Author Topic: Stroker Basics  (Read 1907 times)

Offline ChallengerHK

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Stroker Basics
« on: August 17, 2007 - 01:26:18 PM »
This is all for the future, but I've been looking at good ways to build a small block and after looking at turbos and blowers I'm starting to look at stroker motors, which seems to have a lot of advantages and no disadvantages (such as, say, turbo lag). My gut instinct is that there have to be some disadvantages, so what are they? Can anybody recommend a good reading source for info?

On a similar note, if I go this route, should I use my '69 X-head 340, or should I find somebody who really wants that motor and is willing to pay through the nose for it and get a salvage yard 360 to build? It seems like the 340 is potentially worth more to a collector/restorer.



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Offline MEK-Dangerfield

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Re: Stroker Basics
« Reply #1 on: August 17, 2007 - 02:42:19 PM »
I can't help with the first part, other than to say I hope you won't be connecting it to a 904 tranny.  :22yikes:

I like the way you think though. Sell the valuable 340, and use that money to build up a 360 that would come faaar cheaper. Just my 2 pennies here.  :2cents:


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Offline ChallengerHK

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Re: Stroker Basics
« Reply #2 on: August 17, 2007 - 03:41:02 PM »
I can't help with the first part, other than to say I hope you won't be connecting it to a 904 tranny.  :22yikes:


No, but that's a good warning  :bigsmile:.  Also for the future I scored a 518 a couple of months back.  It's a non-lock-up, so even if I build past 500 horsepower I think I'll be OK.


"She'll make point five past light speed. She may not look like much, but she's got it where it counts, and I've made a lot of special modifications myself."

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Offline ntstlgl1970

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Re: Stroker Basics
« Reply #3 on: August 17, 2007 - 04:27:53 PM »
"no disadvantages (such as, say, turbo lag)".

In a V8 car, turbo lag can be a good thing (as in more controllable). There is a ton of turbo info here: (don't pay attention to the fact it is a mustang board) on the mopar page

http://www.theturboforums.com/smf/index.php?board=21.0

http://www.theturboforums.com/smf/index.php?topic=23208.0
70 Cuda, 7.0L Gen-III Hemi, Viper T56 w/9310 gearset, 3.91's, Megasquirt MS3x v3.57, Innovate wideband, Firm Feel upper arms, torsion bars, springs and strut rods, QA1 DA shocks. I did everything on this car except the fancy paint stuff and I drive it...and I can't seem to stop messing with it....

Offline moper

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Re: Stroker Basics
« Reply #4 on: August 17, 2007 - 04:33:40 PM »
The down side is, there are certain thinkg you should equip it with, or have done to it. So between the added parts, and the slightly more cost of machining work, they end up about 10% more expensive. The up sides are:  ease of interchange. You have everything it needs..brackets, mounts, etc; Power curves that best match a street driven car; Manners that make it much more suitable for a street car; Visually it is indestinguishable from the base enigne you start with. In terms of value, the 360 based egnines are the cheapest. In terms of max power possible, the 340 would ge the nod from me. If you have a good running '69 340, even un-rebuilt, it has a bunch of value. If you are truely looking for a fairly simple build, find a 360 core from a mid 70s truck. If you are looking for cruiser, and you can abide by the rpm limits (under 5500), there are more piston options in cheaper types, and factory rods can be used, cutting the cost a bit. The iron heads will support it cdecently to about 5500 anyway. Beyond that, you need to either buy some porting or buy better heads. Also, you will need to buy a bigger carburetor to fed it. Bigger than you might normally budget for. You could sell the complete runnign 360 for about 1/4-1/3 the cost of a nicely built 5500 red line 408.

Offline The Cuda Guy

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Re: Stroker Basics
« Reply #5 on: August 17, 2007 - 04:43:17 PM »
Go with the 360 block, port and polish the heads and intake and stroke it!  The only down side I have read is that you might have to go with an external oil pick up depending on the stroke.  Also the machine work depending on how large the stroke.

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Offline HP2

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Re: Stroker Basics
« Reply #6 on: August 17, 2007 - 05:47:56 PM »
...or better yet use a R3 block and a custom crank you can stroke and poke it up to around 450 inches.

Offline Morris'_Mopars

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Re: Stroker Basics
« Reply #7 on: August 17, 2007 - 06:09:29 PM »
I would sell the 340 and heads and put that money towards the stroker. I only say this because I just purchased a 69 340 w/X heads for my 69 Dart. I have been looking for a complete 69 engine for a while now. Someone will pay good money for the block and heads. I have seen the X-heads ready to go sell for close to $1000.00. :2cents:
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Offline go-fish

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Re: Stroker Basics
« Reply #8 on: August 17, 2007 - 06:28:21 PM »
Before I make my comment let me tell you why you should take my advice, I am not trying to come off as an LA block expert or a know-it-all, it's just that I have gone through all of this. I have been piecing a centrifugally supercharged 360 derived 408" stroker. I started with a book as should you. The book is "How to Build Big-Inch Mopar Small Blocks" - by Steve Szilagyi. http://www.amazon.com/Build-Big-Inch-Mopar-Small-Blocks-Design/dp/1932494065
Get it before you do anything. It is the best reading material for the subject.

Personally I would stick with what you have and if you wanted to go with a 360 it is best to get a 1971-1975 block as they are the first ones and had the high nickle content in the iron like all 340's did. You will be able to build higher HP with more peace of mind by using your 340 or an  early 360 because they are flat out stronger castings.
When it came time to selecting a block I had both at my disposal and chose the 360. I did this because the location of the 340 was 700 miles away, if it were now I would have went and got the 340 but it's not because there is anything wrong with the 360. It is just that the 340 actually came in 'cudas and 360's didn't.
 
