New Joiner

[67-Coupe]

Hey ya'll - I've been looking around on the web and found you guys a while back. I'm starting some mods on my car and wanted to drop in to research rear gears. So after reading it all I'm looking for some thoughts.

My Car:
67 Coupe 351w, edelbrock performer heads, intake manifold, 650cfm holly dblpumper w/ mechanical secondaries, headman headers. Never had it dyno'd but guessing somewhere between 320 and 360 bhp. Not much more to do to the engine other than upgrade the ignition (I don't think)

Tires: 265 70 15s though I think I'll downsize a bit - too much rubbing on the wheelwell. Someday I'd like big rims and smaller tire...

Current mods underway:
New T5 with a 2.95 first gear and .64 OD
install Rear locker
upgrade rear gear
Caltracs traction bars
upgrading to new clutch cable instead of old linkage
install Powerboost brakes.

It's probably never going to see the track though I do drive aggressively and don't want to be shown up by any 4bangers with a turbo. You wouldn't believe how many yahoos in a new dodge ram with a hemi want to race me! Actually, you probably do!

It has a 8 in rear end and I'm trying to decide what rear gear to put in. I guess the question is how much do you lose in a 3.55 rear gear versus 3.73 or higer? I don't mean RPMs, I mean acceleration or performance. It's not a daily driver and I know I'll get all kinds of answers ranging from 3.55 to 4.3. I just need to figure out which is right and not regret what I put in. Same decision going with the 351 over the 302.

Thanks!

David

 

[mustangdave]

Have u upgraded to a hotter cam? If so, I would go 3:73 or maybe a little lower/ if cam is stock, 3:50 is fine. Definitley stay with the 351W; you jave a nice start there. Welcome!

 

[Rapid]

Hey ya'll - I've been looking around on the web and found you guys a while back. I'm starting some mods on my car and wanted to drop in to research rear gears. So after reading it all I'm looking for some thoughts.

My Car:
67 Coupe 351w, edelbrock performer heads, intake manifold, 650cfm holly dblpumper w/ mechanical secondaries, headman headers. Never had it dyno'd but guessing somewhere between 320 and 360 bhp. Not much more to do to the engine other than upgrade the ignition (I don't think)

Tires: 265 70 15s though I think I'll downsize a bit - too much rubbing on the wheelwell. Someday I'd like big rims and smaller tire...

Current mods underway:
New T5 with a 2.95 first gear and .64 OD
install Rear locker
upgrade rear gear
Caltracs traction bars
upgrading to new clutch cable instead of old linkage
install Powerboost brakes.

It's probably never going to see the track though I do drive aggressively and don't want to be shown up by any 4bangers with a turbo. You wouldn't believe how many yahoos in a new dodge ram with a hemi want to race me! Actually, you probably do!

It has a 8 in rear end and I'm trying to decide what rear gear to put in. I guess the question is how much do you lose in a 3.55 rear gear versus 3.73 or higer? I don't mean RPMs, I mean acceleration or performance. It's not a daily driver and I know I'll get all kinds of answers ranging from 3.55 to 4.3. I just need to figure out which is right and not regret what I put in. Same decision going with the 351 over the 302.

Thanks!

David

Welcome Back. I just finished a T5Z swap myself and had asked about gears. I have decided to go with 3.50s and a Tru Track limited slip. MIne is a daily driver and I want to keep it flexable. You will really appreciate the OD.

 

[67-Coupe]

Have u upgraded to a hotter cam? If so, I would go 3:73 or maybe a little lower/ if cam is stock, 3:50 is fine. Definitley stay with the 351W; you jave a nice start there. Welcome!

It does have a little bigger cam in it. Sadly, I don't remember the specifics, it was a few years ago.

 

[zookeeper]

351's have a ton of torque, so for the street you can get away with taller gears. I don't know how often you drive on the freeway, but a 3.73 with a T5 trans would make a good stoplight-to-stoplight setup without sarcificing too much on the freeway. I've used 3.89 gears with a 4 speed and I hated it. It was great in town, but miserable on the freeway, but that extra gear would really help you get the rpm's back down.

 

[68EFIvert]

I have a t5 and decided to go with 3.70 W/Trac Lock in my car. There are a few places on the net that you can plug in your specifications, tire size mine are about 26" tall), final drive ratio (tranny overdrive) and sample gear ratio and it will give you what RPM you will be cruising at highway speeds. I think it came at 2200 @ 60 -65 RPM with my setup (where the power band starts with my cam). I had to purchase a 21 tooth speedo gear to calibrate the speedo. Here is a link for a calculator. http://www.carforums.net/rearcalc.php