Chrysler LA / NASCAR 355 cu. in. crank shaft

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mark_mopar

mark_mopar

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I recently purchased a lot of Chrysler parts from a guy who claimed his grandpa was a NASCAR racer. Looks like a have a 355 cu. in. crankshaft for a small block LA. I have another crank that looks just like it that came in the lot i purchased, but I can not confirm its specifications yet.

What do I do with this crank? I really don't have a use for it. What's it worth? Who can use it?

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I think it all depends on what connecting rods and what pistons would make a build happen. If it requires a special length rod, or a custom piston for example, it won't be as attractive as say something that uses affordable off the shelf pieces.
 
If you use a 318 compression around 1.740, you can get real close to zero deck with a stock 6.123 rod. Also it's going to depend on whether it's for 340 or 360 main journal size.
 
That would be fun in a 340, piston cost may be a drawback though.
 
You may want to measure your main and rod sizes just to confirm you don’t have anything oddball. Some of the later NASCAR custom cranks were built with smaller main (Crower ground some with 302 Ford sized mains) and Chevy or Honda sized rod bearings.
 
Mopar had custom pistons for those cranks back in the day. If somebody has some good, old 340 pistons, one could take some careful measurements to see if the tops are thick enough to mill down. An unmilled block would help. It would be a good way to save some weight on some of the old TRW or Speed Pros. Gotta check counterweight clearance to the piston bottoms too. A forged low compression 340 piston might be a good candidate, preferably with valve notches. Along the same lines as the original "Hoover's Mover" (360 with modified OEM low compression 340 pistons), but with less stroke and less milling to worry about.

Years ago I had a set of the 3.454" stroke 355 pistons and had them milled to work with a 3.58" 360 crank! I might still have them buried somewhere.

I'm pretty sure they were only available with 318/340 mains and an 8 bolt flange.

355 V8: The Mopar LA Racing V8 Engine
 
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You need to find what rod journal its ground for. As mentioned above, it more than likely has Chevy journals but could also have Honda journals which was common in the last 10 to 15 years if the crank is that new. Be aware of its Honda journal, the width of the journal will be narrow also like the Honda making them more custom priced.
 
That crankshaft was designed by Mopar to help the 340 stay under the 360 cubic inch class in racing. I believe it was used in sprint cars and other class racing.
 
That crank is a drop in 318 mains stroker candidate with stock 318 pistons and rods. It should have 318 mains as that is what the 340 had and that is what the sub 366 cid NASCAR motor was based on with the bigger 4.04 bore than the 360 but without the >366 CID stroke combination. That crank on a .080 in the hole 318 will get your piston up +.072 to get you close to zero deck (~.008) clearance. Sell it to a 318 builder if your not going to use it with the special 355 pistons or special rods, etc.
 
mark_mopar said:
I recently purchased a lot of Chrysler parts from a guy who claimed his grandpa was a NASCAR racer. Looks like a have a 355 cu. in. crankshaft for a small block LA. I have another crank that looks just like it that came in the lot i purchased, but I can not confirm its specifications yet.

What do I do with this crank? I really don't have a use for it. What's it worth? Who can use it?

View attachment 1715827441

View attachment 1715827442
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Just curious but what else did you get ?
 
pishta said:
That crank is a drop in 318 mains stroker candidate with stock 318 pistons and rods. It should have 318 mains as that is what the 340 had and that is what the sub 366 cid NASCAR motor was based on with the bigger 4.04 bore than the 360 but without the >366 CID stroke combination. That crank on a .080 in the hole 318 will get your piston up +.072 to get you close to zero deck (~.008) clearance. Sell it to a 318 builder if your not going to use it with the special 355 pistons or special rods, etc.
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Any idea how much he should price it for?
 
Could they be left overs from the 90's when Dodge ran in the IROC? Those engines were 355 ci and I think they were based on the 318 block. Get out the micrometer and check. They may be a great start for a killer street engine.
 
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What's a 391 stroker 318 crank cost? Demand is what it is unless you can find a 355 builder. This is a cheap alternative to make a tiny 318/331 stroker without custom pistons. In a 340 its a...354!
 
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pishta said:
That crank is a drop in 318 mains stroker candidate with stock 318 pistons and rods. It should have 318 mains as that is what the 340 had and that is what the sub 366 cid NASCAR motor was based on with the bigger 4.04 bore than the 360 but without the >366 CID stroke combination. That crank on a .080 in the hole 318 will get your piston up +.072 to get you close to zero deck (~.008) clearance. Sell it to a 318 builder if your not going to use it with the special 355 pistons or special rods, etc.
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So you're saying I can use this crank with the factory rods and factory pistons? Basically replace my current crank with this one?
 
try it, you may find the 318 pistons are at near zero deck with the new stroke. Only need a balance job after that (maybe)
 
mbaird said:
Just curious but what else did you get ?
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Couple three speeds, couple small block manual bellhousings, a modified oil pan, couple new crower and racer brown cams, factory 340 4bbl cast intake, 2 barrel intake, lots of gaskets including Direct Connection brand W2 / oval port intake gaskets. a pair of X heads, a single J head. couple cast small block cranks. maybe a few other things.
 
Garrett Ellison said:
You may want to measure your main and rod sizes just to confirm you don’t have anything oddball. Some of the later NASCAR custom cranks were built with smaller main (Crower ground some with 302 Ford sized mains) and Chevy or Honda sized rod bearings.
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Don't forget the Chevy rear flange/pilot size/flywheel register. I have a 318/340 main shaft with 283 Chevy rod pins, 3.25" stroke and a Chevy rear flange!
 
Bighead440 said:
Don't forget the Chevy rear flange/pilot size/flywheel register. I have a 318/340 main shaft with 283 Chevy rod pins, 3.25" stroke and a Chevy rear flange!
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Bizarre! This 3.454 stroke crank I have has a 6 bolt rear flange. People kept asking if it was 8. What does that matter?
 
mark_mopar said:
Couple three speeds, couple small block manual bellhousings, a modified oil pan, couple new crower and racer brown cams, factory 340 4bbl cast intake, 2 barrel intake, lots of gaskets including Direct Connection brand W2 / oval port intake gaskets. a pair of X heads, a single J head. couple cast small block cranks. maybe a few other things.
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Some KB or Icon pistons in a 318 with that crank and the X heads could make an engine very similar to a 340, performance wise.
 
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