Blowup rhymes with:
backup, breakup, buildup, burnup, buttercup, canup, checkup, cleanup, close-up, coverup, crudup, eggcup, followup, greenup, grownup, hangup, holdup, hookup, jessup, letup, lineup, linkup, lockup, makeup, markup, northup, pickup, pileup, printup, push-up, pushup, roundup, runup, setup, shakeup, speedup, stalcup, stallcup, standup, start-up, startup, teacup, tuneup, wakeup, walkup, warmup, windup, wisecup
Blowup sounds like:
bailby, bailiff, balbi, balbo, balboa, balfe, bayliff, behalf, belief, believe, beliveau, bellavia, bellboy, bellevue, bellhop, belliveau, beloff, belov, belove, belva, belvia, beowulf, bielby, bilbao, bilbo, bilby, billup, bivalve, bleep, blip, blob, blobby, blowpipe, bluff, bolf, bolivia, bowlby, bulb, bulova