To stroke or not to stroke... That is the question.

[BDL]

Alright... I've never built a stroked poly 318. Who has? Was it worth stroking or should I stick with the stock crank?

I'm thinking I'll have it bored it out 0.090 over to use a 4" piston and use one of the piston/connecting rod/(crank) combos from chryslerpower.com. If my crank is okay, then I'll be tempted to save around $400 to stick with the stock crank over the stroker... But should I?

If I don't stroke it, the engine will be 333 C.I. But if I stroke it, the engine will be a nice little 402 and could have some huge power potential.

Are there drawbacks to stroking a poly 318?

 

[Kern Dog]

To stroke or not? What does your Pastor think of this?

 

[cryplydog]

Just go get a good junkyard 360 4bbl and do a rebuild and save the poly if its a numbers thing. Or go BB! Ain't that bigga deal. good luck. Most pollys just want a cracker.

 

[5.7 hemi]

Stroke that boat anchor!!

 

[Kern Dog]

You can make decent power with a stroked Poly engine.
Being different can be fun.

 

[moparwacko]

"Rather be Cummin than Strokin"

Ooops, wrong forum.
Go ahead and bore and stroke that puppy.
Dare to be different

 

[PRND21]

There is no replacement for displacement, as the old saying goes. Cost/benefit ratio needs to be determined.

 

[66Satellite47]

Just my opinion but keep the poly motor for future value and slap a BB in it.

 

[dieseldazzle]

Poly in the corner of the garage.

Mild cheap 440 in the car.

 

[moper]

You certainly can stroke the Poly. But it will cost a lot more than building a more common stroker or a stock displacement engine. If it was me and I wanted the Poly look, I'd rebuild it with the stock stroke, but with good pistons, some minor head work, and a cool induction. Then it's different without breaking the bank.

 

[BDL]

Here are the costs that I've seen so far... Tell me where I'm going wrong or what I'm missing, please!

Machining on the engine block and heads (done locally by a guy who knows Mopars) - Includes the basics: Hot tank; magnaflux; new valve seats; new springs; new valve guide seals; new bearings; clean and polish the crank (if I choose to use the stock crank); and bore the engine. - $1800

Engine piston/connecting rods/crank options:

Option A - (333 C.I. (0.090" over), 9.00:1 CR- est. 340HP):
New CP/SpeedPro Pistons, New Connecting Rods (Using My Crank)
www.chryslerpower.com/webstore/Poly/ECONO-330-333-PKG - $695

Option B - (402 C.I. (0.090" over), 9.75:1 CR - est. 400+HP):
New Pistons, New Connecting Rods, New Crank
www.chryslerpower.com/webstore/Poly/Streetfighter-Poly-Stroker-Kit - $1098
​

New 4-barrell Intake, Intake Gaskets, Bolts & Rebuild Gasket Kit
www.chryslerpower.com/webstore/Poly/Poly-SS-X-Manifold - $882

New Cam (264/.450"([email protected]”)2000 to 6000) and Lifters
www.chryslerpower.com/webstore/Poly/Camshaft - $404


New EZ-EFI® Self Tuning Fuel Injection System Master Kit w/ Inline Fuel Pump Kit
http://www.fuelairspark.com/fas/ez-...system-master-kit-w-inline-fuel-pump-kithtml/ - $1199.99


All told (realizing that I'll probably need new pushrods and some other incidentals), here are the totals:

333 C.I. Poly good for an estimated 340HP: $4680.99

402 C.I. Poly good for an estimated 400HP: $5083.99

 

[PurpleBeeper]

I know NOTHING about poly motors.... but can they go .090" oversized on the pistons? Without sleaving the block?

If it's numbers matching (especially), I'd have to go with some of the other guys....save the poly 318 and build a larger, more common motor.

 

[Cranky]

I ASSume this is for your 66 Charger....? Those are kinda heavy and around 4000 lbs, right? Heavy cars benefit from lots of torque....

