I'm getting the 200 4 R from Monster Transmissions. I'm paying the extra $300 on their "heavy duty" to have it built to 500+ tq. (Standard build is 400tq, but my engine may come out a little stronger... I push her a bit hard so I figure it may bring some extra longevity)
2800RPM at 70 with 3.55? That actually sounds a little high to me... I was planning on going 3.73 with the 200 R 4. I did math based upon my current setup and future gear ratio. I'm not sure if it is all straight line math or not...but assuming it is...
My THM400 3rd gear 1.0:1 w/3.08 hits 3000 @ 75mph. I made a formula that basically told me a 200 4 R OD .067:1 w/3.73 would be 2434rpm @ 75mph. (Figured a 3.55 to be 2316rpm @ 75)
I wonder if I made some incorrect assumptions..!
Do I need the GM cable from the conversion page on the shift works website?
Thanks for the info!
1968 Firebird 400 Convertible Original: Engine, Intake manifold, Heads, Body, Stereo, 3.08. THM400. Engine rebuilt by Ken Keefer early 2012. New: Holley 4bbl 670 HP, hidden iPod setup, RobbMC mini starter, A/C, front disc brakes
