more street "friendly". My question is what gear should I run? 3.73 or go as high as 3.55??
 

·
Premium Member
Joined
·
9,228 Posts
Use one of the formulas to figure out exactly what RPM you will turn with your gear/tire combination. Only you know what you are comfortable with RPM wise as far as street cruising.
 

·
Registered
Joined
·
162 Posts
Discussion Starter #3
I would like to run the 3.55's but I don't want to kill the quarter mile times. Has anyone made that gear change and what did it do?
 

·
Premium Member
Joined
·
15,966 Posts
I have gone from 4.10 to 3.73 ET change was Nothing. Driving on the street was much better.

You should be much happier with a BBC. Your torque level is much better and can make use.

1/8 ET I gained 2 mph with the 3.73

I believe the 4.10 to 3.73 change has minimal ET change with greater advantage to street driving.

A 3.55 is better street, and less ET advantage.

With the CU you have, I would lean to the 3.55, should MPH very well.

IMHO
Al
 

·
Premium Member
Joined
·
9,228 Posts
A street/strip car is ALWAYS a compromise...you can't have the best of both as nice as it would be. We switched from 4.10 to 3.89 rear gear in our race car and actually went quicker & faster. Quicker is what you want for ET, less RPM for street driving. It was only 200 RPM difference between the two but that all depends on the diameter rear tires you are running. Map it all out on paper and it will probably become much clearer on where you want to go. Rear gears are cheap so it's an easy change if you don't like where you end up.
 

·
Registered
Joined
·
162 Posts
Discussion Starter #6
After some culculated thought, I'm going to try the 3.55 ratio. My tire height is only 28.5 and with the 4.11 I run out of gear way before the quarter mile. I did run a 6.77 in the eigth mile with alot of tire spin. With that said I think the 3.55's and lowering the stall speed will ease the tire stress and give me a lot more room on the big end. Thanks for your input guys. -Brian
 

·
Registered
Joined
·
34 Posts
He'll leave the gear and install a built 700r4... Or built 2004r... 30% lower first and second gear and with an over drive it will drive like a 3.20 series gear on the high way... Cruising 60 mph at about 1800rpm or so with a 29"'tire good luck
 

·
Registered
Joined
·
191 Posts
I run a 29" tall Hoosier with a 4.11 gear, I go through the lights at 8000 RPM @ 153+.

Don't put too tight of a converter in that thing, It will make it harder for the motor to accelerate.
 

·
Registered
Joined
·
162 Posts
Discussion Starter #9
I run a 29" tall Hoosier with a 4.11 gear, I go through the lights at 8000 RPM @ 153+.

Don't put too tight of a converter in that thing, It will make it harder for the motor to accelerate.
I'm all done at 6500 rpm.
 

·
Registered
Joined
·
191 Posts
I'm in the same boat, I want to go through the traps at a lower rpm as well.

I'm going to tighten up the converter so it flashes a little lower, makes less power, pulls the motor down a little more on the shift and in turn goes through the traps at a lower rpm.

Keep in mind, if you only change the rear gear to a numerically lower gear it will make the converter flash higher.

I suggest only one change at a time though.
 
1 - 11 of 11 Posts
Top