This is my first build and have gotten a great amount of advice on here. My 86 MCSS frame is away getting blasted and powder coated and i would like to have he rear end ready to put it all together asap. My engine will be a stroked 6.0 (eventually on boost) and very possibly a 4l80 (this is what my research is telling me is best fit). MY goal is to street and drag occasionally. I was looking at the ford 9" but not sure what gear ratio to go with. any help is much appreciated.
What gear ratios are you running?
- Thread starter johnnunez29
- Start date
- Status
gotta get measurements. im going to be running 20" for now. not sure what in the future. but not a huge fan of the big wheels. is that a decision i need to make first?
20 what? Come up with an actual tire size, not rim size.
If it has a stock cam, then you need to figure that in for determining cruise rpm and track max rpm. Or, what is the motor going to end up with even if you aren't going to do it at time of initial install.
And as Built6spdMCSS mentioned, any power adders?
That’s tough, at the beginner stages . Will be on boost hoping for around 1k hp. Need to speak with builder I guess to determine cam. Been a nightmare to get this going
Spicer Transmission Ratio RPM Calculator
Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio.
spicerparts.com
For overall tire size go -
Tire Sizes
Browse tires by size. Search hundreds of tire sizes to find the right tire size for your application.
tiresize.com
Last edited:
That's a dilemma. The gear that you need for the track at 400-500 hp will be off by a lot at 1000hp. So either plan to change them as needed or pick the gear for 1000hp because you're not going to pick one that will work for both.
Since you have an OD with the 80e plan to drag it, 3.73 at the lowest. Many 1000hp+ 8 second cars run 3.73's.
Best suggestion I have is go to Wallace racing calculator online, type in 3.73, 5% converter slip, 28" tire and 1-1 ratio for 3rd gear and it's like 148mph at 6750rpm or something. It's going to drive great on 3.73, 4.11, 4.30 or anything in there is a good choice also.
You might loose half a sec at the track with a 3.73 that's more 1000hp 8 second territory over a 4.56 that's more 375hp 13 second territory but if you know you're going to swap boost down the road, determine what your goal quarter mile time is, determine the trap speed, and do the math to find the gear.
Best suggestion I have is go to Wallace racing calculator online, type in 3.73, 5% converter slip, 28" tire and 1-1 ratio for 3rd gear and it's like 148mph at 6750rpm or something. It's going to drive great on 3.73, 4.11, 4.30 or anything in there is a good choice also.
You might loose half a sec at the track with a 3.73 that's more 1000hp 8 second territory over a 4.56 that's more 375hp 13 second territory but if you know you're going to swap boost down the road, determine what your goal quarter mile time is, determine the trap speed, and do the math to find the gear.
- Status
Similar threads
