I was wondering about this I heard. I was reading a message board post and this was they said. OK it was of people destroking a Chevy 350 to 327ci motor then overboring it 0.60 creating a 366ci motor that revs "out the moon" (revs really high at about 10-17K). I dunno if it was turbo charged it what I just heard this and wondering if anyone out there knew of anything like this? Would it be worth it?

I'll find the tread that had this and i'll post it in a lil while.

 

here it is guys i found it. Is this possible?

"youre right, .06 vs. .25 is a big difference. but suppose you destroked a 350 to a 327, then siamese bored the cylinders to accommodate a 4.25inch bore. a 366 that'll rev like nobodys business, provided the rest of the motor could support it, a 10k rpm short block reliably, or at least more reliable than a 7000 rpm 383, with essentially square bore geometry. 4.03 inch bore, 3.875 inch stroke.
366= 4.25 inch bore and 3.25 inch stroke. add 12:1 compression and shake vigorously. some huge port heads, super stiff springs and a high lift cam, high rise manifold and a 750 cfm carb, and youre probably close to 500 lb-ft at 7000, which comes out to 666 horse, aka the evil mouse. and im not sure which is turbo, but the one that is is faster. anyway, just sayin that the friction coefficient will determine your rev limit due to heat and thermal breakdown, hence the reason for the term redline. the highest point your motor is rated to operate. not to say it wont rev higher, but youre takin a chance. ps, rotary's are friggin cool"

 

sort of the other way around when gm did it. they upped the stroke of the 327 from 3.25 to 3.48 and the 350 SBC was born. not sure why you'd want to remove the extra displacement unless you're wanting to limit your preformance. factory original 327 cranks are all SJ except for the finial year of productio, 68, and 350 blocks all accept LJ cranks.

 

Siamese bore the cylinders to 4.25" bore? Thats not going to work. Thats kinda like trying to bore a 305 into a 350, it just doesnt work. You'd need to use a 400 block, and IMO thats a perfectly good waste of cubic inches.

 

damn max i missed that the first time. i want to get that siamese bore on my new engine too.

 

Wow, that thread is the funniest thing I've read all day

 

People who have never built any motors always seem to think for some reason that the smaller motors are going to go faster somehow. It's the strangest thing. And of course, others who haven't built anything, but rather rely on magazine articles and such for their "knowledge", come up with the same sort of strange ideas too.

All of us who were building motors when the 350 became available, quit building 327s and 302s and 283s right then and there. The reason is quite simple: if you take a dollar and apply it to one of those, and see what you get; and then take the same dollar and apply it to a 350, and see what you get; you'll find that you get more out of the dollar with the 350, every time, no further questions, no exceptions. The 350 will simply go faster every time. Or, to turn it around the other way, if you decide how fast you want to go, it's cheaper to do it with a 350 than a smaller motor.

People who have never had anything with a higher gear ratio than 3.23 seem to think that just because those smaller motors use a short stroke crank, they will spin to a higher RPM than a 350. That's partially true, for the bottom end; but then everything else has to be set up for higher RPM use too. The valve train, the cam, the heads, the gears, etc. Have you ever had an alternator, or a clutch, or a water pump explode from excessive RPMs? I have. It's not much fun. Kind of takes all the fun out of it, in fact, especially the clutch: at least I still have feet, unlike some people I know that had the same thing happen to them.

There's a good reason nobody builds those motors any more. They lose races. Anything you can do to a 327, you can do to a 350; and the 350 will produce more power. Period. There can be no argument, this is not a question of belief, it's a simple fact.

So, those who want to be "different", go right on ahead. I'll continue to be faster than you. The "difference" you'll accomplish will be that your speed is "different": it will be less.

If you "destroke" a 350 with a 327 crank, you come up with {drum roll please} a 327. They have the same bore. A 327 .060" over is about 335 or 336, not a 366. You're not going to get much of a performance improvement by doing normal maintenance (boring). You can't bore a 350 block out to 4.25", that's a quarter inch of bore, and there isn't that much metal there. You can't even take a 400 block and bore it that far; 400s are risky at .060", you will lose probably a third of all 400 blocks if you bore them that far, from hitting water.

That whole post is a bunch of non-participant bench racing mouth diarrhea from somebody that doesn't have a clue what they're talking about. It is drivel, not information.

