Based on the experiences from testing, it was quickly concluded that a more powerful and flexible engine would be required. On the styling side, Conceição decided that the body lines should be more fluid and modern. The “crate” styling of the Lusito, relatively permissible at the beginning of the decade was obsolete by 1956—it was alright for a prototype but had to be abandoned for a series production unit. The process of homologating a car for series production was not an easy task. Monteiro Conceição, in a lucid memo, wrote in 1956:

“(…) This vehicle travelled about 30,000 km and was dismantled in October 1955 to study the effects of wear and tear on certain parts. We then tried to obtain similar parts to be able to carry out the assembly with standardised components and, consequently, at a convenient price. Among the constituent assemblies that were not obtained from the national industry, the more important were: engine, gearbox, differential, steering, brakes and some electrical articles. The Company had to resort to foreign industry, consulting dozens of houses, noting the difficulty in obtaining pieces that fitted together perfectly, with the need sometimes to propose certain changes. The Company has not spared efforts or expenses, one of the partners went abroad twice to study the subject of parts and to visit the factories of small automobile manufacturers, whose technique differs from the normal manufacturers. (…) ”

From that effort, the IPA 300 was designed with two different body types. The first was a 2 + 2 version and the second was an elegant Coupé. Mechanically, the cars were based on the English Astra, a small commercial vehicle equipped with the British Anzani two-cylinder, two-stroke engine outputting approximately 15hp.

Five pre-production series of the two variants were presented at the 1958 Portuguese Industries Fair. The exhibition was a rather solemn affair whose crowning jewel was the presence of the President of the Republic, Craveiro Lopes and Marcello Caetano. The presence of two dignitaries holding Portugal’s High offices, however, had no positive effect on Monteiro Conceição’s dream.

A 1956 petition to the government from IPA was lost in the realms of the national bureaucracy, and Conceição’s license application for serial manufacture was denied by the then Secretary of State for Industry. The Secretary backed an industrial policy instead, which favoured the assembly of vehicles by other European and American brands in Portugal.

Brochures were still issued for both IPA vehicles but the process came to a firm stop when a regulatory ban was announced which strangely only affected vehicles produced by Monteiro Conceição’s IPA brand.