Yes, with the old Isky E-4 solid lifter cams so popular in the 1950s (mine is very similar, I even used an E-4 exhaust lobe), the 6005 dual springs were the recommended springs. They must be installed at 1.750" rather than 1.80", so with 1.7 rockers, I want to make sure there will not be coil bind. I am also looking through various PACalloy springs of similar pressure and installed height to see what they have.
I found some LS type beehive single springs in Isky's online catalogue that were of the same required pressure and installed height. Ran both of these (the 6005s and the beehive springs) by Isky when I called in my specs to have the cam ground. They were of the opinion that a dual spring of same pressure and installed height would give better valve control, especially with 1.7 rockers and the beehive single springs were more a way for OEM manufacturers to cut production costs than anything.
On the 292 inline 6, I am running early year OEM long slot high perf. BBC 1.7 stamped rockers on 7/16" ARP big block rocker studs, Wyrmrider. Was fortunate to find NOS parts on e-Bay. Had to piece a matching set with same code stampings together from 4 sources, as no one had 12 of them.
No performance advantage running roller rockers on a Chevy with less than 0.500" lift and a fairly mild cam. Also, this being for a road car, not a race car that will have its engine torn down and freshened on a regular basis...... Roller rockers tend to have issues around 60,000 miles. Especially the small diameter roller tips. Needle bearings were not designed for such use (concentrated load on only a few needle bearings rocking back and forth). They were designed to rotate fully around a spindle and at that mileage, tend to come apart or need replacement (which costs as much or more as new roller rockers).
So I decided to stay with stamped rockers on the Chevy. The 360 Chrysler will get Crane adjustable rockers that appear to be copies of the 273 adjustable types. Still piecing the MOPAR valvetrain parts together. On the small block MOPAR shaft rockers, there is no oil pumped up through lifters and pushrods unless you substitute .904" AMC lifters and custom length tubular pushrods. Rather, they oil through block and head passages to the rocker shafts. Was wondering about ways to better oil the cups at upper end of 273 type pushrods needed for these Crane 273 type adjustable rockers. When I was a kid, the Ford Y-block guys would run an 'oiler' made of small diameter copper tubing with very small holes drilled in it and fasten it to the underside of their valve covers so it would oil their rockers. Wonder if that might work for the 273 type adjustable rockers? Or has anyone successfully used AMC lifters and tubular pushrods to better oil the cup end of the 273 type MOPAR adjustable rockers?
Thanks for the tips. Much appreciated.
Best regards,
Harry