Is building a stroked 318 better than a stroked 340/360?

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migsBIG

migsBIG

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So I was planning to put a 440 in my 73’ Duster and decided to sell off all my small block stuff and did so over the weekend. At the same time, I was offered a deal on a torquestorm supercharger for a small block and think it might be a fun little combo for the duster instead of the RB engine I’m building. Now all I have left are a couple early 318 engines. Thinking cheap fun might be the way to go for now, contemplating building a 318 for the little huffer and running it in there.

So my question is, what benifits to stroking a 318 than a 340 or 360? Mind you, I’m just talking short blocks here, nothing to do with heads or intakes, just block wise. Now I know some 340’s came with forged cranks, but I don’t think anything really different between the LA blocks. So I’m asking if there is any difference between blocks strength and is it feasible? I could spend another $600-$1000 for a 340 block, $500+ for 360 or use that money towards the 318.
Like to hear some opinions on this.

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Cheaper block to start with and possibly the ability to still go to a 4.00 bore. Sonic check isle 1!!!
 
Strength wise, your ok with any of the blocks. If you already have the 318, and want to use it, makes sense. If you had either of the other blocks, then yes, you give up bore size using the 318.
 
Oh, save the money on getting another block. IMO, spending money on a 340 block to stroke when you have the 318 blocks in hand is kind of silly unless there is a specific reason you NEED the larger bore.

What is that 340 block cost nower days!

IF the 318 can go to a 4.00 bore size, the cheaper 360 pistons come into play here and a real nice little chunk of change in your pocket stays behind.

There is no argument that cubes rule the day. But just to have fun in a street car that doesn’t run in competition or see the high end of the rpm scale as often as a racing engine does?

4.00 X 4.00 = 402 cubes of fun.
 
With the blocks, bore size is not too much of a concern. 22 inches between a 340 And 318 and they both use the same rods and only have two bolt mains, sounds like a few cu in won’t affect hp. The plus side, if I windowed a 318, its not an expensive block.
 
I have been selling 340 blocks and engines for $800-$2500, buildable cores. I sold my last two because they were 1973 units with cast cranks. I figured if I have to order a crank for the 318, may as well order a stroked one since they are the same as a std crank. Cost wise, building either is the same cost, so using my block, motor mounts save buying another core engine.
 
Back when I did my first stroker, I wanted to do at 318 and found out the pistons for a 318 (Back then) were a couple hundred more than the pistons for the more common 360 and when I talked to the machine shop, they had a 360 block for a 150 they were willing to sell me. And getting the extra cubic inches for less was a no brainer...
 
Since you're pushing the air in, do a mild build 318 and get the combo to work then fix all the errors, then build with a larger engine combo, you will probably save money in the long run.
 
migsBIG said:
I have been selling 340 blocks and engines for $800-$2500, buildable cores. I sold my last two because they were 1973 units with cast cranks. I figured if I have to order a crank for the 318, may as well order a stroked one since they are the same as a std crank. Cost wise, building either is the same cost, so using my block, motor mounts save buying another core engine.
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Selling a ‘73-340 because it has a cast crank is crazy unless you’re looking to consistently make over 600 hp in a racing condition. Since the cast crank has proven itself very well for street AND racing duties save all out efforts, I feel that is a bad move. Sorry.

If the state of the block is of concern because it came with a cast crank, that’s double trouble nuts of about 20lbs. of horse **** in a sandwich baggie.
 
If you can dig up a 360 reasonably I'd start with that, if not a 318 fine especially with a 4" stroke and a blower. 390 vs 408 vs 416.
 
i'll echo what the others have chimed in with. save the dosh and build up the 'teen, the internals will be plenty strong as long as you don't go for gonzo power.

spend the real money on heads. that way any dough you lay out can carry over to another bigger and badder build down the line.
 
