Milodon Ductile Steel Main Caps
Milodon Ductile Steel Main Caps
Milodon main caps are precision machined from high strength ductile material, which has the proper balance of strength, yet is not too rigid to allow transfer of increased shock loads to the crank and bearings. In this case more is not better when it comes to hardness.

These aftermarket main caps will strengthen not only factory 2 bolt blocks, but also 4 bolts. Unlike the factory caps, these not only have more cross sectional strength, but the real secret is in the angled side bolts! These side bolts are angled so they pull from the side walls of the block and not the flimsy main web area. A bolt that is angled will require a massive amount of additional load to flex or stretch, let alone break, compared to a conventional straight up bolt.

The drill bushing used to drill and tap the side bolt holes is included in these kits. The side bolts can be installed by anyone with a hand drill and a tap. If the block has square main registers, the block needs only a standard align bore to finish the job. Milling the mains is only necessary if the main registers are not square.
     
Part #
Manufacturer
Product Name
Price
MIL11180
Milodon, Inc.
400 SB Chevrolet Main Cap Kit
$245.99
MIL11150
Milodon, Inc.
SB Chevrolet 2-Bolt Factory Main Cap Kit
$245.99
MIL11160
Milodon, Inc.
SB Chevrolet 4-Bolt Factory Main Cap Kit
$239.95