Mark VI roller cam into a Mark IV block ?

[TJS]

Ok I have a question. I have a Mark 4 BBC LS7 block. I have decided to go roller cam. I have been reading The Big Block Chevy Marine Performance book and came across a paragraph that talks about putting a MarK VI roller cam into a Mark IV block. Basically it states to get a Gen VI upper gear (machined for the stepped Mark VI camshaft and bolt pattern) and then use a thrust plate from a Gen VI block, because all BBCs have provisions for the thrust plate as mine does. So my question is, if I get a Gen VI roller camshaft then do I still need the comp cam Retro Fit roller lifters (CCA-887-16) or do I need to use lifters from a factory Gen VI BBC. I am thinking still the retro rollers for this.
Right now I have a torrington bearing set up behind the upper gear and I also have a thrust bushing for the timing cover set up to about .008 clearance.
This is what I had for the regular hyd. camshaft.
Thanks.
T.J.

[BOBALOO]

You must use the retrofit rollers because the gen VI lifter bosses in the block are cast flat to accomodate the lifter tie bars. The MK IV bosses are rounded and the tie bars dont sit flat.

[BOBALOO]

http://chevyhiperformance.com/techar...mage_small.jpg
There are also threaded holes in the lifter valley to attach the spider that holds the tie bars in place.

[pce680]

http://www.sallee-chevrolet.com/Chev.../24502502a.jpg
There are also threaded holes in the lifter valley to attach the spider that holds the tie bars in place.
Thatis not Mark 4 LS-7 block.Its a Bowtie

[MACHINEHEAD]

Why bother, unless you have extra gen 6 stuff laying around! BTW I have also done this with spare parts and retro lifters.

[TJS]

Why bother, unless you have extra gen 6 stuff laying around! BTW I have also done this with spare parts and retro lifters.
Ya I was looking at the possibilities and I would have to get the upper cam gear (which I do not have) and I already have a new Mark IV cam gear. I would also have to get the block plate (no big deal). I have decided just to do the roller with the Mark IV stuff. Thanks for the responses.
T.J.