Mopar stroker's are becoming quite common...most are of the 4 inch crank variety that would typically result in a displacement of 416ci with a .030 overbore.

The kit you are talking about (I'm not too familiar with it) must be using the older 3.79 inch crank, or a different, 3.75 inch crank.

Regardless, there are three basic ways to stroke your mopar:

1. Buy a kit with the crank and pistons cheap, and then pay a machine shop a crudload to balance it...usually externally...or pay more for internal balance and have a far heavier crank.

2. Buy a cheap kit with harmonic balancer and flywheel or flex plate already pre-balanced from the vendor...typically uses cast pistons and crank...which is fine for engines that'll live below 6000rpm and make less than 500hp.

3. Buy a complete kit with forged piston/crank, already pre-balanced, good rods, etc.

Obviously 3 will be the most expensive, and give you the most flexibility...but 2 is fine as well. Guys that buy just the crank, or the crank and pistons find that the whole balance procedure can drive the cost up higher than option #2 would have been...despite the very attractive initial cost.

But the stroker kits are great...more cubic inches is always a good thing, because it is CERTIAN to give you what you want more off...and that is torque.

I generally recomend that if you are getting a stroker, head work or new heads altogether is needed. Again, swapping to magnums is probably the cheapest initially and can support over 400hp with the correct cam/carb/headers...stock 340 heads (especially 1973 heads) will run out of steam at around 370-380hp. With some minor work, they could easily support 450+hp of course, but even at this level, it may then be cheaper just to buy a set of eddy AL heads...which box-stock will support 500hp.

Strokers really like larger cams and narrow LSA...so a cam in the 236 @ .050 with a LSA in the 108 range might be a little hairy for most on the street in a stock 340, would be very tame in a stroker 416. I'd probably run 242-255 @ .050 myself, with LSA's in the 106-108 range.

Now, if the kit you are talking about is in fact a 3.79 or 3.75 inch crank, revisions of the cam selection would be in order, of course...

...but if you are looking to rebuild....you can't go wrong with having the engine stroked