Low cost 349 stroker

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cudaracer

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Low cost 349 stroker:

Using a +0.030" Silvolite cast pistons for $241, heavy duty MP cast 3.58" stroke 318 crank for $404 and Eagle I-Beam rods for $259 and a good quality rebuild kit that includes all lower bearings, seals, gaskets, etc......I am looking at about $1050 to turn my 318 into a 349 stroker. Balancing is free for me, as I have a friend who owes me a favor. I will probably go internal balance. The above combined with my 308 cast heads (65cc measured) puts me right around 9.7 CR with flat piston about 0.029" in the bore. This setup is about $700 less than the kits out there.

I realize that cast truck 318 piston is the week link, but just how weak is it? I am targeting about 375hp & 400ftlbs if I stick with my comp cam (0.477/0.480"). I have a 904 transmission with 3.23 gears, so I can't imagine ever spinning this past 5K. Knowing all that, can someone chime in with their opinion about the expected life span of that cast piston? Thanks all.

Plan B

I could get a 390 stroker kit for about $1800 balanced, but then my cam & 360 heads are choking it, so a new cam would help quite a bit. So there is that added cost.

Thoughts?

Below is all the hardware so far.


Pistons link: http://www.summitracing.com/parts/uem-1278-030
Rods link: http://www.summitracing.com/parts/esp-6123cp/overview/make/plymouth
Crank link: http://www.summitracing.com/parts/dcc-5007257/overview/make/plymouth
Rebuild kit: http://www.summitracing.com/parts/fem-205717-00/overview/make/dodge
 
My question is why all the trouble for a cast crank with the same stroke as a 360? You could probably find a rebuildable 360 for less than the crank you are looking at.
 
The heads on a 390 low performance build are not going to choke it so badly that it'll perform like a bag of crap. Your limited rpm is key.
 
MTmopars said:
My question is why all the trouble for a cast crank with the same stroke as a 360? You could probably find a rebuildable 360 for less than the crank you are looking at.
Click to expand...

Ditto. Unless he is meeting a class rule?????
 
MTmopars said:
My question is why all the trouble for a cast crank with the same stroke as a 360? You could probably find a rebuildable 360 for less than the crank you are looking at.
Click to expand...


I would need a complete short block for 360, even oil pan and motor mounts.
And then I would need to machine it.

Kind of like keeping original 318 in place as well.
 
Your friend better own you one HELL of a favor. Wait till you see how high Mallory metal is now.
 
If you can limit the rev's then cast will live. Keep a good tune & watch out for detonation.
 
The pistons will hit the crank at BDC, and you will need to mill the bottoms of the pistons to make room. I would balance it like a 360, external. Its cheap and works just fine. Like rusty said, mallory is $$$$ and you will need about 3-4 slugs of it!
 
I know they don't like a 300 shot of NOS for long haha.but other then that they go for ever I would think even at 5500 rpms....Artie
 
Cast pistons can and do live beyond 5500 rpms...the silvolites are hyperuetectic anyway...seen it done it...if properly set up, they can and do live into 6000+ for beyond 100k miles. The most sustained hits of nitrous I've seen used on them is 150-180...by sustained I mean 3-5 runs in a night, for about half a season before the rings finally just gave up.

But, like Mike said, they'll require machine work to fit within the confines of the crank counterweights.
 
These kinds of builds just seem like a case of false economics. JMO
Just pick up a 360 and build that while the 318 is still pluggin along.

hyper pistons and moly rings $159
http://www.ebay.com/itm/Dodge-Mopar...Parts_Accessories&hash=item485b9f0a03&vxp=mtr

oil pan $35
http://www.ebay.com/itm/RAW-Upnaint...Parts_Accessories&hash=item3f29bead1b&vxp=mtr

I got an externally balanced 360 stock rods stock crank turning 6800ish using these same Ebay pieces that runs low 11s. Probably cheaper and easier to build than that 318 stroker deal. Likely more durable too.
 
I've taken cast pistons to 7000 and a little beyond (limiter chip was 7400) for a season of weekly drag racing. I put it together to see how hard I could beat something before it broke; it didn't. I posted it in eather 318 builds, or 12 second combo's.

You stated they are a truck spec piston, probably heaver than a car piston; meant to take the abuse of detonation and running hot. They are probably not as weak as you think.

I'm surprised that they will still be down in the hole even with a 3.58 stroke. I say go for it. Nobody needs to know it's a stroked out "teen", just say it's a plain Jane "teen" that runs good.
 
