COMP Engine Bearing Spacer Set (CO5620)CHEV SBC MAIN BEARING SPACERS Adapt SB Chev 350 Crank Into 400 Block Part Number: CO5620 These bearing spacers from COMP Cams allow 350 Chevrolet crankshaft installations into 400 Chevrolet blocks. Absolutely no machine work is required for installation, simply snap them in and install standard 350 bearings. You save the cost of buying thicker, more expensive bearings. We have had thousands in use for over 20 years without failure.