which stroker and why?

01Steeda · Jan 19, 2006

ok I have searched the forum, but havent found one thread that totally answers this for me.

here is the situation, I had overrevved my car awhile back and it looked like all i had was some bent valves. i had the heads replaced with stage2 patriots and stage 2 patriot cams. put down some good power and was pleased... turns out I had damaged the bottem end as well and it just took abit longer to become apparent.

Now the question. if you were to replace your shortblock.. which one would you buy and why?

03ghoststang · Jan 19, 2006

a big bore block,that is like .20 over because our motors dont need anymore stroke what they need is the cylinder to be bigger

01Steeda · Jan 19, 2006

thanx for the response.. I had gatherd that from most of my reading... what size (cu) would you think would be a good street car, but make good power

01Steeda · Jan 19, 2006

wow thats the only input?? I figured this to be a bigger subject

blackfang · Jan 19, 2006

Here is a write up a buddy and I discussed
Here is a quick write-up I decided to write so everyone here can know why exactly strokers suck and big bores make the power. First let's look at the stock modular bore and stroke. The stock bore is 3.552'' and the stroke is 3.543''. That stroke is HUGE already. A 351W has a 3.5'' stroke from the factory. They have an extra 73+ CID on the modular motors. This puts it in perspective on how extreme the stock stroke already is.

Now, combine that with a stroker kit and your piston starts leaving the bore. This is VERY bad at high RPMs as the piston becomes extremely unstable. Stroker motors just don't last. The HP/TQ gains are so minimal as well because the valves are still shrouded. The only time you want to use a stroker is when you have a turbo setup as turbos don't really like to rev high either and can benefit heavily from the slightest torque band increase. The reason these are so popular though is because you can use your stock block and you don't have to resort to using the more expensive aluminum block counterpart like you have to in a big bore.

Big bores are what make the REAL power. We're not just talking about HP either. They make great torque and LOVE to rev (which is just what a modular motor needs). Big bores increase the bore from 3.552'' to 3.7''. This is done by taking an aluminum block, boring out the sleeves that are already in it, inserting new, stronger sleeves and boring them out. There are 2 versions of big bores. One is the dry sleeve which doens't cost that much and can handle roughly 20 PSI on a blower. This is the one you want for a mild blower application or NA application. The other one is a set sleeve where they actually bore out the sleeve of the cylinder and insert a new heavy duty sleeve in. It is called a wet sleeve because the coolant is touching the sleeve; this allows for cooler temps. The wet sleeve can withstand basically anything you can throw at it. Aluminum blocks can be either wet sleeved or dry sleeved. Iron blocks can only be wet sleeved. As you probably guessed, wet sleeving is very expensive (about $1k more than normal dry sleeving).

Now, the reason the big bore benefits is this. On the stock motor, the valves are shrouded. This means that the cylinder isn't big enough to support the heads. Basically, the combustion chamber is bigger in diameter than the cylinder. Big bores fix this problem by unshrouding the valves. THIS, my friends, is the secret to why big bores are making the power and lasting as opposed to strokers. Remember this when you want to increase displacement. Oh, and don't even both with the 324'' big bore/stroker blocks as the rod ratio is all fudge up and they are just a problem waiting to happen.

To add, turbo's love exhaust mass. But certain companies will try to tell you, that strokers are ABSOLUTELY needed. They're not. If you really want to push high HP, go with a 5.4, it is THE BEST solution to that problem. A .020 4.6 can support 1000hp in a tight powerband with a turbo, as long as the turbo is sized according to the engine.

Also, you can big bore an iron block, but as Code mentioned, it must be wet sleeved. This process is somewhat cheaper than starting with an aluminum block, but the Darton M.I.D. sleeves needed are in scarce supply and cost ~1,500 dollars alone. The only time i'd recommend using an iron block in this situation is with a NVH 5.4 block used only in an N/A application. No other instance would such a block hold up to boost pressures. The one good side to this scenario, is that iron will cool much better and evenly across the cylinders than the aluminum counterpart. It will never be as tough and strong though

lgndracer · Jan 19, 2006

Good reading. Thankx.

03ghoststang · Jan 19, 2006

i have heard of (CHP) Coast High Performance here in Torrance, California that they have a big bore 5.0L or 5.1L mod motor but its not on their web page but i know that they have it..

01Steeda · Jan 19, 2006

I guess I should call CHP then.. thanx for the read.

stangGT97 · Jan 19, 2006

awesome write up

LS2 KLR · Jan 20, 2006

Had I known more about the big bores, I might have gotten one instead of my stroker, but most likely the 324, lol. When I had a 347 in my last stang I had always heard about how unreliable a stroker was and now hear it as well with my modular, though I'll agree the modular doesn't look as stroker friendly on paper.

