1970 Pontiac Firebird need new Positraction & GearsMay 19, 2014 - Author: BartBarton
I have a 1970 Pontiac Firebird with the 455 engine and automatic transmission.
Question: The firebird needs positraction and a new change in gears from 2-56 to ? The firebird has the TH400 transmission, 8.2 10 bolt Pontiac rear end. need something with more pulling power and still comfortable to drive down the hi way. 3,08 or 3.36 ? had a TH350 in car but 455 with 60 over mild camshaft, ate them ! Went with 400 now lost some pull in 1st and 2nd gear. what to do and how much?
Answer: You can figure you RPM at whatever MPH you want to drive with this formula RPM = MPH X Gear Ratio X 336 then divide this by the tire diameter in inches.
Here are some options we recommend see if any of these will work for you:
- Eaton positraction you will need is part number PFEA19674-010 $526.27
- Motive 3.55 Gears PFMWBP882355 your cost is $262.85 there is also a Yukon 3.36 Gears available part number PFYG GMBOP-336 your cost for this gear kit is $294-55
- You will also need a bearing rebuilt order our part number PFR-10-82 your cost is $ 116.41 plus S&H. These are all high quality aftermarket parts.
If you have additional questions, to place order or need help give Lance a call at 800-444-0755 he can help you. Installation is available in our shop in Maple Grove MN, just give us a call to schedule.