Milodon Main Caps

MAIN CAPS

Main Cap Facts:

While mild steel main caps may look like main caps and are economical, they are the wrong material for a performance application. True "deductile" iron caps take a beating and return to their original shape (deductile) saving the bearings and continuing to perform well. Very rigid mild steel caps act differently and do not absorb the impact from the crank and usually pound out the bearings if run hard. Its like if you had to jump out of a second story window. Would you go for the cement or the grass ? Your crank is thinking the same thing !

Deductile iron caps also cut better during align bore. They heat and expand at the same rate the block material does so the crank bore stays round instead of going oval. These are good things and probably answer the question of: "Why are these caps way less than the price of the Miloodn caps ?"
These Milodon aftermarket main caps will strengthen not only factory 2 bolt blocks, but also 4 bolts. Unlike the factory main caps, Milodon main caps 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% cleanup 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 center three main cap kit. For maximum strength the installation of Milodon main studs are highly recommended.
     
SMALL BLOCK CHEVY MAIN CAP # MAIN STUDS 
w/o windage tray
MAIN STUDS
with windage tray
283-327 Journal (Angled Side Bolts) 11050

81128

81129

283-327 Journal, Front Cap, 2 Bolt 11053 
350 Journal, Factory 2 Bolt (Angled Side Bolts)1 11150

81128

81129 

350 Journal, Front Cap, 2 Bolt 11153 
350 Journal, Factory 4 Bolt (Angled Side Bolts)2 11160 

81128

81129 

350 Journal, Factory 4 Bolt (Straight Side Bolts) 11165 

81131 

400 Journal, 2 or 4 Bolt Blocks (Angled Side Bolts) 11180 

81129 

BIG BLOCK CHEVY MAIN CAP # MAIN STUDS 
w/o windage tray
MAIN STUDS 
with windage tray
396-454, 2 or 4 Bolt Blocks (Angled Side Bolts) 11200 81133 81134 
396-454 (Straight Side Bolts) 11205 81140 81141 
NOTE: 1-Narrow register 4.490" wide... 2-Wide register 6.200" wide... 3-Requires slight pan clearancing at #4 main, Milodon pans will be OK.
FORD MAIN CAP # MAIN STUDS 
w/o windage tray
MAIN STUDS 
with windage tray
351W (Angled Side Bolts)3 11420  81175 81164 
351C (Angled Side Bolts) 11440  81169 81170 
429/460 (Angled Side Bolts) 11450  81188 81189 
CHRYSLER MAIN CAP # MAIN STUDS 
w/o windage tray
MAIN STUDS 
with windage tray
318-340 (Angled Side Bolts) 11300  81183 81184
360 (Angled Side Bolts) 11310  81183 81184
354 (Angled Side Bolts) 11320  81183
392 (Angled Side Bolts) 11350  81183
440 Wedge (Straight Bolts) 2 Bolt 11360  81183
383-400 Wedge (Straight Bolts) 2 Bolt 11361  81183
383-440 Wedge (Straight Bolts) 2 Bolt - 5 Cap Set 11365  81188
PONTIAC and OLDS MAIN CAP # MAIN STUDS 
w/o windage tray
MAIN STUDS 
with windage tray
Pontiac 455 (Straight Side Bolts) 11500  81222 81224 
Pontiac 350-400 (Straight Side Bolts) 11505  81222 81224 
Olds 400, 425, 455 (Straight Bolts) 2 Bolt 11550  81175
AUSTRALIAN HOLDEN MAIN CAP # MAIN STUDS 
w/o windage tray
MAIN STUDS 
with windage tray
253-308 (Angled Side Bolts) 11570 81145 81146