adding a roller cam to a vintage ('69) block

[SAC69]

If I add a roller cam to my '69 351 block, do I use the $400 "retro-fit" link-bar roller lifters with a regular roller cam? Or do I use the newer-style spider retainer with the dog bones that hold the lifters in place? Which one requires the use of a "reduced base circle" cam and why is that type of cam allegedly a problem? What exactly is a "reduced base circle" cam? Is it a smaller diameter to keep the lifters from rising to far up in an older, shorter lifter bore?

In summary, what is the best route to add a roller to a older (69) block?

Thanks.

 

[Fst Blk]

The link bars are the proper way to do this. Reduced base circle cams introduce too much harmonics into the valvetrain.
Bill

 

[SAC69]

Ok, so if I buy the link-bar lifters, I can shop for any roller cam that's NOT part of a dog-bone kit? It's the dog-bone kits that have a reduced-base-circle?

 

[Fst Blk]

If you buy the link bars then you can use any roller cam. You will not need the reduced base circle. The reason for the reduced base circle with the dog bone and spider hold down is that the lifter is too long for a non-roller block. The reduced base circle keeps the lifters in the bore.
So, yes with link bars you can use regular roller cams made for late model 5.0's and such.
Bill

 

[SAC69]

Ah, ok. Thanks.

 

[66benchcoupe]

What I've learned is that there is a height difference in the oiling hole location in the lifter bores on late model roller blocks which is why they make the reduced base circle cams for the early blocks. I've measured some old and new blocks and have found differences, mainly the oiling hole being higher in the lifter bore. Sorry I don't have any numbers for ya, I have no idea what I did with that data. Suprisingly, there's actually more lifter bore on the older blocks than the new, maybe because the tops of the lifter bores are machined flat on the late model blocks. My opinion is that the oiling hole location could potentially be a problem with standard higher lift roller cams (like over .520 with a 1.6 lifter) at redline RPMs.

Link bars are the way to go for roller lifters, there's not much holding that spider down in the lifter valley. But the spider and dogbone is the economical way to go for a street car. I had no problems with the spider and dogbone assembly on my '66, which had countless 7000 rpm shifts. . .

Robert