Should I Stroke my 340?

[1 Wild R/T]

If you stroke it to much you'll go blind.....  Oh, wait wrong stroke.... 

[bennydodge]

If you stroke it to much you'll go blind.....  Oh, wait wrong stroke.... 

So I've been told...at this point I should be blind as bat lol...

[cudaragtop]

Crane
Camshaft: SR246/362-2S-8IG , .543/.561 L/S: 104 Int. C/L: 108           

What are the cam specs?

I'm at 9.7:1 measured compression same heads.

On California 91 octane 9.7:1 is max with my setup. At 800 ft altitude, 90+ degree weather. With quench, sharp edges smoothed in chamber, chamber bore matched to block bore.

I'm pretty sure my cam is smaller; XE274 solid Comp.

[kape1]

I love the torque curve on my 340 stroker 

[Chryco Psycho]

Me too 

[tparker]

Cool. Thanks for the tips. I already have the 340 and not sure about searching for a 360, which will just add even more to the build. I'm thinking of stroking it (the Engine, just to be clear ). Unfortunately I have to do the complete build in steps. I'm gonna leave the current heads on for the time being. Maybe swap them out next year or so. I need to get it running this year, with parts I have.

[Chryco Psycho]

A core 360 should be almost free

[autoxcuda]

Cool. Thanks for the tips. I already have the 340 and not sure about searching for a 360, which will just add even more to the build. I'm thinking of stroking it (the Engine, just to be clear ). Unfortunately I have to do the complete build in steps. I'm gonna leave the current heads on for the time being. Maybe swap them out next year or so. I need to get it running this year, with parts I have.

Remember stock open chamber iron heads have 68-72cc chambers. Old 40 yr heads could be cut down. No predicting those.

Typical aftermarket head is 64-65 cc. They haven't been cut. Castings more consistent. Should be able to find repetitive numbers others have measured before buying

Switching heads later is going to be a major compression change. Don't believe that old tale about aluminum heads handling 1 full point of compression

You can check the cc's of your current heads yourself. Jegs and Summit have kits under $30.

Switching between a 72cc head and a 64cc will mean in setup will have too much or too little compression... Or both.

Lock down a game plan now.

[gzig5]

A core 360 should be almost free

Agree.  I paid $150 for a very clean 77 360 block and that was with no leg work.  Now I've got my eyes out for a transitional 360 block, 88-92.  Factory hydraulic roller lifter but still with the LA heads that oil through the block and rocker shafts.

360s aren't as numerous as the 318 blocks.  Is there truth to the story I was told about boring a 318 Magnum block to 360 dimensions being an option?  It's only going from 3.91 to 4.00 to get to stock bore and then another .030 would give you the magical 408 with a 4" crank.  I think most of the stroker kits have 4.030" pistons.

[Chryco Psycho]

It could be possible to bore a 318 that far but you would want to sonic check the walls or sleeve the block taking it .090 over , of course the 318 uses a smaller crank journal also so you would need a 340 based crank

[gzig5]

It could be possible to bore a 318 that far but you would want to sonic check the walls or sleeve the block taking it .090 over , of course the 318 uses a smaller crank journal also so you would need a 340 based crank

Right.  Wasn't sure if they used the same core sizes for the castings and just took the 360 bore out an additional .010".  If so it would seem to follow that both blocks could be bored to same dimension.  But you are right, a sonic check is advisable before sinking that cost into the block.

[tparker]

@autoxcuda yeah, your right on changing the heads later. argh. I'm trying to do what I can now without breaking the bank. I gotta decide if I really want to do the heads or not.

[autoxcuda]

@autoxcuda yeah, your right on changing the heads later. argh. I'm trying to do what I can now without breaking the bank. I gotta decide if I really want to do the heads or not.

Yea it's a bummer.

Don't know if you could mill stock heads down to 64 cc's

If so, I'd think you'd have to check pushrod length. And you might have to mill intake.

[bluemp301]

Personally I'd spend the coin on the top of the motor and leave the bottom alone.

I don't know enough about mopar engines yet (currently learning) however I can share my ford knowledge.

A current trend in the foxbody community is taking stock 302 engines (many with 100k+ miles), and putting 190cc trickflow heads matched with a specific carb or efi intake and a custom cam and making 350-375+rwhp and rwtq on pump gas.
I should also mention these aren't max effort builds, keeping things around 6500 max rpms with excellent drivability.

Imagine adding 38 cubes to something like that.

[chargerdon]

"Don't know if you could mill stock heads down to 64 cc's"   

I'm no expert, but, i had a built 360 with Edlebrock RPM Air Gap intake manifold.  Block thru a rod right thru it.    Heads are the 915 J heads, that  had previously been decked and prepped for dual springs. 

I bought a 72 360 for $100, and built a 408 stroker with it (SCAT brand crank and rods,  Icon dished pistons).   My heads from old engine are the 915 J heads, that had been machined before.   I had the machinist CC them for me and they are right at 64 CC...   So, they must have been cut as machinist said stock is more like 70-72 cc.  Regarding the intake, The Edlebrock RPM AIR GAP bolted right on with no problems.   Maybe it had been cut to go onto the heads previously, or maybe not...but they bolted right on. 

Yes, with new block and after having both the block and heads decked to make sure they are true, i had to buy 7.5 pushrods as the previous 7.6 was giving too much prelift but there was too much prelift in previous block as well.  but their cheap...  After decking the pistons sit .004 below deck, and pistons are dished -20.5 cc.   With that 64 cc heads and 408 cubes, using Felpro .051 thick gasket, compression figures to be 9.7.   Running 93 octane gas, with static ignition timing set to 18 btdc, and limiter in mopar electronic ignition distributor set to max 16 mechanical advance, im also running 10 degree vacuum advance on full vacuum side, so at idle its around 30 degrees advanced and total advance under load is right around 34 degrees and i do not hear any ping...lol...exhaust is so loud how could I ...lol...     

hope this helps..