Cam and Stall Convertor
A torque converter will stall based on the torque it see from the engine..a 318 does not generate alot of torque, a 3000k converter behind a 318 will hard pressed to flash to 2400-2500 rpm.....
you stock converter probably flashes around 2000 rpm....you are not going to see a lot of gain for your money spend...
as said several times buy a GOOD Converter...it is night and day in launching a car.... many ions ago...i replaced a 10 tci converter which flashed at best to 3000 rpm behind a 340...and bought a Turbo Action 8 inch..that flashed to 4700 rpm....picked up 6 tenths...
In fact that converter I bought back in the early 80s is still in use in my 71 Demon...flashes to about 4800 behind a 360 these days..last time out went 1.502 to 1.514....60 ft time..
but hey..it is only money...nothing like buying the parts twice...