That last answer doesn't seem to know much about Celicas. You don't have to spend that much money. Here's my favorite website on the topic:
http://www.toysport.com/technical%20...tech_notes.htm
Someone asked the same question about an older Toyota truck as well. Everything that alpplies to the Truck applies to the pre-1986 Celica as well. you can upgrade it to a 22R or fuel injected 22RE. You can even upgrade to the fuel injected turbocharged 22RTE. Also you will see stuff like just a head swap from another vintage getting good results. Go faster? You bet your life it will.