Has anyone used the adapters to install the mark 4 crankshaft into the later one piece gen V and VI block?
https://www.jegs.com/i/Stefs/861/7036/10002/-1

Bruce I’ve never used the BB version but have used the SB type. I have the Jesel seal alignment tool on a shelf. It’s just a chunk of steel machined to lay in the rear main saddle and has seal adapter alignment portion.

I have built a Gen VI 502 but used a one piece seal crank.

The small blocks were later model Bowtie blocks. Had to use adapters.

Had no problem with any of them.

Thanks for your input Rich.
I have to non Mark 4 blocks and several 2 piece RMS cranks.
Trying to clean house and figure out how to "market" this stuff.

The 5&6 blocks have potential issues with fit on oil pans and timing covers, if I recall right.

I think they also use a different head gasket to mate Mark 4 heads to those blocks.

I built a street strip 502. New block, new crank Gen VI and Mark 4 oval port heads. Ended up in a Nova racecar and went in the 9’s.

I used Steffs adaptors years back, and as I recall they were kinda easy to use. The had 2 for bbc 7035 and 7036.
and the gasket to use up to about 4.530 was a 1017-1 or -2 . They were embossed with mk 4 and gen 5&6 printoseal.
Gsk bore was 4.540
Hope this helps.

Gen 5 Bowtie blocks use an adapter on the block and a Mark IV cap. I've never seen or heard of a problem with the adapters on the blocks. Of course, the adapters are factory installed and may be in place when final machining happens.