67 skylark instrument fuse = 4 amp fuse. Ive been using the instrument fuse to run power to my tach. old school super tach 2.. Its the only source I can find to run the tach ignition on, Accessory off. Play radio no motor running.. Would I be pulling to much power to run the AEM 30-300. To me it seams to be the best 12v source. I don't really under stand just what the instrument fuse protects..... The idiot lights or the speedometer, dashboard lights.. Ive never over amped a fuse before unless really need. Would replacing the 4 with a 5 be pushing it? Could also a 30 amp relay if needed using the trigger off the 4 and source..