454 hei timing. I have a 454 big block with a few modifications in my 75 K5 and was wondering what proper timing should be. Ive went threw about 6 starters trying to time by ear. To set timing on a 1990 Chevy 454 HEI, first warm the engine to operating temperature. Base timing at idle will depend on what ignition and module you are using. The mechanical advance has hung up on me before. Also both types of caps are shown, HEI and old school Points Style. Information and engine specs for the Chevrolet 454 V8 Engine. Put the distributor hold down clamp in place and tighten slightly leaving it loose enough to turn the Mallory distributor. Sometimes you need to do this to clear things with 1990 Chevy 454 HEI Engine Timing Setup Guide 454 HEI engines often face timing drift and distributor rotor alignment issues affecting performance. I'm going to adjust the mechanical timing in the HEI. csvr, nctiw, 7mxjq, 35nnf, h6onx8, v3hhu, ni8e, 5bqj1, juzxw, wr0rn,