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4.10’s, stock gearing in mine. My 1st gear was pointless in my 65e. Now I pull 1st to low 50’s and 2nd to mid 90’s for mph.
Good, cause I am swapping mine on the Twin Turbo 4x4 truck. The factory 3:42 Blows...
Maybe for a standing 1/2 mile or mile they would be good but in general they Blow !!!
So I used my daily driver tire data in the table (indicates 275/45R20 is 29.74", tire manufacturer states 29.0"...whatever)...I identified the "combo" in the upper left corner of the calculated data (i.e., 4L80 w/ stock gears & 3.42 rear, etc). First the transmission ratios:
To Pat's point, the advantage of the aftermarket 4L80 planetary set is more appreciable with the higher (lower numerically) 3.42 gears than the 4.10 gears. There is a calculated 7 mph speed reduction in 1st & 2nd gears with the 3.42 rearends and only a 5 mph reduction with a 4.10 ratio. But at this point, on paper at least, the "value" of the aftermarket planetary set appears to be marginal at best FOR EVERYDAY DRIVING. I'm very curious to see how it feels at the track to see how much RPM drop I have on the 1-2 and 2-3 shifts, although admittedly I won't have the benefit of a before/after comparison.
Go as big on the throttlebody and intake tube as you can. I ran a 105mm and 5” intake on mine.
I'd love to put a 102 mm on there but it would likely require quite a bit of fabrication to the MP122hh plenum (j-tube), and I believe that there may be a point of diminishing returns? Based on the plenum O.D., it "appears" that the I.D. is smaller than 102 mm...just went out to pull the TB to see if I could get some rough measurements and got hailed on, so maybe a little later--was also rewarded with losing the plastic clip that secures the trans kick down cable (any help on a replacement is appreciated). I would surmise that as long as the intake piping is larger than the plenum I.D., has minimal bends, and the TB is at least as large as the plenum I.D. I will have done the most that can be done short of spending excessive $$$ for extrude honing/porting of the plenum?
Edit: Found the retaining clip stuck behind the AC compressor bracket. Is that second cable attached to the TB shaft cam for cruise control?
Last edited by GoatChs; 02-15-2019 at 06:43 PM.
Reason: Cable Identification?
02-15-2019, 12:34 PM
4L60e-4L80e Gear Ratios / RPM / MPH Tables
