I asked this question on a LSR mailing list and received these responses so far:
"
Check out www.inliners.org In fact joining Inliners International maybe something he may enjoy. They can lead you to the best suppliers and guys who know a lot about the 194-292 ci Chevrolet/GMC engines...Good Luck "
"
might look at Leo Santucci's book "Chevrolet Inline Six-Cylinder
Power Manual" Lots of parts are available from Sissell, Langdon's and many
others. Most of it stuff I would rather have then Cliffords. You
could also look into Inliners International as a source of inline
information. Many LSR guys are members. RF Inliner #9 "
"
Glenn Self--Self racing engines Durant, OK. has been racing Chevy sixes for almost 50 years--- He has some STUFF and tricks to try to keep them from self destructing at high RPM from VIBRATION!!!!! "
And remember ... the LSR guys are making their stuff last for up to 5 miles per pass ........
And just to back up to my friends build for second .... he is just jazzed as all hell about running an inline 6 cylinder because " It has 7 main bearings " compared to 5 for a V8 .... and this coming from a guy who is a 53 year veteran of the Bonneville Salt Flats and has owned mulitple LSR Records and is a member of the SCTA's " 300 MPH Chapter of the 200 MPH club " .....