questions here????

[cstreu1026]

I seea couple hundred less RPM on the highway with the auto and 4.10's than I did with the stick that's why I think the 4.30's would be good with an auto. Of course without the PI swap if you take it the track its probably going to be wheezing pretty bad on the big end.

[Adam]

with 4.30s on a non pi 4r70w car,it would be dead at 1000' epecially if it still has the factory 6050rev limiter. NEVER EVER go into overdrive at WOT.

[cstreu1026]

now if he did the PI swap with some ported heads and some cams...

[Lee12609]

5th gear in the T45 is. 68, 4th gear in a 4r70 is .7, so the rear gear is the difference in cruising rpm.

I cruise 75+ 20+ miles a day, that's why I don't consider a steeper gear. You are talking 200 rpm difference at 70mph so its not bad, but for a daily driver not really worth the slightly better acceleration to me.

And with non pi stuff it would definitely fall over at 4800 rpm no matter what gear, so to make the most of the combo he needs to shift around 5200, but would still be in 3rd, and running mid 14s.

[penceracing]

cool thanks. am goin to do the p.i swap next year. am goin to pull the motor and tranny out when i paint it so and to the motor will be easiler to work on . after the swap i was goin to do the bigger tb and pletem, underdrives, longtubes, and maybe the cam upgrades also. i would like to put a 3500 to 4000 stall in it to. would it help out also to do some port work on the p.i heads??? I would love to supercharge the car in the future..

[penceracing]

the car at one time had long tubes stage 1 cams, dyno tuned and chipped with a programer. i have notice the rev. limiter is off i guess if i manuel shift it i can shift it at 6500 and if i dont it has went up to 7000 but i let off so i would damage anything lol... I have also notice to if i shut off the o/d and i get into it i have notice that it comes back on. Is there a reason for that???

[Lee12609]

sounds like my car and the horribly inaccurate factory tach. i've hit 6600rpm on the factory tach while datalogging and the motor really only revved to 5600rpm. infact stock shfit points are pretty much 4600 rpm, even on the stock tune my car according to the stock tach never shifted below 6000rpm.

i'm not sure what the stock rev limiter is but there is no need to rev a non pi motor any higher than 5500rpm, its out of breathe way before then anyways.

[penceracing]

yea i kind of figured it was out of its hp power range if i manuel shift it at 5500 it wont shift until 5800 or so.