Quote:

How exotic do you think it would need to be in order to get that type of power? Also, if I had to purchase a 360, motor mounts, flex plate, converter, for a 360 build, what would the total price difference come out to be in building the 390 versus the 360?

Thanks
roe



you don't need motor mounts, $1 in washers used as spacers will allow the use of a 318 drivers mount. pass mount is the same.

B&M flex plate is $80 to be able to use a neutral converter.

around here you can get core 360's for about $300-400. you probably can find a core (not running) mag 360 for about $500-600.

on the 390, if you're going cast crank, you'll probably want to balance it to 360 specs anyway so you don't have to spend a boatload of money on mallory to balance it, so you'd need that weighted flexplate anyway.

IMHO the only reason to stroke a 318 is to use a hydraulic roller cam cheaply, especially with LA heads. 318 roller cam blocks are easy to find (any 85-up M body in a junkyard) compared to 360 blocks. if you're planning on running a flat tappet, just start with a 360. pistons and rings are cheaper. if you plan on a hydraulic roller cam and mag heads, you're probably money ahead just picking up a core mag 360, again, pistons & rings are cheaper, and if you stroke it, cast cranks and stroker pistons are cheaper than a 318.

according to comp's camquest software, a mag 360 with KB107 pistons at 0 deck (10.8:1 comp), a little port work as outlined by dulcich in a 2005 article in mopar muscle, headers, an RPM air gap type intake and a comp XR265HR hydraulic roller cam should be 400-425 HP and ~440 lb/ft tq, and plugging the info into the dynamic compression ratio calculator at kb-silvolite.com, it should still work on pump premium.

heck, 375hp/400tq should be possible with a mag 318 with the same recipie as above, but use KB167's at 0 deck.

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