saw your post in the top speed poll that you are getting 413hp out of your 355.........wondering what you got in it for that kind of power.......wanting to do a build upon on my pair and am not convinced about the 383/406s long term reliability........doug

350 CID actually... and yes 413 was the best pull just below 5700 rpm...

comp off the shelf roller *and valvetrain* installed @ -4. proaction 220 cc iron cylinder heads (too much runner volume). 9.4:1 static compression ratio with a .038 quench, rpm airgap, demon carb, msd.. nothing special honestly...

i'd go 383 or 377 (standard bore 383). they are torque monsters, as affordable as a 350 and they will hold together juuuust fine... 450 hp is not out of reach with a healthy hydraulic marine roller...

if it was me.. going brand new 377 i'd go with a NEW gm roller block and a scat rotating assembly.. set it up for 9.6:1 static go with the XM276 or the crane roller, crap, the number eludes me at 11 pm, and keep it simple... i might opt for AFR aluminums since the defunct of Pro... the rpm airgap runs pretty well on my motor too and the demon for a carb is the cats ass vs anything else i've run...

i run the XM276HR.. has a bit of a lope... draws 12 inches of mercury at idle @ 900 rpm in neutral.

383 built right is pretty much bulletproof.. Mine has well over 200 hrs on it at this stage.