Well, I dunno if you'll have much luck finding a V4 engine to put in it, but I can suggest some inline 4 cylinders. I'll start with the easiest platform to install. The H22A, which comes out of newer model vtec ludes is a very popular swap for the 3g lude. Many companies actually make bolt-in kits for this engine. Next would be the b16a, which comes out of the 99-00 Civic Si. Another highly popular swap with the 88-91 prelude Si's is a JDM spec B20A (U.S.'s B20A5, which is the one you have in now.) This has about 15 hp more than the U.S. spec B20A5. There is a website that can get you that motor plus all the installation hardware needed for under 800 dollars. 6 cylinder wise, I'm sure the V6 Accord motor would fit in, but it definitely would not be easy. You'd have to cut alot of sheetmetal out of the engine bay, and plus it would make the ride of your car horrible. I hope this helped in some way. If you want to make the engine you have in there now run better, then contact gude, and get one of their performance packages, then get a 100-150 shot of nitrous. You'd be eating SS camaros for lunch!
