Paul Starks said he felt "sick to his stomach" when he discovered a wall and railings had toppled onto his two sports cars in Dunfermline.
A drain had become blocked by debris, leading water to spill over, causing the wall in Coal Road to collapse.
Fife Council said it was disappointed and frustrated at the flooding.
More than Â£30m has been spent on the town's flood prevention project - 10 times the original estimate.
Mr Starks said: "My friend came through to me at about 04:15 and said there had been a large bang outside.
"I looked out and noticed the railings had come down around the cars.
"I came out and looked and realised the cars were badly damaged. Water was spewing out of the wall and I thought, not again.
"This is the second time it has flooded.
"I love my cars, it's devastating. It makes you feel sick inside and angry."
Pat Callaghan, Fife Council's executive spokeswoman for environment and transport said: "We're disappointed and very frustrated by the flash flooding event at Pittencrieff Park as, of course, nearby residents will be too.
"In addition to the planned weekly Friday check and clearance of the culvert grill, once we received the severe weather warning, we again checked and cleared the culvert trash screen at the bottom of the park on Saturday as well.
"Unfortunately the exceptionally heavy rain carried such an immense volume of debris down the burn from the park that it choked the trash screen to both culverts during Saturday night.
"The burn overtopped, the water was trapped within the park and eventually caused a section of wall to collapse at Coal Road.
"The flooding was reported to us at 4am on Sunday and an emergency response team immediately went out and cleared the blockage in very difficult circumstances.
"Fortunately the flooding didn't affect any properties, but two cars parked on the footway were damaged and the road was closed to allow the clear up operation."
The road has now re-opened.
Two cars were damaged when a troubled flood prevention scheme in Fife was hit by more problems during the weekend's heavy rain.