K – here’s unconventional and maybe controversial suggestion for repairing/sleeving cylinder #8 in your fh drag engine to help it survive.
First off, a sleeve in a fh is okay, the closer to stock cylinder bore, the better (e.g. a sleeve set for 3-3/16” piston diameter more desirable than 3-3/8”). Increasing piston diameter reduces both cylinder wall and important casting connection top and bottom (makes fh engine block more fragile).
Not sure of your current French fh engine bore, I’m guessing it’s not stock and possibly 3-5/16? To help your engine survive more abuse (6000+ rpm), you may consider putting a smaller 3-3/16” custom piston in cylinder #8. That minimizes material removal for your 0.125” thick sleeve and helps maintain more of original block casting strength. You’re thrashing engine for only seconds (should work).
Avoid sleeving the other 7 cylinders if not needed. Factory casting is better foundation to have with your fh drag engine. More factory casting remaining in critical locations, the stronger your engine block (so protect what you have).
I found out sleeve in merc block (59 style) worked fine in a street engine. However, the sleeve was installed improperly (top edge below the deck) and still worked trouble-free for many many years/miles. Merc engine was finally replaced when it developed a water leak not related to the sleeve. Based on this observation, sleeve okay with me... DF
p.s. one nonconforming piston rare, strengthwise “provocative”
p.p.s. Tim – that website useful.
