3.8TransAM

I give up.....................

Best I can come up with is M10 - 1.50x 30mm.

Also found M10 - 1.50x 25mm

Can someone here positively confirm the correct bolt size for me(98 LS1)?

Also were all 4 holes used in the 4th gen applications or just 3 per side?

I have new GM mounts/clamshells, but since it was all missing I have no bolts and online searching is proving inconclusive, although I do think it would be one of the choices above. (course if my nephew didn't have my tap/die/gauge set I could check it myself)

Thanks in advance

Pocket

iTrader: (24)

The thread is M10x1.5mm, same as any M10 bolt on a LSx engine. LSx use 4 bolts per side on most applications

Grab an accy bolt and bottom it out in a mount boss, then mark its depth. Remove and measure. 25.4mm=1"

IIRC they're very short bolts, maybe not even 1". Worst case scenario you would need a few washers to take up the difference, or just grind the excess length off

FWIW, Id grab a metric tap/die set if you plan to continue playing with LSx engines. Ive used the same cheap harbor freight set for years. Never know when a bug will pack a hole with mud or a rusty bolt needs to be chased

Also, you box should be there today or tomorrow