Crank has different bolt spacing on flange, same as a camry, also has different oil cooler mounting. has mechanical rather than automatic cam belt tensioner, heads tend to crack under the intercooler mounting foot (I had two both cracked in same place.) I think theis is only a problem with a top mount ic. The heads can flow real well if ported just like a gen2. The shims are shim over like a gen 2, but the shims and buckets are the same as a 4age and smaller. There ARE aftermarket cams ATS has three different grinds. The rods are weak in a gen 1 too, not beefy like a gen 2.