Decided to rebuild the 340 along with the 455. Wanted to know what mods are needed to install 350 pistons and rods? Also anyone use the Crane valve seals and cam for the 340? I see several are runnng bigger valves, is it worth the cost of just port matching and valve job good enough? Thanks, Clyde 67 Special 67 GS 400
340/350 In order to run 350 pistons you must bore to 0.050" (fifty) over. Be careful the shop does not hear 0.060" over. At 0.050" you can use std bore 350 pistons. The rods drop right in with no change. Recommend you use the late model 350 rods with ARP bolts. They are stronger. Same bearings. As there are currently no aftermarket manifold for these cars, about all you can do is port match intake and exhaust manifolds. I am not sure bigger valves would be worth the money. Others may have more to say about that.