The power potential of both is pretty darn close. The 340's crank main journals are slightly smaller so that means less surface area and the bore is larger than a 360. There are pro's and con's between the two but they are pretty miniscule. If you want to go over 450HP or so you should look into a forged crank and maybe even a Hughes Engines main stud girdle(especially if you want to go up to 6000 RPM). You will not have to use an external oil pump on any stock block even if you gou for the 426 cu. in. stroker but make sure you spring the couple extra bucks for a Melling HV pump.

If you want to sell the 340, the going rate for a short block that needs to be rebuilt but all there is about $700-$800. Personally I would keep it because who knows if you'll run across a 71-75 360 block and if you do you can't garauntee it will have everything like what you have on the 340.

Again, the book is a wealth of knowledge and the author has worked for Mopar's performance division for many years and knows alot about small blocks.
  
« Last Edit: August 17, 2007 - 06:29:56 PM by go-fish »

Offline ChallengerHK

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Re: Stroker Basics
« Reply #9 on: August 17, 2007 - 11:14:46 PM »

In a V8 car, turbo lag can be a good thing (as in more controllable).


Thanks for the info.  My opinion is that it's better to have more power and control it by keeping your foot from going all the way down that to need more power and not have it.

The down side is, there are certain thinkg you should equip it with, or have done to it. So between the added parts, and the slightly more cost of machining work, they end up about 10% more expensive.


10% doesn't sound too bad a price to pay.

Before I make my comment let me tell you why you should take my advice, I am not trying to come off as an LA block expert or a know-it-all, it's just that I have gone through all of this.


That's why I ask. One of the reasons I love this site is all the information and experience I can take advantage of.


The book is "How to Build Big-Inch Mopar Small Blocks" - by Steve Szilagyi. http://www.amazon.com/Build-Big-Inch-Mopar-Small-Blocks-Design/dp/1932494065
Get it before you do anything. It is the best reading material for the subject.


I've seen this book, and I'm glad somebody feels they can recommend it.

More info:  the 340 is built (very mild/close to stock), running and in the car, driven weekly.  Whatever I do it'll be down the road, so I'm in no hurry to make a decision or start building anything tomorrow.  One of the interesting things about the 69 motors is that they're stamped with the full VIN, so I know the exact car the block came from (a 69 Dart GTS). I've thought about contacting the GTS registry and seeing if that car has been registered and possibly see what the owner of the car would offer for it.

To whoever mentioned the centrifugal supercharger, I've been hinking about that as well. My thought was stroke the motor for bottom end and add the supercharger for top end.

The car will be purely street/road racing. No offense to the drag guys out there, but I've never been interested in going fast only in a straight line or only for a few seconds.  I want to be able to power my way out of a curve, run well on the interstate, and if I want to smoke someone from light to light, do that too.  In other words, I want it all   :grinyes:


"She'll make point five past light speed. She may not look like much, but she's got it where it counts, and I've made a lot of special modifications myself."

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Offline Chryco Psycho

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Re: Stroker Basics
« Reply #10 on: August 18, 2007 - 04:53:52 AM »
The downside to strokers is the rod ratio & piston height , shorter rod ratio pushes the piston more sideways up the bore & will increase bore & piston wear this can also decrease torque  , shorter pistons are less stable in the bores also potentially shortening engine life

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Offline ChallengerHK

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Re: Stroker Basics
« Reply #11 on: August 18, 2007 - 11:02:30 AM »
The downside to strokers is the rod ratio & piston height , shorter rod ratio pushes the piston more sideways up the bore & will increase bore & piston wear this can also decrease torque  , shorter pistons are less stable in the bores also potentially shortening engine life

Thanks, Neil.  I knew there had to be something.  Is there a stroker setup that minimizes these problems.  I'm guessing from your description that the answer is that the more you stroke, the worse it gets.


"She'll make point five past light speed. She may not look like much, but she's got it where it counts, and I've made a lot of special modifications myself."

- Han Solo, Star Wars

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Offline go-fish

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Re: Stroker Basics
« Reply #12 on: August 18, 2007 - 11:28:25 AM »
The 4" crank is the most widely used. There is a reason. It gives a good "safe" rod ratio. Alot of people have built 408's and 416's that have gone many passes and many miles.
Alot of your answers can be answered in the How To book. It is my favorite reading material of all time, LOL.

Offline ChallengerHK

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Re: Stroker Basics
« Reply #13 on: August 18, 2007 - 12:02:08 PM »
The 4" crank is the most widely used. There is a reason. It gives a good "safe" rod ratio. Alot of people have built 408's and 416's that have gone many passes and many miles.
Alot of your answers can be answered in the How To book. It is my favorite reading material of all time, LOL.

It's on my wish list  :bigsmile:


"She'll make point five past light speed. She may not look like much, but she's got it where it counts, and I've made a lot of special modifications myself."

- Han Solo, Star Wars

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Offline Chryco Psycho

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Re: Stroker Basics
« Reply #14 on: August 18, 2007 - 12:10:01 PM »
personally I use longer rods in strokers where possible to maintain as much rod ratio as possible which will move the pin up in the piston which is fine , in a street engine I fell sacrificing some CI to maintain rod ratio is more important as the engine life will be decent & you will make enough extra power at the same time

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