using mechanical pump?

318willrun said

But if you order "any" LA roller cam, isn't there a difference in rocker arm ratios?? What does that do for the lift? And if this is the case then, couldn't a cam from a '86-91 (rollers) LA work? They all have the mechanical fuel pump eccentric already on them (at least my '89 360 does).

Click to expand...

couldn't a cam from a '86-91 (rollers) LA work? Yesbut they don't have much lift or duration.

On the comp specs or any cam manufacturer, look at lobe lift and multiply by 1.6 if using magnum rockers.
You end up with same duration as an LA roller with more lift. No need to go crazy on lift if stock OEM magnum heads are used. Piston to valve and retainer to valve guide seal clearance needs to be checked depending on your combo.