Domed pistons

What 5-speed?
Ima thinking the 5-speed is gonna be the weakest link.
Since you didn't say; Ima guessing that Howards is 248/248 advertised. Ima thinking that's gonna be the wrong cam for this application. But what do I know.
You got a link or picture of those pistons?
I think I know what you are trying to do, and with a 318LA, it's kindof hard.
Sorry the duration is .248 @.050 the advertised duration I believe is. 308 id have to look at the cam card to be exact and its the NV4500 . Here's a link to the pistons KB Pistons Engine Piston Kit KB399KTM.020; 3.930" Bore 6.0cc Dome for Chrysler 318 "LA" Mopar