 

OK ok. I know yall must think I'm a dumbass for making this post. I just came across some information in another message board and thought it sounded kinda strange. Ijust posted it to see if anyone every heard of this kinda thing. Yes I have built a few motors as a hobby. I'm no professional engine builder but I built my share of 3 motors and learning more with everyone. As for one thing I LOVE 327s! Sure you get more hp from a 350 or bigger but I love my quickness (rev) and short stroke. At the drags I dusted a few big blocks and a handful of 350s with my 450hp packed 327 in a S-10.
Any ways thanks for clearing up the BS and answering my questions.

 

nice try at a save DL :lala: :lala:

 

A longer stroke will increase the leverage that's applied to the twisting motion of the crankshaft.

Anyone here ever use a "cheater bar"? You put it on the end of the wrench so that you can easily apply more torque to the nut or bolt. When a crankshaft has a longer stroke, i.e. that's what it's doing. The offset of the rod journal is moved further out from the main journal. This increases the amount of leverage for the piston to "push" down on the crank. Since this increases the applied torque, and torque is what accelerates a car, it will accelerate the car quicker.

The other reason is so obvious that too many people overlook it.
IT INCREASES DISPLACEMENT!!!!!! The farther down the piston travels on the intake stroke, the more area there is for air/fuel to fill. The more air/ fuel you can get into the engine, the more power it will make.

Since the 3.25" is easier to push up to compress the air/fuel in the cylinder, there are less "pumping" loses in the engine which is why it's easier for the 327 to rev higher, and usually it does make more HP than a 350 over ~6500 RPM. But it will not make more PEAK HP than a 350, nor will it make more HP anywhere below ~6500 RPM. And lets not even get into how much torque is lost.

It just goes to prove the age old saying that "There's no replacement for diplacement"!!!!!!!! Why do you think that NASCAR crews build their engines as close to the max displacement limit that's allowed? If they thought a 327 would be better than a 355 or 365 or whatever the limit is (I forget), then that's what they would build. But they don't and there's a reason for that.

 

interseting..

CamaroDriver, the link in your sig scared the crap out of me! lol

 

Nice point CamaroDriver I'm not knocking a 350. They are great motors. I like my 327 b/c I use it in drag racing and it gets me to point A to B the quickest. Now NASCAR is a endurance race. Larger displacements work better in endurance. I raced Baja with a SBC400 in my "fun" truck. Worked great. I lasted a long time with 40gal of fuel. I wish a big block wouldn't burn **** loads of gas so quickly I would have used that instead. Matter of fact Harleys have a big displacement and long strokes b/c these bikes were meant to be rode long and hard at high RPM. I have a uncle that rode 500miles to Sturgis at almost WOT but not pegged out and the motor surprisingly didn't "detonate" or explode.

 

Naw, you've still got it wrong. It's the area under the HP curve, not how quick it revs up under no-load that produces lowest ET. A 350 will always produce better times than a 327, everything else being equal.

A 327 is not a better drag engine than a 350. It's not a better street engine than a 350. It's not a better road course engine than a 350. It's just an older design and more sentimental (although I don't know why - they only made them from '62-'69, the 350's been around for over 30 years - they made 283's from '57-'67, nobody's sentimental over them).

I would take a 327 over a 305, though. Or 283. Or 307. Donations chearfully accepted.

Come to think of it, the "sentiment" thing applies to Harley's, too. Notice what they've been doing the past few years?

Who says BBC's are fuel hogs? It's the total "package", not the basic block shape that matters.

 

This only holds true when the amount of applied force is enough to generate more torque with that extra distance. A 350 will always make more torque than the 305. According to your theory they should make the same amount of torque beacause of the same stroke length.

Why don't they?

Because the extra stroke needs the extra applied force to generate the extra torque. The 350's 4" bore creates more combustible surface area and in turn creates a more efficient burn and creates more downward force onto the crank; and that's where the length of the stroke comes into play.

 

OK....... obviously you missed the first topic of what I was explaining. "Why longer stroke is BETTER!!!!!" That is the case in point.

If you wanna play the 305 game, then put on your gloves buddy.

A 3.735" bore with a 3.48" stroke (a 305) will have more torque than a 3.735 bore with a 3.25" stroke (a 285).

You gotta compare apples to apples. That's why I didn't mention the bore issue since the 327 and th 350 have the same bore. After all, isn't that what we're discussing here? The 350 vs. 327?

 

The only reason I explained it was not to prove you wrong in some sort of way, I was stating it for the rest. Now that you have explained it, it makes things more clear now too.

Im not here to fight with anyone.