 

[5.7 hemi]

Don't use the FAST 1.0, get a Holley or FITECH.

 

[BDL]

I know NOTHING about poly motors.... but can they go .090" oversized on the pistons? Without sleaving the block?

It's hard to believe, but guys have been doing it with good success. Check this out (from a HotRod article back in '01 http://www.hotrod.com/articles/mopp-0110-how-to-give-a-318-poly-engine-more-power/ ) :

...In fact, we had heard that hot-rodders of yore would bore these old Polys to .090 or more for increased displacement, meaning the stock 318 Poly bore size of 3.91 moved up to an even 4.0 size! Coupled with the brand-new Mopar Performance 4-inch stroker crank for the LA 318/340 motor (PN P5007256), which is interchangeable with the Poly 318, this combo would thus yield a 4-inch bore by 4-inch stroke for a monsterous 402ci Poly motor.

Can the block take the huge overbore? After we sonic-tested the block, it proved this could be accomplished with cylinder wall to spare. All machine work, engine assembly, and dyno-testing was meticulously performed by Ed Hale High Performance Engines in Lakeside, California, under the watchful eyes of shop foreman Gary Camp and me. The added support of head-flow testing and port work was assisted by Dr. John of Total Performance in Santee, California.

Workin’ It
The block was bored and honed using deck plates to a .090 overbore, then fully decked to level all surfaces. ...
​

 

[BDL]

I ASSume this is for your 66 Charger....? Those are kinda heavy and around 4000 lbs, right? Heavy cars benefit from lots of torque....

Yessir... It's for the '66. Stroker would definitely give me the torque I want

 

[BDL]

Don't use the FAST 1.0, get a Holley or FITECH.

And this is something I NEED to know... Which FI setup is best to go with? I have a great friend who's high up in Holley, but he won't give me any deals I complained to him about their website today (in fact) and he said his guys are aware of the issues I complained about and are working on a solution. I really want to know what exactly I need to buy from Holley in order to get an EFI setup to work on my classic Mopar but their site isn't helping. Have you added FI? What's needed? What are the pros and cons of the different "kits" (realizing that there really aren't any specific kits for the poly) out there?

 

[Cranky]

Yessir... It's for the '66. Stroker would definitely give me the torque I want

A small engine that's stroked is still a small displacement engine. It'll have more torque but not that much more. Look at a /6 with it's long stroke. It'll move the heavy stuff but not all that fast....to make more power an engine needs to generate more torque, operate at higher rpm, or both. You can make a small displacement engine produce more power by spinning it faster but you will need more rear end gearing, a loose converter etc to accomplish that. I've heard of people taking the poly teen out to 4" and stroking them too but before you bore it that much, sonic test it first but if it were mine, with a car that heavy, I'd be looking at a big block. Even a stock stroke 440 will produce 440 hp with ease and the torque will be up there pretty close if not more but if you want the look of the poly and have the spare cash, got for it....

 

[5.7 hemi]

Get a a Holley Terminator or Sniper. They work! Plus you can upgrade for free (V4) and then you can have anyone with FI tuning experience tune it. The learning part is great, hell, I fired a new engine with the Terminator and it runs great and my buddy did the V4 upgrade and his 340 runs like a striped ape.

You will need an electric pump, filters, hose, regulator and miscellaneous stuff to run efi.

Check out both systems, either one will work just fine.

 

[Cranky]

Get a a Holley Terminator or Sniper. They work! Plus you can upgrade for free (V4) and then you can have anyone with FI tuning experience tune it. The learning part is great, hell, I fired a new engine with the Terminator and it runs great and my buddy did the V4 upgrade and his 340 runs like a striped ape.

You will need an electric pump, filters, hose, regulator and miscellaneous stuff to run efi.

Check out both systems, either one will work just fine.

What's his 340 in and has he ever made any passes at the track?