72 Dart Swinger 3.6L Pentastar +T5

myduster360 said
I was curious to see how the 3.6L Torque and Hp curves compared to common 340/360. I couldn't find a decent factory dyno curve of an old combo but the factory used a different SAE test standard back then anyway, so I replotted a 1999 5.9l Magnum.

Stock for Stock, the Pentastar loses out between 1500-4000rpm but kicks in after 4k and pulls hard to its peak Hp at ~6500rpm.
At 5000rpm, the little 3.6L is up a whopping 150ft-lb and 20hp over the 360!
By 6000rpm the Pentastar hits its peak Hp but the 360 went home early.

4.56 rear end should help out the low speed torque and keep the revs in the power band, while the .63 over drive will turn those rear gears into a cruise friendly 2.87,,,

View attachment 1714982787

I was measuring up gears on a spreadsheet I made as well. With the TKO I'd be coming out of 1st at 35.7 MPH@6500 RPM's, which is pretty tight and probably perfect for Autocross. However, at 65 mph in OD (.68) I'd be running 2463 RPM's. Not terrible but in my Charger now I'm pushing a 4000 lb car at 65 MPH around 2000 RPM's. I'll probably be driving it on the highway far more often than racing it but I was thinking I may shoot for something more in the range of a 3.91 instead. Have you any concerns of the 4.56's heating up while driving normally?