Any ideas?

no!!!

The journals are different, you have to get an aftermarket crank thats 3.58 stroke with the 340/318 main journals. The 318/340 mains are smaller. Scat, K1, Eagle they make one, callies also.

Or you can cut the 360 mains to size when you have it crank turned. usually 80 to 100 extra.

Will the crank handle that much of a cut??

I have never thought of doing that because of strength, but I suppose it would live. We are useing a callies ultralite crank in my little stroker build.

Kasey

People used to cut down 360 cranks to put in 340's all the time. There is no reason why you can't do it for a 318 (same main size). I'm not sure if I would do it on a killer high HP motor, but nothing wrong with doing it for a street motor.

Overlap really isn't a problem. You'd run a cast 4" crank with a 318/340 main right? So why not run a 3.58" stroke?

The problem is the piston skirt hitting the counter weights. AMHIK !!! Some one may now make a piston for this app.

Diego

I did that back in the early 1980s in a 340 block, that motor is still running. I used a Speed Pro 360 forged race piston(13.0 to 1 comp) and cut the tops off, had the crank assembly nuetral balanced and put it in the car The thing about the 318 bore is that it may end up needing a custom piston made for that stroke, which is of course is more money than a standard off the shelf piston another option is to offset grind the 360 rod journas to big journal SB Chevy rod size, use aftermarket Chevy H or I beam 6.25 long steel rods and increase the stroke to make a bigger C.I. motor, which will end up making a lot of torque

I've got a new mopar crank that you are looking for, i'ts for sale $275+ freight,jg309 or 618-806-1546 after 12 noon

streetwize is building a combo like this. he's using 6" rods and KB167 pistons to get 0 deck. other piston combos to try would be 6" chev rods and KB165's (283 pistons, same CH as the 167's, but w/a SBC pin size) in .040 or .060 over (would be .005 or .025" over 318 bore) this will yield ~10.2:1 with a .040 head gasket and 64cc heads.

or 6" rods with these 283 pistons which would end up ~.030 in the hole using a 9.6" deck height. this should yield ~10:1 with a .028" gasket and 64 cc heads.

or run a 6.25" chev rod and these chev 250 I-6 pistons with .080" cut off the top to have a very slight dish and 0 deck, which with .039" gaskets and 64cc heads should yield ~10.2:1 comp.

or chev 6.25" rods and some KB2228 pistons for a jeep 2.5/4L...this will net .020 above deck for blueprint 9.6" deck height, so either mill .020 off, or run the standard .054" thick fel-pro gaskets for tight quench...jeep wrist pins are .003" oversized compared to chev wrist pins, so you should be able to hone the rods slightly to fit them. these have an 11.5cc dish, so as is w/a .054" thick gasket, it'll yield tight quench and about 9.6:1 compression with a 64cc magnum head.

283 pistons, the valve reliefs will probably be in the wrong spot, and the 6cyl pistons I listed, there are no valve reliefs, so you're probably somewhat limited in cam selection as far as lift/duration.

the only reason to justify all this mickey mousing around though, is if you have an '85-up 318 block set up for a hydraulic roller and you plan to run one. otherwise, just look for a 360, to be honest...you can find magnum 360's pretty reasonably, and they also run hydraulic roller cams.

Lots of good ideas, and I was way too vague on my project, sorry. I have a 1971 Dart that I am building street strip,(low 14's)for my Granddaughter, and I have this 1970 318 with 50,000 miles on it(it's been sitting forever)I have 71 360 x crank, I have h-beams (scat)6.123 , racer brown hydraulic cam, 1971 340 thermoquad and intake, magnum heads, 360 magnum block, lot of stock rods, 7 mahle pistons from a magnum crate motor 360, (1 was lost by machine shop)and numerous other 360 parts. I thought it would be fun to build a mild 318 that would run low 14's that a girl could drive easily. Thanks Dan

Man, Id put that magnum together, buy 1 piston, and build that up. Take advantage of the hydraulic roller cam set up, and buld a decent street/strip car. That would be fun, and easily dip into the low 14, high 13's. That would be your cheapest seeing you already have the H beams, and a crank.

Just my opinion..

Kasey

get the roller cam reground by bullet racing cams, use hughes 1110 springs w/ some junkyard 2.2L retainers, keep lobe lift ~.320 (~.512 at the valve).

have one ging together right now. biggest expense in cutting the crank is the seal area and slinger. were using a 318 piston and a 307 olds rod (left over from a stock eleminator build up) the crank just touchs the piston. we will cut them for clearence and rebalance. the piston sits bout .04 in the hole.

360 all the way