348/409 Tune up specifications

Passenger Car Engines

Year	Engine	AC Spark plug	Spark Plug Gap (inches)	Distributor Point Gap (inches)	Point Dwell (degrees)	Timing (degrees)	Intake Valve (inches) C=Cold H=Hot	Exhaust Valve (inches)
early 1958*	348	ACR44S	.035	.016	30	8B	Hydraulic	Hydraulic
1958-60	348	AC44N	.035	.016	30	8B	Hydraulic	Hydraulic
1959	348 w/spec. cam	AC44N	.035	.016	30	12B	.008H	.018H
1960	348 w/spec. cam	AC43N	.035	.016	30	12B	.008H	.018H
1961	348	AC44N	.035	.019	30	8B	Hydraulic	Hydraulic
1961	348 w/spec. cam	AC43N	.035	.019	30	12B	.008H	.018H
1961	409 (360hp) w/spec. cam	AC43N	.035	.019	30	12B	.008H	.018H
1962	409 (380/409hp) w/spec. cam	AC43N	.035	.018	29	12B	.008H	.018H
1963	409 (340hp)	AC43N	.035	.019	28-32	10BTDC	Hydraulic	Hydraulic
1963	409 (400/425hp) w/spec cam	AC43N	.035	.019	28-32	12BTDC	.018H	.030H
1964	409 (340hp)	AC43N	.035	.019	28-32	6BTDC	Hydraulic	Hydraulic
1964	409 (400/425hp) w/spec cam	AC43N	.035	.019	28-32	12BTDC	.018H	.030H
1965	409 (340hp)	AC42N	.035	.019	28-32	6BTDC	Hydraulic	Hydraulic
1965	409 (400hp) w/spec cam	AC42N	.035	.019	28-32	12BTDC	.018H	.030H

* Early 1958 348 heads (#791's) had no cooling holes and would use short reach spark plugs. Later '58 heads and newer went to the long reach plugs.