# Stroker kits and Breaking in



## JimmyFox (Dec 13, 2010)

I've never built an engine so that's why I ask this. If someone purchases a stroker kit (427) for their LS2, would they have to upgrade any of the other components on the engine? Also would you have to break in the engine. I've heard stories about having to stay under 50 mph for the first 500 miles. Any info would be great. Just trying to learn how it works.arty:


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## GM4life (Mar 18, 2007)

Most stroker kits come with everything you need for the short block. Going with that much cubic inches requires heads, cam, intake, injsectors, exhuast.

About breaking in engines you are going to get many different responses. The way I've broken in engines after I've put them together was: run the engine at 2K RPM for about 5-10mins to seat the rings, drive the car at varying speeds, not ripping on it, change the oil after 500, 1000 and 3000miles. No fast starts, keeping the revs below 3-4k rpms. Now this technique was for SBC's, LSx motors may be different, I haven't built one yet. Doing it that way I've had darn good running engines. Engines are never really broken in at 500miles you are just getting everything seated.

I've had older folks said they drive it like you stole it, if it won't break then it will never break. I guess some had good luck with freshly built motors that way.


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## dustyminpin (Jun 19, 2006)

Just know that you don't just slap a stroker kit in. I thought that was the case and almost bought one from Callies only to find out my speed shop doesn't do machining work and the only local reputable, trustworthy machining shop went out of business. The block has to be taken apart and clearance cuts/grinds need to be made for the larger crankshaft to fit. Also, 99% of your stroker kits are 402 c.i.d. That is most popular for LS2s. 

383s for LS1s, can go to 427 on LS3s and 440 on LS7s. You don't want to go too big and machine the walls too thin. If you go beyond 402 on an LS2 (assuming that's what you have), you have to go through the expensive process of having your sleeves machined out, bores opened up, and replaced with high dollar heated treated alloy sleaves that will hold everything together around the thin aluminum walls that are left on your block. I know a guy in California that makes a living doing that. Read an article about him making very reliable, very strong running 454 c.i.d. LS2s. But you're gonna PAY... Here is his website. Read up, you'll see all that's involved in what I'm talking about. http://raceenginedevelopment.com/pages/694927/index.htm


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## Poncho Dan (Jun 30, 2009)

I was thinking about a "kit" as well, but I'm pretty much settled on just getting a shortblock... it's a little more plug & play.


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## dustyminpin (Jun 19, 2006)

Poncho Dan said:


> I was thinking about a "kit" as well, but I'm pretty much settled on just getting a shortblock... it's a little more plug & play.


That's exactly what I'm doing. Saving up for a Texas-Speed 427 cid LS3. In my dream world that I like to live in with unicorns and lepricons and mustang owners that actually don't rev their motors at you everytime they see you, I would like to send my LS2 block out to the guys above and have them convert it to a 454... then drop it into a new Tahoe or Avalanche... then take the 5.3 from the Tahoe/Avalanche and drop it into my wife's Colorado... then take the inline 5 cylinder out of the Colorado and wipe my butt with it... Mwa Ha Ha Ha Haaaa...

K. I'm done. now.


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## JimmyFox (Dec 13, 2010)

Now not to sound like a total idiot, So with stroker kits you actually have to have the block machined? I was given information that it was just part swapping. Also thanks for the info


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## Poncho Dan (Jun 30, 2009)

I'm looking at 402's + 237cc cathedral ports with a 2.3L roots. Cheap, not so big, but thicker walls to handle boost without issue. Plus a home-made Svede so people can hear the compression of the rotors megaphoning out the front of the car for the "WTF?!?" factor. Turbos are so played the f**k out it's not funny, nor even mildly cool anymore. Almost as bad as nitrous. 

Oh, and I'll run it on corn juice so I can say I'm "going green" to any eco-minded person who wants to run their mouth.


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## dustyminpin (Jun 19, 2006)

JimmyFox said:


> Now not to sound like a total idiot, So with stroker kits you actually have to have the block machined? I was given information that it was just part swapping. Also thanks for the info


Not a dumb question at all. I thought the same way. Thought it was a direct swap. Actually had Callies make me a custom 402 kit to my needs and before I gave them the debit card number, called my speed shop to make sure they were selling me the right stuff. The shop owner said yes, they were selling me the right parts but they couldn't put it in for me because they didn't do in-house machine work (very few speed shops do, have to go to a full blown machine shop with lathes, mills, cnc's, etc.) There is not enough clearance in the stock block for the stroker cranks. That's why you get the crank that you do from GM. 

I know of one ballsy guy here in town that claimed to do his own work on his 402 stroker kit on his '05 in his garage, but you have to have the right tools, car lift, cherry picker, engine stand, etc. to pull it off and you better know exactly what the hell you're grinding/machining off for the clearance cuts or you're going to end up with a big pile of junk aluminum.


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## Rukee (Feb 8, 2007)

You could do the clearancing yourself with a die grinder, but your going to want the block hot tanked when your done to be sure all the metal shavings are flushed out.


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