Rear Diff, Posi/open/spool?

[Racing6]

Which Carrier is best to run? Car is 184'' FED Carberated Small Block with Powerglide. Have heard a lot of different opinions can you give me more and maybe a reason 

[AF150]

Run a spool. You are not going around corners or smoking the tires to launch so no need for
diff or posi.

[masracingtd1167]

Please put a spool in it . Back in the day we ran open rears and they are dangerous ! Broken spider gears and the pins that go through them are what will hurt you if you break a rear . I have seen a few guy's put them in there cars and it really scares me . Use a spool and don't put too big of a tire on it . An FED need's a lot of wheel speed to go fast . Be safe and have fun.   

[George]

Spool.

[Racing6]

When we got our Slingshot it has an open rear diff, and I don't like the way it leaves, But thought there must be a reason

[wideopen231]

Reason it had open spool someone did not know  that dragsters need a spool. Nothing to break,lighter and 100% equal power to tires. No reason to run anything else.

[Cajuninjector]

Aluminum spool

[Dolmetsch]

Reason for open spools. Back when I started racing the rule book said `:no locked rear ends permited.
reason was that first there were no spools . Welding the spiders was common for those who wanted to try it. That is usually successful only for a run or two that you have a damaged rear full of crap spinning you know where. Ansen came up with square spider gear which was the first serious attemp to safely lock a rear. (still have the old catalog from back in the day) The powers that be still didnt want locked rear ends because if an axle broke it meant an immediate turn in a light car like a dragster or altered and instant accident. A posi was a reasonable alternative and I run one myself still. Then when spools came along came hi strength axles. Back in the day we had no such options but hunted around for a machine shop that would repline the axles for us. Once the axles became bullet proof it was safe to run spools and they became available. Many of the old popular diffs dont have spools available like 57 Olds for instance which can be had in some cases with new fine spline axles but is not available with a OEM style coarse spline. Spools are now not particilarly expensive. 8.75 mopar is a good rear end. 9 inch Ford if you are so inclined(Im not) BTW Early chevies rear ends were used back in the day although not much anymore. In fact I remember Cha Cha Muldowney breaking one in her small block chevy rail at Mohawk Dragway back when she was just another pretty face.
Don
I supplied the power for the What a Ride dragster back in the 90s. despite being a Shwindohl RED it had an open diff. It was a chromed 57 Olds diff and had Mark Williams Coarse splined axles. or so the label says. Despite the open diff it would run easily in the 8s with a flat tappet BB Chev. I am sure it would have gone quicker with a spool but despite that it was the first bracket car at our local track to turn in the 8s. We tried to buy a spool but would have had to replace  carrier and axles because there was no spool for the old style splines available.  Flat out couldnt afford it as the owner was like many of us a budget racer. So while not a great idea it is at least possible.

[Racing6]

Got a Spool coming, Thank You for the information