Quote Originally Posted by 82rangie View Post
What is he asking for the 3.9? Send me a pm, my 3.5 at the moment I think I may have sorted it has been freshly rebuilt all new bearings and full top end but no performance mods like cam or anything all just stock parts has a 350 Holley that was gIving me troubles but got it sorted now, you reckon I should just beef up the 3.5?? Considering it has all new gear in it
Your 3.5 can have the cam replaced and possibly even hi comp pistons fitted without even removing the engine from the vehicle. The 3.9 is worth about 10% extra torque but the 3.5 modded will produce same power or better at the higher end of the rev range. And it will last longer.

Also if your power is down have the distributor mechanical advance checked/recurved and run the idle timing at 6 to 10 degrees BTDC.