The ones he's talking about are a 1.658" comp height...they're like 0.160" in the hole as a 318 (assuming 9.6" deck height)...add 1/2 the stroke of a 360, and you increase .135" throw...still in the hole-crazy.
 
skrews said:
These kinds of builds just seem like a case of false economics. JMO
Just pick up a 360 and build that while the 318 is still pluggin along.

hyper pistons and moly rings $159
http://www.ebay.com/itm/Dodge-Mopar...Parts_Accessories&hash=item485b9f0a03&vxp=mtr

oil pan $35
http://www.ebay.com/itm/RAW-Upnaint...Parts_Accessories&hash=item3f29bead1b&vxp=mtr

I got an externally balanced 360 stock rods stock crank turning 6800ish using these same Ebay pieces that runs low 11s. Probably cheaper and easier to build than that 318 stroker deal. Likely more durable too.
Click to expand...


what pick up is used with that pan? thats a steal at the price if its a decent pan..
 
cudaracer said:
Low cost 349 stroker:

Using a +0.030" Silvolite cast pistons for $241, heavy duty MP cast 3.58" stroke 318 crank for $404 and Eagle I-Beam rods for $259 and a good quality rebuild kit that includes all lower bearings, seals, gaskets, etc......I am looking at about $1050 to turn my 318 into a 349 stroker. Balancing is free for me, as I have a friend who owes me a favor. I will probably go internal balance. The above combined with my 308 cast heads (65cc measured) puts me right around 9.7 CR with flat piston about 0.029" in the bore. This setup is about $700 less than the kits out there.

I realize that cast truck 318 piston is the week link, but just how weak is it? I am targeting about 375hp & 400ftlbs if I stick with my comp cam (0.477/0.480"). I have a 904 transmission with 3.23 gears, so I can't imagine ever spinning this past 5K. Knowing all that, can someone chime in with their opinion about the expected life span of that cast piston? Thanks all.

Plan B

I could get a 390 stroker kit for about $1800 balanced, but then my cam & 360 heads are choking it, so a new cam would help quite a bit. So there is that added cost.

Thoughts?

Below is all the hardware so far.


Pistons link: http://www.summitracing.com/parts/uem-1278-030
Rods link: http://www.summitracing.com/parts/esp-6123cp/overview/make/plymouth
Crank link: http://www.summitracing.com/parts/dcc-5007257/overview/make/plymouth
Rebuild kit: http://www.summitracing.com/parts/fem-205717-00/overview/make/dodge
Click to expand...


everybody is asking why, I say WHY NOT!!!! I like it.:glasses7:
 
Do whatever makes you happy... But seems like a lot of work,calling in favors, worrying about machining etc... For what 25 ci when all is said and done. You can do a 408, 390, 360 and say its a 318 nobody's going to check and most guys know about stroker kits, and know a 318 can be punched out to 400...
 
Thanks to all!!
I love the advice and enthusiasm on this site.

And I completely understand the 360 questions/remarks, and I have done the math, but what I am doing is probably cheaper, because I already have the block, don't need oil pans & motor mounts....but more importantly, it allows me uniqueness while keeping the orginal block in my numbers matching 72 cuda. That clinches it for me.

Thinking about it more, I doubt I need much durability, no more than the average cruiser who might make it to the drag strip once every 5 years. And how do you rev a 3 speed automatic very high in the first place? I don't think it has ever been north of 5K, ever.

So to recap,
I forgot about piston to counterweight clearance, but not a problem, I can have that done at work along with small valve reliefs. I like that this rotating assembly will weigh a little less than forged 360 pistons, so faster rev's are probable. I am also fine with external balancing, based on my planned RPM range. The crank is HD with filet radii too.

A few more questions however:

1. Are those Eagle rods overkill with cast pistons, where I could just ARP my current cast 318 rods?
2. Is there tooling to help dimple my piston tops easier?

Thanks
 
EL5DEMON340 said:
Do whatever makes you happy... But seems like a lot of work,calling in favors, worrying about machining etc... For what 25 ci when all is said and done. You can do a 408, 390, 360 and say its a 318 nobody's going to check and most guys know about stroker kits, and know a 318 can be punched out to 400...
Click to expand...

Well, my original plan was to just zero out my teen with new pistons, as I have already done the top end. But then I thought, more torque is needed, and so the 360 crank gets me there. Not so much about cubes, as it is a longer stroke arm. Makes sense, right? And another bonus on those silvolites, is they are completely flat, but will only have slight dimples if needed once I do my P2V check.
 
Nice to have the eagle rods but since your not reving high the 318's should be ok, maybe better to look for a set of 340 rods
 
I prefer stock rods,ARP bolts. Isky ,rents a tool ,to fix the "dimple"s. Rent it,with a deposit, use it. Get refunded minus the rental fee. My take. Easier ways to thing's,yours sounds feasible. Poor balance job guy.....
 
if you can put it together "low cost" that would be an excellent bore / stroke combination.
It has worked well for the General for years being the preferred combination for the companies flagship (Corvette) 3.90 bore x 3.62 stroke!
 
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