[Anthony]

I believe that the solid lifters were made in two configurations,

1) Shell type lifter, with the pushrod seat deeper in the lifter. The lifter is like an inverted cup. They require a longer pushrod than the hydraulic lifters. I think these are lighter of the two versions, and I see alot of people prefer these over the 2nd type.

2) Standard lifter? type, that the pushrod seat is near the top of the lifter, like a hydraulic lifter, so they take the same length psuhrod, or near the same length. This is the type it sems you have. If you can't push on the pushrod end of the rocker to colllapse the lifter (if it's hydraulic), and you're still not sure, you can adjust the lash to 0, and then continue to tighten the lash. Either the lifter will collapse confirming a hydraulic lifter, or the valve will start to open, confirming a solid lifter. If you have a dial guage, you can set it on the valve spring retainer to detect movement.

I don't have a lot of experience with these engines, I'm still learning.

The other thing is the cam design type. I think hydraulic cams and solid lifter cams have different design style ramps and base circles, as the hydraulic lifter has always 0 lash. The ramps on the cam I think are designed differently to accomadate this, including the valve closing rates as well. I wouldn't run mixed parts, as you may damage the valves and seats. Cam manufacturers always state that you can't mix the parts.