Mopar Performance is now selling 4" stroker cranks for the LA's. Turns a 318 into 390, a 360 to 408 cid. According to Speedomotive, 400-450 torque and hp easy; streetable and with a pretty mild cam. They machine 4340 cranks for $795; got a price from Six-Pack (local Mopar Performance place) of ~ $300 for their cast one. No price available yet for the Mopar 4340 crank. Uses 360 rods. For a 318 block the pistons have to be custom forged units, but for a 360 Keith Black hypereutectics are available. Sorry if this is common knowledge, but it's new to me. Any experiences, comments?

Thanks for the info.
Anything for the 4.7????
I'm guessing no......
BTW, the 318 isn't going to be offered on any new models from now on.

I don't know squat about the 4.7, but am guessing it's bottom end is the same as the old LA's and the two larger Magnums. If this really is the case, shouldn't be any trouble to stroke one of these too. They've got a family of these cranks; there may be a different one that's better suited to that engine than the 4.00 stroke. These newer ones are largely outside my experience; I used to think that I knew something about the older ones, but that was some time ago.

i would put one in my heep, just that i have marginal cooling as it is. guess i'll just have to put one in my 64 cuda!:D

I screwed around with Desktop Dyno a little. Given one of their default cam profiles (278* duration, 0.476/0.452 lift) a single 4-bbl carb, and some head work, we're looking at the mild-mannered 318 returning 414 hp @ 5500, 427 lb/ft at 4000, and it still has 380 lb/ft down to 2000. :D For the same thing starting with the 4.00 bore (360 block) it's 430 hp, 436 lb/ft, and right at 400 lb/ft @ 2000. :D

Yeah, that has been out for awhile.. Mopar muscle has been doing a build up on a 360 with W2 heads for awhile now, this current issue is where they finally put it on the dyno... it got 607.5 HP @ 6300 RPM & 552.2 @ 4900 RPM with a MP tunnel ram dual carb setup, and dual 750 demons. With a single plane MP intake, and a single 850 demon it produced 583.9 HP @ 6300RPM & 533.8 @ 5200RPM.
Both times they had to fatten the jets, and with the single carb, they said they wished they had a BIGGER carb.. just think about a 1050 on top of this motor... I believe it would use all the fuel too.

Not Bad Power.. and I love the low RPM torque, although, this motor is all built with 10.5:1 compression (to be street) .. but it does have .420 lift on the cam, which is way too much for a wheeling truck.

I have personally been wanting to build one of these for awhile now.. my plans would be as follows:

360 Block Bored over
4.00" stroke MP crank
Eagle rods
Keith Black 10:1 compression pistons,
Edelbrock OR W2 Heads
Edelbrock Performer intake
Holley Commando 950 Direct Port injection fitted for the Performer intake
Small cam, probabally about .267 to .285 lift (I believe thats it)

I think with this setup I could get kick ass power, plus have alot of power under 4k (which is where i want it), but will still spin my 35's with 3.55's awesome for mud and sand (more RPM @ the wheel).
Also, I thought that the 4.00" stroke crank Required different rods?? Am I wrong??
I also plan on putting in the smaller (I believe 3.85" stoke) In the 318 in my 96 Ram if I ever have to pull the engine. But I hope (knock on wood) that isnt gonna happen any time soon.
Hey lloyd, think you could pop that combo into desktop dyno to see what kind of power I would be pulling if I put this motor together?? thanks

Garrett

PW, your cam lift (0.267 to 0.285) is wrong. Even a stock cam has more lift than that, and there's no benefit at any speed from cutting one that short, unless you're strangely obsessed with extreme valve spring life. I think you mean 267 to 285 degrees duration seat to seat, which is a reasonable amount for this type of engine.

I'll run desktop dyno for ya, but what you've specified is really no different (except maybe the cam) from what I already gave results for. In order to input a cam profile, the three basic pieces of information I'll need are duration, lift, and lobe centerline angle. To really do it right I'll need the valve open and closing points relative to TDC, but those are harder to get correctly without contacting the manufacturer for the full spec. sheet, and there's a workaround using the LCA.

Carb size is easy to figure. Engine displacement in cubic inches, times maximum desired rpm, divided by 12*12*12*2 (3456) gives needed CFM. Always add an extra 10%. For example, a 390 @ 5500 only needs 682 (OK, 700) CFM so a Q-jet will work just fine. That 1050 you suggested on a 408 will allow it to turn 8900 rpm, assuming the cam and exhaust are both up to it. Great for the dragstrip, but probably not so hot for a rockcrawler, since the cam profiles that work at that speed usually won't idle below 2000 rpm and don't make any power below 4500.

the .420 cam lift times the 1.6 rocker ratio = the .672 valve lift that monster has.:p