Topping out at about 90mph

[1 Wild R/T]

Spicer shows 3300 RPM's will get you about 70 MPH...

https://spicerparts.com/calculators/transmission-ratio-rpm-calculator

 

[Orange71SE]

Stuck in 2nd or your converter is f'd..

Tranny is new and converter was just put in this week. Changed it from a 3k stall converter. I can feel all 3 gears kick in.

 

[Orange71SE]

Did you buy the converter brand new? How old is the tranny?

Tranny has about 1k miles, converter is brand new

 

[davek]

with the 3k stall was it the same

Tranny is new and converter was just put in this week. Changed it from a 3k stall converter. I can feel all 3 gears kick in.

 

[Orange71SE]

with the 3k stall was it the same

Yes, been the same since i put the drive train in

 

[davek]

Yes, been the same since i put the drive train in

no I mean the rpm the same with the gears and speed and tires?

 

[Orange71SE]

no I mean the rpm the same with the gears and speed and tires?

Yes top end speed has been the same with both converters. Have not tried swapping to taller tires yet. I figured id ask here and see if someone had any other ideas as to why I'm leaving so much on the table.

 

[MoparLeo]

The tire/rpm/gear ratio formulas are straight forward. What else were You thinking/hoping it could be ?

 

[moparedtn]

A 275/60/15 tire is 28" tall. Just sayin'.

 

[Orange71SE]

A 275/60/15 tire is 28" tall. Just sayin'.

Yeah im running a 275/50/15

 

[Orange71SE]

The tire/rpm/gear ratio formulas are straight forward. What else were You thinking/hoping it could be ?

So seems normal to you?

 

[moparedtn]

Yeah im running a 275/50/15

Then you have about a 26" tall tire (25.82").

 

[Orange71SE]

Then you have about a 26" tall tire (25.82").

Yes, when measured with the weight of the car at 20psi (thats what i run them at for traction) its a tad bit under 25in

 

[MarPar]

 

[Orange71SE]

View attachment 1031617

Same here, maybe i should start off with a tire swap

 

[Hemirunner]

Do you actually have a tach or are you going by a calibrated ear? < sarcasm. Hopefully you have a tach. I had a 440 that wouldn’t rev higher than 5500rpm. I switched from manifolds to headers and it’d go to 6300ish. You’re not running 2-1/2 exhaust with conventional mufflers or something crazy restrictive like that are ya?

 

[MarPar]

Same here, maybe i should start off with a tire swap

Maybe, but me thinks there is something else at play.

 

[Orange71SE]

Do you actually have a tach or are you going by a calibrated ear? < sarcasm. Hopefully you have a tach. I had a 440 that wouldn’t rev higher than 5500rpm. I switched from manifolds to headers and it’d go to 6300ish. You’re not running 2-1/2 exhaust with conventional mufflers or something crazy restrictive like that are ya?

Open headers at the moment, and i do have an aftermarket tach.

 

[MarPar]

Open headers at the moment, and i do have an aftermarket tach.

Could it be not enough back pressure? IDK spitballing here...

 

[Orange71SE]

Maybe, but me thinks there is something else at play.

Others ive talk to have said maybe trans is slipping, but im sure i would feel like its slipping. Especially when at higher rpms