Main Cap Support Girdles
Strengthen the bottom end of high powered Ford 6 cylinder SOHC and DOHC engines by adding an Atomic main cap girdle. Precision laser cut from billet steel and precision CNC machined, our main cap girdles are designed to tie all 7 main caps together to increase structural integrity of the block and main bearing caps. One major feature of our girdles is that they fit! No need to notch and weld the sump to make it fit, and with at least 4mm clearance to the conrods Atomic girdles fit with std or aftermarket fasteners whilst retaining the correct bolt purchase into the block. We have seen some cheap copies of our girdles that are not contour-milled for conrod clearance or counter-bored, so either the conrod hits the side of the girdle or the bolts do not go all the way into the block!

Main cap girdles are a vital component in engines producing over 400Kw at the tyres, as the main caps begin to “walk” on the block at this power level and beyond. Once this occurs, the cap no longer provides accurate bearing alignment for the crankshaft, leading to premature crankshaft and or main bearing failure.

Available in two models, for Street/strip use (up to 698kW) or for all our Race applications, both girdles come with a louvered OE style windage tray. Installation is by way of the original bolts or with an Atomic #306670 or #306671 Main stud kit.



#306250 - Atomic main cap girdle
16mm thick suit BA-BF Ford 6 cyl Race applications - minor sump modifications may be required

#306251 - Atomic main cap girdle
10mm thick suit BA-BF Ford 6 cyl Street application - will fit standard sump without modifications

#306252 - Atomic main cap girdle
16mm thick suit EF-AU Ford 6 cyl Race application - minor sump modifications may be required

#306253 - Atomic main cap girdle
10mm thick suit EF-AU Ford 6 cyl Street application - will fit standard sump without modifications

#306254 - Atomic main cap girdle
10mm thick suit FG-on Ford 6 cyl Street application - will fit standard sump without modifications

#306255 - Atomic main cap girdle
16mm thick suit FG-on Ford 6 cyl Race application - minor sump modifications may be required