T&D 1.7 ratio rocker arms. Part number 8013, 5/8” shaft, paired rockers per cylinder.

I bought a new set of T&D 1.7 ratio rocker arms. Scott Koffel told me that running those rocker arms allow easier springs changes. Rotate the engine so both the intake and exhaust have lash (TDC), and remove the short shaft with both rockers without any spring pressure; Nice. But they will require elongating the pushrod holes in the heads toward the intake manifold side. The T&D catalog shows the #8013 set uses 0.080” longer rocker arms than the typical B1 single shaft per head setup. So that explains the holes needing to move toward the intake manifold, away from the valve side of the heads. And my first mock-up shows the holes do need that work, especially the intake pushrod holes. The heads originally had a 5/8” dia hole for the intake pushrod, and a 3/4” dia hole for the exhaust pushrod. The single shaft per head rockers are simpler to install/setup since they use the regular oiling from the block cam bearing, and little or no pushrod hole clearancing. Scott Koffel said many racers use them without issues.

The #8013 rockers require either pushrod oiling or spray bar oiling, since the steel rocker platform covers the oil feed from the block cam bearing. I plan to run pushrod oiling. The rockers have internal passages to feed oil to the shaft bearing, the roller tip, and a small spray hole to cool the valve springs. When I put them on my heads, the T&D height checking gage showed that using lash caps would put the shafts at the correct height for my 0,800” lift cam. Scott Koffel said lots of his racer’s use the lash caps.

I plan to run 7/16 dia pushrods, and I want the ability to use either lifters with the offset pushrod seat or the centered pushrod seat. So, I am making clearance in the heads for all that. I used a 5/8” dia endmill and moved the centerline 0.125” toward the intake manifold side. That was plenty, and if you did it with a die grinder by hand, you could remove less (with tighter pushrod clearance). Note, the intake pushrod holes are at an angle to allow the wider B1 intake port, especially the pinch point. Also, the 0.125” move is more important at the top, rocker end, since the pushrod will angle back to the same lifter location.