I changed my 2TGEU to 40mm dellortos, all I needed to do was unplug all the electrics going to the computer and bolt on the carbs, remember these engines were originaly designed for carbs so all the efi stuff is just added. The carbs should be running at about 3psi which is a lot lower than the EFI pump which would probly be at around 30-40psi. A regulator may be putting too much pressure on the efi pump and fuel lines so you might have to try bypass the efi pump and run a low pressure electric pump. I didnt have a efi pump as the car i was putting it in was originaly carbed. I just connected my electric pump to the 12v output from the on switch on the ignition so it turns on with the key. Once you hear the music the carbs put out, you won't want to go back.