MPH builds quite a few high hp modulars. Their most common setups are blown strokers usually making 600+rwhp. Like mine, many are daily driven and I have not heard of one failing due to being stroked As I said, on paper they look like stroking them could be eventually lead to issues, but have never heard of them actually occuring.

blackfang · Jan 20, 2006

LS2 KLR said:
Had I known more about the big bores, I might have gotten one instead of my stroker, but most likely the 324, lol. When I had a 347 in my last stang I had always heard about how unreliable a stroker was and now hear it as well with my modular, though I'll agree the modular doesn't look as stroker friendly on paper.

MPH builds quite a few high hp modulars. Their most common setups are blown strokers usually making 600+rwhp. Like mine, many are daily driven and I have not heard of one failing due to being stroked As I said, on paper they look like stroking them could be eventually lead to issues, but have never heard of them actually occuring.

Do a search on the corral, modular depot and such.I have seen strokers failing on those sites. In fact a few weeks ago there was one on the corral I believe of a stroker that went bye bye.

There are quite a few people whose stroker motors have had issues or gone south.

VTEngine · Jan 20, 2006

The guy on corral ran his motor out of oil. That'll ***** up a bigbore, stroker, stock stroke, pushrod, lawnmower, etc.

Yes the modulars need bore. Yes turbo's like stroke. If you don't believe me, do some searching. With the exception of Mihovetz, 90% of the high horsepower turbo cars are stroked. And this talk of 'strokers don't last' is internet hearsay gossip. I've built over 150 of them in the last 2 years, and they all run strong. The only failures have been tune related.

Yes, they do add to side load on the pistons. That is consistent with all stroked engines.

VTEngine · Jan 20, 2006

LS2 KLR said:
Had I known more about the big bores, I might have gotten one instead of my stroker, but most likely the 324, lol. When I had a 347 in my last stang I had always heard about how unreliable a stroker was and now hear it as well with my modular, though I'll agree the modular doesn't look as stroker friendly on paper.

MPH builds quite a few high hp modulars. Their most common setups are blown strokers usually making 600+rwhp. Like mine, many are daily driven and I have not heard of one failing due to being stroked As I said, on paper they look like stroking them could be eventually lead to issues, but have never heard of them actually occuring.

Well said.

blackfang · Jan 20, 2006

VTEngine said:
The guy on corral ran his motor out of oil. That'll ***** up a bigbore, stroker, stock stroke, pushrod, lawnmower, etc.

Yes the modulars need bore. Yes turbo's like stroke. If you don't believe me, do some searching. With the exception of Mihovetz, 90% of the high horsepower turbo cars are stroked. And this talk of 'strokers don't last' is internet hearsay gossip. I've built over 150 of them in the last 2 years, and they all run strong. The only failures have been tune related.

Yes, they do add to side load on the pistons. That is consistent with all stroked engines.

So then a SHM stroker should be no problem then right?

There are only 3 companies i would buy from you being one of them. However, you can't argue the fact they can cause engine issues and problems especially if not built right.

mrvax · Jan 20, 2006

What companies sell a BORED modular block and how much? It would be nice to have a 302cid or better.

VTEngine · Jan 20, 2006

blackfang said:
So then a SHM stroker should be no problem then right?

Aint touching that one.

There are only 3 companies i would buy from you being one of them. However, you can't argue the fact they can cause engine issues and problems especially if not built right.

The only proven fact of strokers, is they increase the side load on the piston. Regardless if its pushrod or modular. Strokers are good in some cases, not good in others. For n/a, bigbore is definately the way to go (which I've done for my engine, but I took stroke OUT of the engine, destroked). Blower combos with centri's, I like bore for rpm. KB's, I like stock stroke/bore. Turbos, I like stroke and/or bigbore. Everyone has their personal preferences and opinions. As for your last line, any engine will give you issues and problems if not built right.

blackfang · Jan 20, 2006

VTEngine said:
Aint touching that one.

lgndracer · Jan 20, 2006

Scott,

Thanks for chiming in. I have been looking at shortblocks, and have heard nothing but great things about your company. My current set up is in my sig. Your message about says that for KB applications you like the stock stroke with a big bore. I checked your site and only see big bore w/ stroke, or standard bore. How much would the big bore stock stroke short block run?

VTEngine · Jan 20, 2006

lgndracer said:
Scott,

Thanks for chiming in. I have been looking at shortblocks, and have heard nothing but great things about your company. My current set up is in my sig. Your message about says that for KB applications you like the stock stroke with a big bore. I checked your site and only see big bore w/ stroke, or standard bore. How much would the big bore stock stroke short block run?

For the KB's, because they make such insane power downlow, and instanteous boost, you only need a stock bore and stroke engine. Shoot me a PM with details about your goals. I don't want to get into pricing, cuz I don't need to get in trouble for spamming. I was here to add my .02 to the thread. Thanks.

03 Black GT · Jan 20, 2006

which stroker and why?

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