Isn't it true that the dog bone lifters are taller than the link style, so the dog bone lifters need the head removed but the link style do not? This is purely off of memory but thought i would throw that out there. Maybe its the other way around
I think either one will need it, I was simply quoting Vic Edelbrock, the Vic Jr.'s were designed so you could remove them without taking the head off, that was the point I was making.
the dogbone lifters are somewhat taller, thats why you have to use a reduced base circle cam, to sit them down lower in the bores, plus the oil hole is too high. The link bar lifters are close in overall height, but the oil hole is lowered, so the lifter doesn't have to sit as far down in the hole, allowing use of a standard base circle cam. With a 351, its likely that either will fit without removing the heads. On the shorter deck 289's and 302's, head removal is required for the link-bar lifters, and I'd say its probably needed for the dogbone lifters as well.
I have a roller cam "retro fit" with the horz. Links (dog bones) that I just replaced. Maybe this will help:
1. A little clean up is needed around the lifter bores to give the "dog bone" enough clearance so it won't touch the side of the block in the down position.
2. The block's lifter valley does need to be ground smooth if a casting mark is present at the two locations of the new holes and drilled and tapped to a 1/4-20 thread. No inserts needed.
3. I can install the lifters w/o removing the head but I have heard the vertical lifters are different as it applies to a “non-roller” 302 block.
4. The reduced base circle cam is needed in a "non-roller" block because the lifters would stick out too far in an unsupported position. A true roller block has taller lifter bores. Hope this helps….I like the roller cams for the reduced friction and steeper ramp angles.
Just the thought of doing a flat tappet cam break in worries me enough that I would go for the rollers if I could swing it. I understand there are tons and tons of engines out there with flat tappets, but I have heard too many horror stories of wiping a cam lobe during the initial start up.
Don't beleive everything you hear, breaking in a flat-tappet cam is pretty much a no-brainer. I have seen a couple cams wiped out by the installer thinking he needs to slather the cam in break in lube. The stuff is very thick and if you use too much it will easily start plugging oil passages. Anyway, my take on rollers is they are awesome cams and allow you to use a much more aggressive grind, but still stay streetable. I don't have one in my car simply because I couldn't justify the cost. Comp Cams has a whole slew of dyno charts on their website and there is pretty much no difference at all in hp or torque for the cam I selected (XE268H) so I saved a few bucks and blew it somewhere else on the car!