Help on drive shaft length

So I'm needing a drive shaft for a 67 barracuda and what the length is for it I have a 8 3/4 rear end with a 489 case large yoke and a 727 small block transmission. Also need to Know if I find a stock one in good condition what kind of horse power and torque can it safely handle. If anyone has a similar set up let me know what you went with. Its going to be behind a 340 punched out 30 over with a 4 inch stroker kit hydraulic roller cam kit with Edelbrock performer rpm aluminum heads with roller rockers a Edelbrock performer rpm airgap intake and a 750 Holley double pumper carb. If you have any useful advice it's much appreciated if you have a negative opinion please keep it to yourself thanks in advance