Can anyone tell me why in 4th gear my truck tops out at 2900 RPMs? It hits 2900RPMs and 80 on the speedo and that is it nothing more. It is a 4 speed manual transmission with a 5L(305) Chevy Small Block. It has a good amount of power in first, second, and third and also hits well over 5000 rpms in those gears but in 4th it just stops at 2900. It is a 1984 with no computer so I don't see how it would have a speed limiter. Anyone have ideas?