Gearing for the 1/8 mile vs the 1/4... What do you guys like to do?

What do you guys tend to do? I ran a 4.57 gear at US 60 race last year... I was getting into 3rd before the finish but there was lots of "head room" at the end of the run.... I was running the same gear at the 1/4 mile track and there was less "head room" in the rpm department but still enough room I feel to make a change as well... So what does a guy do? I have a set 4.71's but going from 4.57's to those I don't know if it's worth the effort... I think a 5.00/5.14 gear would be optimum for my current setup in the 1/4 mile but that seems like a awful steep gear... Seems like I would need a 5.67 gear to put the engine at peak rpm for the 1/8 mile but again the seems like a very steep gear for a 90 mph run... Truck has 30.4 dia tires a c-6 trans and I was calculating in 6% slippage for the converter... If anybody wants to double check my numbers for me but I think they are accurate....Decisions, decisions... All opinions/ experience welcome... Thanks

How high you turn it? Hell you already have more gear than me and I have 33" tires.

The big question is...How many times a year do you run 1/4 mile ??

I only turn it 6500-6700 rpm.... I only run 1/8 mile a handful of times a year.... My local track is 1/4... I'm not against changing gears once in awhile...  I have three aftermarket 3rd members now so I guess I just need to decide what ratio's I want to keep setup...  Also wondering if the gains are worth the effort and wear and tear on engine/trans. What kind of ET gains could I expect going from 4.57 to a 5.43? Assuming the truck will still be hooked up... And not run out of rpm.... Maybe I'm out of my mind putting that much gear in the truck but it looks like the math works out that way... Thanks again

You may not see much gain in et but it'll sure run hard.

With my 460 with 4.86 gears c6 and 4000 stall 31x10.5w I was turning 6200 at the 1/8 buy the 1000' mark I was in the rev limit it was set at 6600 rpm I know you run the fe engine but this might help you mine ran 6.72 at 99.5 mph in the 1/8

Realistically, you would like to gear it so you are just above your shift point at the finish line however, gearing it for the best starting line actions will be your best gearing ... hopefully you can get both to be the same.

6200-6300 rpm is about where the current combo makes peak hp... I usually shift 6500-6700 rpm... I really didn't want to do gear changes at US 60 but maybe that would be the best time to try a different ratio... What's the theory of being beyond peak hp rpm at the finish line? Kind of thought you would want to be at peak not past? thanks

The main purpose is to take full advantage of the extra wheel horsepower the gearing would give you on the gear changes but, if the starting line reaction gets uncontrollable then it certainly won't help.
Going from a 4.57/1 rear gear to a 5.43/1 rear gear will increase RPM about a bit less than 1,000 RPM at the finish line.

bluef100fe wrote:I only turn it 6500-6700 rpm.... I only run 1/8 mile a handful of times a year.... My local track is 1/4... I'm not against changing gears once in awhile...  I have three aftermarket 3rd members now so I guess I just need to decide what ratio's I want to keep setup...  Also wondering if the gains are worth the effort and wear and tear on engine/trans. What kind of ET gains could I expect going from 4.57 to a 5.43? Assuming the truck will still be hooked up... And not run out of rpm.... Maybe I'm out of my mind putting that much gear in the truck but it looks like the math works out that way... Thanks again

I don't think you'll incur more "wear and tear" by gearing the truck to run where it's happy. Keep in mind that too much gear can bring along some undesired launch symptoms. Gear it to launch consistently and trap just above peak. Your e.t.'s will be more predictable. Make the combo happy...you'll be happy.

That's a LOT of gear IMO. I gear for 1/4 and run both.

Damon,

Good to see ya back posting.... The little FE needs all the help it can get... Classic problem of a heavy vehicle (3850lbs) and small engine...  Converter goes to 4200-4300 on the Transbrake... 60 fts in the low 1.6's usually around home... Has dipped into the 1.5's at US60.... Just looking for a little more like usual... And it would be nice to get a little higher up in the power curve at the stripe and get into 3rd a little earlier when 1/8 mile racing... Thanks for the replies so far guys

If you see 1/8 mi. and 1/4 mi. tracks regularly, I'd set up 2 carriers for sure.

Torque = 1/4 mile gear   

Yes Damon a bigger engine would probably do the trick lol... I have a start on a stroker deal but I need to keep collecting parts as money allows

I still run the same 4.30 gear as when I was running a 428 (440ci) and then a 427 (458ci) however I wasn't turning them as hard.

Cody, are you building a FE stroker or a 385 series stroker?

I have a bunch of FE stuff to use up.... Bought a cheap 4.250 scat stroker deal a while back... Just haven't had time or money to piece it together and the 390 is holding it own for now... I just put up a garage on my property. I've only been living there for six years... So that is taking most of my play money... It's a shell with no doors for now but I hope to have it insulated and doors on it before winter... Anyway must be nice to have a light car with a decent size engine... I would love to get back down too a 4.10 or so gear for street driving...

Light car? My car is a pig compared to most   

3213# wet with driver.

I'm so glad to be back at my shop where I can actually work on stuff again. Been busy getting it back in shape along with other long overdue projects and maintenance.

Glad to hear it Damon... Keep on keeping on... I wish my truck weighed what your car does... It would almost be kinda fast then... I wonder how much ET there is in the 1/8 dropping 640 lbs. off the vehicle... I know the driver could stand to loose 40# of that lol