Stroker Pistons, 318 3.58 stroke?

[71beater]

So, I know there's 3.58" stroke cranks out there, and I've read of 3.79" stroke cranks... Where would one find pistons for such things?
I like the idea of a bigger 318 but feel the now common 4" is a bit much for a mostly street engine, given all the ??? of life span with the 4" arm and associated cylinder wear from the greater thrust loads.
Also, though I've read of the 3.79" cranks, I don't see any out there. Was that something out there before the current wave of 4" cranks?
Any input appreciated (besides the obvious, just get a 360)...
(318s are still usually close to free, and hey I actually like'em, plus there's always the "what's in that?", oh just a 318...)

 

[rumblefish360]

Pistons for the 3.58, & the 3.79 for the small bore 318 are all custom. AKA Expensive. Though the 4 inch stroke slugs are pricey, they are on the shelf.
Life span may be shorter, but, it isn't like it will last only 5 years and start chugging down oil and such. A lot is how you drive it and how much stress it is under. (Stress = HP torque loads)

The 3.79 used to be the biggest stroker crank you could get. MP had a large verity of stroker cranks.

Build the teen with the 4 inch arm and enjoy. At .030 overbore, with 390 cubes, there's nothing to be worries about.
.060 over = 3.97 bore to equal 396 cubes, if you able through sonic checking and dare go to a 4.0 bore, it now becomes a 402. But that is a lot of overbore for a teen. It is possible.

 

[oldkimmer]

,...............Yes, it is possible to go to a 4 in bore on a 318.........i've bored a couple to 4.04 which is stock 340 size......get it sonic checked.....kim........

 

[Mad Dart]

,...............Yes, it is possible to go to a 4 in bore on a 318.........i've bored a couple to 4.04 which is stock 340 size......get it sonic checked.....kim........

I also have bored a 318 to 4.0 using a 4.0 crank.....402CI. Sonic Check for sure.

 

[replicaracer43]

Yeah, I dont see the logic in building a 318 with a 3:58 stroke, you would have an underbored 360, basically.. The cost of the pistons would more than pay for a 360 block.. Remember too, that the larger bore size allows the head to flow more air when its on the engine...

 

[brokensaw]

i rebuilt a 318 a few years ago that had crappy cast jobber pistons that were.120 recessed ithink that could have worked with the 3.58 crank

 

[fishy68]

I think the tale of 4" stroke engines only lasting a very short time is blown out of proportion. After all numerous engines had a 4" or longer stroke and lasted a long life. The Chevy 454 is a 4" stroke engine and has rod's that are nearly the same length as SB Mopars and they lasted ok. Not the greatest lasting engine like a 318 but I've seen them go 125,000 miles before using oil. Engine life depends on quite a few things such as final drive ratio (gear ratio/tire height), converter stall speed, oil change intervals, the power level it develops, the weight of the vehicle it's lugging around and how you drive it... JMHO

 

[Badart]

I think the tale of 4" stroke engines only lasting a very short time is blown out of proportion. After all numerous engines had a 4" or longer stroke and lasted a long life. The Chevy 454 is a 4" stroke engine and has rod's that are nearly the same length as SB Mopars and they lasted ok. Not the greatest lasting engine like a 318 but I've seen them go 125,000 miles before using oil. Engine life depends on quite a few things such as final drive ratio (gear ratio/tire height), converter stall speed, oil change intervals, the power level it develops, the weight of the vehicle it's lugging around and how you drive it... JMHO

Good points Fishy. I think most guys that build a stroker motor don't intend to baby the car.

 

[Badart]

So, I know there's 3.58" stroke cranks out there, and I've read of 3.79" stroke cranks... Where would one find pistons for such things?
I like the idea of a bigger 318 but feel the now common 4" is a bit much for a mostly street engine, given all the ??? of life span with the 4" arm and associated cylinder wear from the greater thrust loads.
Also, though I've read of the 3.79" cranks, I don't see any out there. Was that something out there before the current wave of 4" cranks?
Any input appreciated (besides the obvious, just get a 360)...
(318s are still usually close to free, and hey I actually like'em, plus there's always the "what's in that?", oh just a 318...)

I am actually collecting the parts to build a 318 with the 360 3.58" stroke. I have everything except the MP crank and I will be buying that soon. This will actually be a budget build. Don't laugh. The biggest expense will be the crank and balancing. I bought the pistons from a great Fabo member who just used them for mock up. Everything else I have either bought used or on the cheap.

Why am I building a 349? Because I can and I want to be different.

 

[RAMM]

I am actually collecting the parts to build a 318 with the 360 3.58" stroke. I have everything except the MP crank and I will be buying that soon. This will actually be a budget build. Don't laugh. The biggest expense will be the crank and balancing. I bought the pistons from a great Fabo member who just used them for mock up. Everything else I have either bought used or on the cheap.

Why am I building a 349? Because I can and I want to be different.

I'm building one of these as well. I'm going to try and keep it super cheap so I can offer it to all the guys that are stuck with their 318 blocks. Personally I think it will be an easy 400-440 hp with great street manners. J.Rob

 

[mopardude318]

i like the 3.79 stroker engines out of a 318...i wanna build one soon.. next engine for sure...

 

[dartjack]

Do you have a part # and/or pic of the pistons? Got building one on my mind also. My block was -.107 with stock mopar pistons. Would be about .030 out with rebuilder pistons with valve notches. Comp ratio and valve clearance has me scratching my head. Planning on using 340/360 heads with open chambers so the piston would fit if the valves don't get too cozy with them.