It's been reported that some HD manual trans trucks with the 400 got forged cranks well into the seventies.
Several years ago I pulled a '78 400 out of a pickup truck with a manual trans. Had a steel crank and the backside of the bearings were dated '78.
Guess it's possible it's 400 forged crank? The truck was 2wd and originally a 318. Would 2WD, 4 speed big block trucks been equipped with a forged crank or was that a HD/4x4 application only?
Seems reasonable to presume the engine came out of a BB manual trans truck since it had the deep, rear sump pan though I have no idea if that was original to this particular motor or not. The truck was from out in Oregon which somehow retains more '70s trucks per capita than anywhere else on the planet so finding the motor and/or parts was probably fairly easy.
Original or not though, the motor was a strange buildup. There were some decent parts in it - aforementioned steel crank, nice recon'd rods with ARP bolts, milled 452 heads with positive seals and M.P. valves, .484" purple cam, Performer RPM intake, long tube headers, double roller timing chain, "Hemi" mechanical fuel pump, windage tray, HV oil pump and HD shaft...your basic '80s style "Mopar Performance" recipe street motor.
Unfortunately the guy kept the stock, low compression pistons in it and put it in front of a wide-ratio, granny first gear NP 435 with 3.23 rear gears which leaves you to scratch your head. The thing it did best was drink gas. It ran OK after a lot of tinkering but it was basically doomed from the start with the low compression pistons.
