Thread: 340 to a 392

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Hey im a new member and mabey it has already been discused but as anyone stroked a early 340 block out to a 392 i as cus Speed-o-Motive has a new stroker kit out and i was wondering if it was worth buying of if it would rattle apart my engine in the next month? any one done a stroker of anykind on a 340? please let me know

thanks

Before you throw $$$ at that 340, check out using a new style Hemi V8. The Hemi is available in just about every RWD from MOPAR and utilizes OVERDRIVE. Purchase a wrecked Hemi car/truck and switch over everything including computer. just use the wiring schematic from the donod car. In the long run you'll be Happier with the HEMI.

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

the new hemi is a gutless pig