weird problem

[custom one]

i keep popping off vacum hoses off when driving my car.they pop off at the carb.what can be a cause of this.shouldnt it be sucking (vacuming)and not blow out.should i wire tie them on.i wonder if there vibrating off.any guesses out there.

[bad news]

hey bill sound to me like your getting some backfire what have you done to it lately changed the timing//??? could a plug wire got crossed?? a cracked dist cap??? a valve going bad ????something is send cumpressiom up thru the carb thy looking at the easiest frist pete

[custom one]

I dont think im backfireing,and everything you posted has been recently done.its poping of once in awhile (3 times this summer)so its not to often.plus im using aftermarket yellow vacum lines.(which might be the problem)my set up is

350 4(remanufactured ?????)you know i do got a block # i should post on here to try to find out some info on it.
ta intake
stock heads cam and internals
770 holley s/a
2inch spacer
stage 2 scoop
sealed carb box
proform hei distr.
accell u-grove spark plugs
msd super cond. wires.
i have timing set to most vacum 19-20 llbs from mainifold (have not done it with a light)