340 Stroker

[CB Freshness]

I'm new to the forum and 20 years old. I have a 68 charger that I'm building an engine for. My plan is a 340 stroked to 416 with aluminum heads and a 6 pack intake. I haven't seen this done to a 340 and I was just looking for any wisdom or advice anyone had. Are there any issues I need to watch for. I plan on porting the heads and intake as well

[Troy]

Do you have an engine yet? If not, I'd suggest finding a (older) "LA" 360 or even a newer Magnum 5.9 to build as a stroker. Reasons:
1. A 340 is expensive to start with. They are limited production and somewhat difficult to find in good shape.
2. There are many reports that there just isn't enough material in the 340 block (or core shift) to increase the bore/stroke without compromising the engine. The last thing you want to do is pay a premium for a block and then realize it's unusable. I should point out that most of the time when I have seen this complaint it's due to a large stroker kit - not necessarily the most common.
3. Once the thing is built hardly anyone can tell the difference between a 318, 340, and 360. Unlike big blocks, the numbers aren't clearly visible.

With the aluminum heads and Six Pack intake it doesn't sound like you're shooting for a budget build - but there's no point in spending a lot more than necessary. You're changing everything except possibly the "tin" so start with the best block available. You can pick up 318s for almost nothing and 360s for about half (or less) the cost of a 340. A "common" 318 stroker is 392 cu in and the 360 is 408 - although both can be made larger with more work and more money. They'll all put down a lot of power!

Troy

[CB Freshness]

I'm taking out the original #s matching 318. I good friend of mine has 12 mint 340 blocks that I'm gonna get.

[Troy]

Well, that's good. Most people don't have that kind of access. The 340 has smaller main journals which is nice (less friction).

What are your plans for the car? How do you plan on driving and where? Any limitations on available fuel? Budget?

Your 318 probably is backed by a 904 transmission and (possibly) a 7 1/4" rear axle so leave room to upgrade both of those or you may very well leave a trail of busted metal behind you. If you're positive about the aluminum heads, Edelbrock has a good reputation. They should work right out of the box but can be improved (ported, port matched intake and exhaust, etc.) if you need more. You'll want to match the cam to transmission (4-speed or auto's torque converter stall speed) and planned rear gears. I can tell you that you will be very disappointed with the stock gears. There are different qualities of stroker "kits". Some require more or less work to install. Lots of people suggest a forged crank (more $$$) but lots of people get by just fine with a cast one. It depends on how you drive the car and how radical your combination ends up.

We do have a "Proven Combos" section but I believe we're a little light on small blocks.

Troy

[CB Freshness]

Thanks for all the help forums are great and I appreciate the advice. I was planning in Edelbrok heads ported. I have a good amount of local help at home. A few machine shops and a couple of performance shops I know the owners of. I'll let y'all know how everything works out.

[randy73]

I am building my 73 340 and a for me I am going full roller, meaning I am going with Hyd. roller cam, lifters and RR's. If you can get a 69-71 block, I do not know this for a fact, but I have heard they are better than 72-73.

Do you have someone to tune your carbs?

I was going to do a 373, but ended up going a different way, but I would ask Ron (Challenger340). That is who helped me.

[64dartgt]

The whole earlier block vs later 340 block thing is a bit mythological (I have a 1971 340 with a sleeved cylinder).  I would suggest you get any block you do a high dollar build (like a stroker) on sonic tested rather than rely on its date of manufacture because of the potential for core shift.

http://www.moparmusclemagazine.com/techarticles/engine/mopp_1112_engine_block_sonic_test_quick_tech/

[CB Freshness]

Well, that's good. Most people don't have that kind of access. The 340 has smaller main journals which is nice (less friction).

What are your plans for the car? How do you plan on driving and where? Any limitations on available fuel? Budget?

Troy,
My plan is to build a around town car that can smoke the tires whenever just for kicks. The furthest ill be driving is like 30-45 mins from home. It's just a cruiser and a show car.

[cudaken]

CB, for what you are asking for, why not a 440?  I do love 340's but they are more of a high RPM engine, that is there strong point. Plus 340's are rarer than 440s.

If you can score a 340 (seems only thing you real want is a block) for free shoot for a 68 to 71 block and sale it on E Bay. Then check local Craig List for a smoggier 440 block if you want to still use a stroker kit. Or a complete 440 short block if you want to stay no bigger than a 440. 

Yes I am a Big Block fan and for melting the hides, a well built stock 440 will cook them with ease. Throw in the right cam, Eddy Heads, headers and a 6 Pack!

Cuda Ken 

[CB Freshness]

Any suggestions on what size gears I should put in the rear end? I don't really need to go over 80 and I wanna be able to smoke the tires pretty easy

[randy73]

First design the engine and stall converter and gears will themselves out, as cam and other factors will drive these.