Holden 253-308 4 Bolt Main Cap Set MI11570

(Angle Side Bolts)

MI11570

11570

These aftermarket main caps will strengthen not only factory 2 bolt blocks, but also 4 bolts. Unlike the factory main caps, these not only have more cross sectional strength, but the real strength secret is in the angled side bolts! The 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 side bolts heavily load the main cap against the register step which stops "cap walk". It is main cap walk that causes a great amount of unforeseen bearing damage and horsepower loss. Milodon main caps are precision machined from high strength ductile material which has the proper balance of strength yet is not too rigid like a billet main cap to allow transfer of increased shock loads to the crank and bearings. In this case, more is not better when it comes to hardness. Only .030" of material removal is required upon initial installation, which will allow 100% clean up on a damaged block. The drill bushing used to drill and tap the side bolt holes is included in the kit. 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 cap registers are not square. All necessary bolts, washers and the drill bushing are included in the centre three main cap kit. For maximum strength the installation of Milodon main studs are highly recommended.