Ford Mustang Forums banner
1 - 20 of 23 Posts

· Registered
Joined
·
14 Posts
Discussion Starter · #1 · (Edited)
Hey all,

Well, after 3 years and 3 different shops, the beast is laying down some nice times at the track. My son and I started this project originally as drift car, but he changed direction about midway through. What’s a suspension change, right? I really only have 1 question though. Are 3.73’s too high of a gear for acceleration at the Drag Strip? He’s laying down great times! But the MPH is lower than expected, like it’s falling off in 3rd towards the end of the track. Was thinking about dropping down to 3.55’s???

Mods: 4v B Head Teksid , IMRC delete, 1998 Cobra Intake / CAI / 100 Shot NO2 / 3800 Stall Converter / Long Tube Headers / Off road X Pipe exhaust / Tubular Rear Control Arms & 3.73 Gears / Dyno’d @ 298 HP NA with a 100 NO2 Shot on top of that. M/T ET Street SS and 3600 lbs with Driver

Best Time: 1.6 60’ 11.846 @ 112.81
Sky Building Plant Asphalt Tree
 

· Registered
Joined
·
14,541 Posts
Most people will run 4:11's or more with those engines. I'll let those with experience with those motors give advice, though.

Cool project, though.
 

· Registered
Joined
·
14 Posts
Discussion Starter · #3 · (Edited)
Most people will run 4:11's or more with those engines. I'll let those with experience with those motors give advice, though.

Cool project, though.
Originally that was the plan. But when we decided to throw a 100 shot of nitrous on it, we stayed with the 3.73’s because of the power adder and the torque value. I’m old-school so I always try to follow the logic that torque loves numerically small gears. So I’m a little lost on where I should go from here. 🤷🏽‍♂️
 

· USAF retired
Joined
·
10,266 Posts
I'd go 4.30s at least, maybe higher, depends what you're comfortable running it up to.
26" tire I presume?
 

· Registered
Joined
·
14 Posts
Discussion Starter · #8 · (Edited)
I'd go 4.30s at least, maybe higher, depends what you're comfortable running it up to.
26" tire I presume?
28” 10.5 on 15” rim.
No issues with a gear that high on NO2? Just making sure before I go buy a 4.20 or 4.30 gear. Have a spare Diff to build so no down time. Also want to have different gear sets so we can swap differential at track if need be. Don’t want to go higher than 6400 in 3rd gear. Shift points are at 6500
 

· Registered
Joined
·
14 Posts
Discussion Starter · #13 ·
Are you running Cobra cams or the Mark VIII cams?

You definitely want the 4.10's, 4.30 with the 28" tire

Post your dyno chart if you have it
Let me get my son to dig it out of the file cabinet. If I remember correctly, it was 298 HP @ 5600-5800ish and 307 Pound Feet. We’re taking it back to get tuned again with NO2 on the Dyno. I’m confident in our tuners emailed tune for the NO2. But would rather spend the money and get it done on the dyno with spray for best tune possible 🤷🏽‍♂️ We have set a hardline Flywheel limit of 450 HP on this stock motor. Already have donor motor from another Mark VIII for full forged build.
 

· Registered
Joined
·
14 Posts
Discussion Starter · #16 ·
if you can't find the gear maybe try a set of 26" in the rear.
Yeah, RockAuto had some 4.20 in inventory but sold out last year. Best I can find is that the 4.20 gears were a NASCAR set / cut. We’re probably going to go with 4.09’s. Would love to use use 4.20’s or 4.30’s, but the track is 1.5 hrs away, so don’t know if my son will go for that. Either way, running the math, an increase from 3.73 to 4.09 should yield a noticiable decrease in ET and increase in MPH which is what we’re tying to do. He ran consistent 11.9??’s last night, so the gear change will be happening soon
 

· USAF retired
Joined
·
10,266 Posts
Yeah, RockAuto had some 4.20 in inventory but sold out last year. Best I can find is that the 4.20 gears were a NASCAR set / cut. We’re probably going to go with 4.09’s. Would love to use use 4.20’s or 4.30’s, but the track is 1.5 hrs away, so don’t know if my son will go for that. Either way, running the math, an increase from 3.73 to 4.09 should yield a noticiable decrease in ET and increase in MPH which is what we’re tying to do. He ran consistent 11.9??’s last night, so the gear change will be happening soon
I run a 4.56 on a 26" tire at the track, 1/8th mile, and on the street I run a 275/60-15 tire, track is 2 hours away.
 

· Registered
Joined
·
426 Posts
The 11.8 @ 112 was with 100 N2O?
 
1 - 20 of 23 Posts
Top