A guy I know took an absolute junkyard 360 a few years ago, bone stock everything, threw it in an A Body and bolted up a torqstorm to it( they are made right up the road from me) and without leaning on it as much as he could have, it ran well in the 11’s at the track.
If your goals are fairly modest , I don’t think what you bolt the supercharger up to is gonna matter a ton. It’s gonna pretty much double up the power of a stock slug.
 
To me the point of a 4" stroker is to build displacement don't know why you'd start with less than a 360 block for the slight extra that it would cost especially if you factor in piston cost like J Par said, but saying that a 390 still will work good, just makes going stroker make less sense especially this isn't a low dollar build why cheap out on block. 365 vs 390 vs 408 a 390 is slightly over half (25 cid) of the displacement 43 cid gain between 365 & 408.
 
I would have that teener sonic checked to see if it can be bored to 4.00. Some of the early ones before 1972 I believe, can be done. Then you have a 360 block for all practical purposes right there. Add a stroker crank and your supercharger and have fun.
 
I say build the 318. Terry Brighton racing built a 318 stroker with Trick Flow heads, air gap, Lunati 243/251 VooDoo hydraulic roller cam. Made 535/535. Pretty much equal to 360 strokers give or take a few.
 
only issue would be the 318s thinner weaker main caps,.. sooner or later thats gonna be a problem spot when you get to making big power...but its a easy fix just throw on set of 340 caps or buy new caps and line bore them,...kinda needs to be done when planning big power any ways....DWB
 
how are you going to use / drive the vehicle?
what kind of performance do you need?
 
ir3333 said:
how are you going to use / drive the vehicle?
what kind of performance do you need?
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He was saying street fun and driving it.

@273 The added cost of another engine block or full engine could be saved and rolled over into what he already has. It’s also not just the initial cost but also all the little things that come with it before it gets touched.

The cheaper pistons are a nice little savings if it’s a sub 4.00 bore capable block. I think over all, it depends on the 318 blocks ability to be bored to a 4.00 & the cost, start to finish from not having a 360 block starting with topping off the fuel tank to taking it to the machine shop.

I’ll not argue cubes rule the day or overall cost effectiveness in the end result in terms of power. Sometimes it’s just working with what you have instead of getting more stuff and or spending more money, which may not be in abundance.

Between the two engines, the 318 has more expensive pistons being a sub 4.00 bore size. As mentioned above, weaker main caps that may expose itself under hard conditions.

@migsBIG What is the cylinder head plan?
 
if you want a vehicle that has enough power to be fun to drive without being concerned about racing
the 318 would get it done most economically without stroking. If you are going to race, go bigger and
stroke it. And if you are eventually going sell and move on to another project like most of us do, then
you have to build what other people want. That might not be a 318?
 
If he is using the torqstorm, I would use the cheapest piece laying around. It’s gonna be peppy no matter what it is, and if you hurt it, so what.
 
Best that dead horse boys. Kick it. Give it what it deserves. Kick kick kick!!!

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I don’t understand the mind set of building a small bore block. Bigger the bore means less shrouding of the valves and equates to better air flow. Air flow makes power. Which if you’re building a stoker you’re after power. Also a little math helps justify it as well. If the engine is expected to make 1.x hp per cube do the match on the cubes as well.
 
Thin cylinder walls and thin decks don’t play well with boost. Ask me how I know. Build a solid foundation whichever base you choose to start from. Id rather have thick, strong, round bores than bigger bores. Is a 318 stroker better than……..NO. But that doesn’t mean it’s any worse either.
 
TT5.9mag said:
Thin cylinder walls and thin decks don’t play well with boost. Ask me how I know. Build a solid foundation whichever base you choose to start from. Id rather have thick, strong, round bores than bigger bores. Is a 318 stroker better than……..NO. But that doesn’t mean it’s any worse either.
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Torque storm is hardly a serious supercharger. And if it’s something that’s going to make real boost power a factory Chrysler block shouldn’t even be on the build sheet. IMO
 
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