It means it's pretty well worn out. It's .030 undersized on the rods, .040 under on the mains.(or vice-versa)

 

The bottom Line is whats your intended use for this build ?? If its a weekend thrasher, Cruise ins, some light to light action...Some ***** out gear slammin..and official tire frier of you city...

The 410/416 with a large stroker crank will do that job and more...in a shoter distance on the street....alot of guys get crazy with the stroker and forget you need some bore up top to push that mass around also...

Since I moved South after 38 years in SoCal in 1/4 mile tracks where BB ruled, the 1/8 mile tracks are more like street racing block to block...and the big inch engines dont always when out....as it takes awhile to spin those mass's up..

But a good way around that is a square build where your bore and stoke are almost the same... hence a 4.080 bore and a 4.125" stroke... 4.160 bore and a 4.250 stroke..If your looking for more TQ..and want the R's to come on fast!! and have some top end in the build... Now if your looking for a stump puller stay with a 4.080 bore and throw in a 4.375 stroke crank you wont have much in the rpm range depending on cam "maybe" all the hp in at 5500 to 5800rpm...But with a set of 3.00 out back it'll still make so much Tq....you could fry the tires of almost at will in any gear...

The FE I'am looking into doing next is a reverse image 105 block, 4.080" bore with the 4.125" crank, and with a special ground cam and some head work I should be in the 7000 rpm range for max hp with the Tq max at 5500rpm.. But that said ..this isnt your Dads daily driver...weekend worrior only..with some street time to the cruise in and to the Car/Truck club meets..

And Just on a foot note thats with a 4:88 rear gear and a 4 speed...Not for the faint of heart...LOL....

RJ

 

P.S. Simple rule of thumb..... X bore short stroke less Tq, More rpm....X bore Long stroke, More Low end TQ , Less rpm.... On N/A engines...Forced induction are a totally diffrent animal....

Look at Nascar.....Big bore short stroke 358 CI....850hp at 8 to 8500rpm depending on the track and gears...there not worried about Tq at running 200mph all day.. that why it takes them a lap to 2 laps to get up to speed... JMO

And in Drag racing the TQ gets you off the line and your HP makes the MPH at the traps!!

RJ

 

nothin wrong with a 390, especially with edl aluminum intake, heads and other goodies. that said, a 410 is better. 20 more cubes, longer stroke, more torque. You could put a little bigger cam in a 410 to make better use of your new found displacement. i had a 360 in my f250 when i first got it, all stock 2barrell carb, nice running motor. Moved on to 390,mostly stock with aluminum intake and 4bbl, better than the 260 by far. added 428 crank (3.98) bored .030 (416ci), added comp cam and this motor will spank my 390 anyday. if you have a 428 crank use it. if your just looking into it, and you dont need a racy motor a 390 provides ample power in a street driven/tow rig with mild build, but if you think you want as many cubes as possible and you are considering a stroker crank, for money spent you could easily get more than 410 cubes, up to about 450 or so. depends on how serious you are about it