Matching Gear to Engine set-up

[ff6849]

What gear would work the best for my set-up:

3500 lb 73 Cuda
440 with 915 heads (mild head work, stock bottom end 10/9:1 compression)
TTI headers with 3' exhaust with  X pipe 
comp XE274H cam
Hughes Roller Rockers
800 AVS eddy
Holley Street Dominator intake
MSD igntion
275/60R/15 rear tire
A518 transmission (so I not worried about hwy drive-ability)

I am leaning toward 3.55 or 3.91. I don't think my set up requires anything lower like 4.10's. Car is mostly street driven may see the track one or twice a year. Do like driving it aggressively. From all the post I read too much gear can hurt performance just as not enough gear. I am not sure how to match gear ratio to my engine set-up. Looking for what will give best overall performance.       

[Aracer]

3.91 because 3.55 is like 3.23, slow off the line. And a lot quieter than 4.10

[erat340]

Here come all the commenters on how they Think you"re going to drive the car....... What RPM and speed are you going to spend all your time at?

[Chryco Psycho]

you have to know where the engine is happy rpm wise , then do the math so the engine is happy at the highway speeds you normally travel at with the tire size you are using etc , you need to work it all out , not hard but it takes time to work it all out

[erat340]

So the other 364 days of the year you"re not at the track, are ya realley gonna be happy hearin that motor scream with 391s/

[brads70]

I have 3:55 in mine with a 4L60 OD , it's the engine combo that will determine what gear it cruises at best. I should have went with 3:73 and the engine is not happy at 2000rpms at 60 MPH it likes 2300-2500 which is 75-80 MPH for me.  Feels almost like it's lugging at 2000 rpms
Hope that help! 
Brad

[Chryco Psycho]

So the other 364 days of the year you"re not at the track, are ya realley gonna be happy hearin that motor scream with 391s/

He has the 518 OD trans so 3.91 will be similar to 3.23 or lower numerically

[erat340]

That would work OK. Ive had my 833-4 rebuilt with a 309 1st and I run a 276 rear. Best of both worlds, whaddya yhink?

[ff6849]

with my A518 @ 75mph with 28' tall tire

3.55-2200 rpm's
3.73-2320 rpm's
3.91-2430 rpm's

[Aracer]

So the other 364 days of the year you"re not at the track, are ya realley gonna be happy hearin that motor scream with 391s/

YUP, I have another car to drive in traffic, so a slow hot rod is a Foogaysee, that gets left behind at the light. Hey, he asked didn't he?

[Oldschool]

Here is a handy reference chart for tire heights to help you figure out the ratio that you want:

http://www.jekylhyderacing.com/HeightofTires.htm

 

[Bullitt-]

try this to see your RPMs etc.  http://vexer.com/automotive-tools/speed-rpm-calculator

[Chryco Psycho]

I have the 833 OD with 3.09 1st gear & 276 , not bad off the line 3.23 would be better but the top end is amazing , idling at 75 mph in od