1/4 time for 4.10s vs 3.55s

D

dsl4x4

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Jan 14, 2008
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Last time I ran my truck got 15.1 on stock transmission. Now have a built trans and lockup switch. If I change to 3.55s what kind of difference would I get?
 
31s and around 300 for right right now. Going up to about 500 in couple months.
 
3.54's without a doubt, 4.10's will not give you enough gear for the future.

Jim
 
i got 410's, and 600plus hp. besides being at 2200rpm when im at 70 or75, there fine. dont waste your money. but im not a diesel pro like jim.
 
If he's got the R's it won't matter...as long as he's making enough power at those R's.
 
i ran 12.43at 104 with my 4.10's and 1.67 60' time and then switched to 3.55's and larger injectors and now run 12.46@107 with 1.74 60' times.

Lavon
 
Deeper gears offer more mechanical advatage as long as you can make hp at where your turning it to. I have all to much fiqured this out with the stock camshaft, ive played with many diff. ratios in the ol 9" ford, diesels just have a flat narrow torq. band and can make gearing a challange. Find what works for you and do that! It has a ton to do with your tranny gearing, tire height, and hp/torq. Order you a Power Speed Calculator #89650, from summit or jegs thier cheap and have helped me tons with gearing decisions for many years. Ryan
 
LAmiller said:
i ran 12.43at 104 with my 4.10's and 1.67 60' time and then switched to 3.55's and larger injectors and now run 12.46@107 with 1.74 60' times.

Lavon
Click to expand...
:clap:

i love this! whack! actual true numbers for a response. i wish all threads had a reponse like this. great job LAmiller.:Cheer:
 
3.55s! Easy choice
These motors fall on their face at 3400rpms. CR is a different story.
I am going to 3.55s next year for sure. Currently 4.10s 12.39 @109mph is the best so far (30" tires, 2wd). RPMs don't matter if you aren't making power. I want my truck pulling toward or just hitting 3400 rpms by the time I cross the stripe. If you are doing 8th mile then go with 4.10s.
If r's matter that much, then on a run that I didn't go into overdrive and my tach was strait down (~4500) crossing the stripe why didn't I run the same time as with OD? I only went 99mph? That may be an exaguration but you get the point.
If you aren't sure go dyno your truck, look were it makes power, and go from there. You can learn how to cut good 60fts, a lot of that has to do with driving.
 
crewcab what kind of tires do you run while your racing? still running a 160 in that 94?
 
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