Dream it... Drive it... Built by JBA


Large AMC logoIn original AMC form “the mighty engine that could” is the theme anyone that has faced a 390 AMC on the street or track remembers. The reputation as a beefy light weight motor that is strong and makes big power is continued at JBA Performance Engines.

Externally other than casting numbers AMC engines can confuse the most interested competitor. With external dimensions consistent in looks the 290 and 343 small blocks respond to JBA cylinder head work and blueprinting if restoration is the goal.

For power and reputation the 390 and 401 engines offer interesting combinations that can be maximized using stock parts progression including original pieces but also respond incredibly to the aftermarket strength of H-beam rods and full floating pistons.

Dogleg heads and big vales support the high flow and big horsepower characteristics of the 401 with more radical JBA camshafts or mild street grinds for high torque. Early 390 to 401 combinations are equally enhanced when the big valve heads are utilized on custom combinations. Aftermarket steel crankshaft balancing or balancing of original crankshafts perfects the external factory crankshaft smoothness for high RPM operation while the option of internal balance of steel crankshafts is also available at JBA

The tall deck blocks found after 1970 will support the early heads with allowance for JBA modifications for the stronger ½ inch head bolts. Oiling system special treatments include blueprinting of the external oil pump improving higher RPM reliability. Lifter valley passageway drilling, tapping of lines and re-routing secures the oil flow to number 4 and 5 mains. This is a further JBA blueprint specialty to allow high horsepower applications to rev to the max.

AMC Engine Families:
390, 401

Some of the products and services offered by JBA Speed Shop are intended for racing and off-road use only. JBA Speed Shop is
not responsible for products and services it provides for racing or off-road use vehicles that may be driven on the street.

JBA Speed Shop · 5675 Kearny Villa Rd · San Diego, CA 92123 Local: (858) 495-3395 · Toll Free: (888) JBA-5570 · Fax: (858) 495-0954
Copyright 2009-2014 JBA Speed Shop, a dba of J&J Performance Center, Inc. All rights reserved. · info@jbaracing.com