The hot rod was crumpled underneath.
The man, whose name will not be released until police have notified next of kin, was a member of the Sulphur City Rod and Custom Club.
It is thought he was out preparing his car for a run with the Bay Rodders Tauranga this weekend.
President Dean Anderson said the man had lived in the Te Puke and Paengaroa area for many years and had a large local family, including grandchildren.
Mr Anderson said the man was probably getting his car ready for the two or three hot rod runs scheduled for this weekend.
The news was devastating.
"It's quite hard because the hot rod community is pretty close-knit.
"We do a lot of runs together. We don't see each other every day but we do runs all the time and everyone is among like-minded people.
"Having this happen is a big shock."
Mr Anderson said hot rods were among the safest vehicles on the road and their drivers took great care to look after them.
"Most people have them and they are their babies," Mr Anderson said.
"Our cars have to be certified as safe cars.
"It's very unusual for something like this to happen.
"Even the ones that don't look like they should be on the road, they are very safe and have to be because they are inspected so often."
The Pukehina volunteer fire brigade was first on the scene, which fire chief Errol Watts described as "disastrous".
"The vehicle was pretty much right under the truck.
"It was pretty crushed. The truck driver was trapped in the truck."
Mr Watts said the hot rod was "completely unrecognisable".
It took Pukehina and Maketu firefighters about an hour before they were able to free the truck driver.
"The front of the truck had been crushed in against his legs," Mr Watts said.
"He was very good. Obviously in quite a bit of pain but didn't flinch."
The 37-year-old man was flown by Rotorua-based BayTrust Rescue Helicopter to Tauranga Hospital with severe lower leg injuries.
A 28-year-old Tauranga man who was a front seat passenger in the truck was taken to Tauranga Hospital with an injured foot.
Diversions were put in place along Pongakawa School Rd and Maniatutu Rd.