 

don't listen the people claiming their genius is about the 327 being slower than the 350. My fathers best friend has race'd dirt track cars since I can remember and his 350 destroked to a 327 bored 40 over with his isky cam flow bench heads oversized valves roller rockers. knife cut crank is the fastest thing on the track. I don't care who replies or says what he has got 400 small block 350 small-block 327 small block. And 60 overs is almost too much for any motor. But the 350 destroked to 327 produces the same horsepower is a 350 only quicker then the 350 400 even Big Blocks all of the above have a nice day good luck with your Motors..
oh and as ridiculous as this may sound the 327 become obsolete because they were so dangerous. Simply because of the RPM they can hit so quickly. Last thing the 327 and the 350 have the same bore. And if size meant anything a cow could outrun a rabbit ((.no sense in anyone replying I'm not arguing there's some history for you all.))

 

First post is to resurrect a 18 yr old thread lol

 

Nothing wrong with bumping a 18 yr old thread, maybe feeling a bit nostalgic lol

 

Well 18 yrs later there is no point at all in building a 327 unless you are dead set on doing it because someone gave you one for free

theres nothing a 327 can do that a properly built 350 can as good or better. Rpm?? a 3.48 stroke can go as high as pushrods will allow you to do. Todays rods and rod bolts with light piston designs can take it. And the cubes will allow for more power

 

LMAO @ the nonsense in this ancient thread. Gotta love the interwebz.

 

Only things I know that can rev to 17k are some V10 F1 engines from the early 2000s. And that is some trick valve train tech like pneumatically assisted valve springs.

That said, I did build a few engines that rev out to 50,000 - 60,000 rpm. But they only had .21 cubic inches and made about 3hp.

 

RPM's..... and that's why airplanes went away from piston engines (that, and the inherent issues with the pop blades breaking the sound barrier) and went instead to jet turbines. It's happening to cars also. That's why engines are decreasing in size, and getting turbochargers. A turbo is essentially just a teensy jet turbine with a single compressor and no burner.

GD

 

Yeah boost is the cure for all things

 

A bear can outrun a human. Hows that for your size comparison? Your story is so full of BS it'll stink for another 18 yrs when someone else with a cool story about their daddy's, boyfriend's, mother's, uncle's, neighbor's friend who saw a car once bumps this thread again.

 

I've had some of those.

 

Go away baitin’

 

I'm so disappointed. I was looking forward to reading a good thread on destroked SBC engines.

For those interested, read this and give your thoughts: http://www.purplesagetradingpost.com...%20engine.html

Fast355, I'm inviting you to comment. And Skinny Z, you should really find this interesting. Sofa, how about it?

 

Sofa or RB?

 

Destroked engines are for turbo limited classes or maybe for long rod roundy round cars. Theres no reason to sacrifice cubes on a street or drag race motor imo. Longer stroke pulls harder on the intake port so if you have good induction system then you will make good power, maybe even more so than a shorter stroke deal. There are variables as with anything

 

It's long been known that increasing the stroke in certain engine applications will increase the torque output, all other things being equal.

But giving away displacement to do so might make sense if one were competing in some cubic-inch-restricted racing class (as one example, the '60s Trans Am racing limit of 305 ci spawned the destroked 327, a 4x3 302), but makes no sense for a street engine where cubic inches rule. Additionally, changing the compression height made necessary with the use of a longer connecting rod usually calls for custom-made pistons and the possible problems associated with moving the wrist pin up into the ring land area.

ETA:
BTW, a 327 overbored .060 (not a good idea in and of itself due to core shift in those ancient blocks, possibly leaving one or more cylinder walls whisker-thin if not actually into the water jacket) produces 336 ci, not 366 as opie stated.

 

If your gonna do something like that, just buy a 6.0l ls and destroke that engine. Put a Turbo on it and make 1200hp. These old SBC engines are dead as disco. Gen 3/4/5 engines are where it's at

 

Is it time for the unmasking?

 

http://www.nelsonracingengines.com/~...er-Series.html

 

Just go to the track and see how "all the fast cars" are powered by 327s, and how many races they're winning. Then compare how "all the fast LSx cars" have combinations with shorter stroke (fewer CI) and how many of those are also winning all the races.

Won't take many weekends of data gathering before the FACTS emerge and make themselves plain.

While it is true that a short-stroke / large-bore offers some advantages over a long-stroke / small-bore engine of the same displacement, that does not automatically guarantee that reducing the stroke and the CID together guarantees a superior combo. Otherwise, in the 70s when 327s were a dime a dozen and 350s were "high tech", people wouldn't have abandoned 327s so instantaneously. Getting beat because you're closed-minded SUCKS, not least because sometimes it hurts to admit you were WRONG almost as much as it hurts to lose.

 

3.25" stroke in that block is giving up ~70 cubes compared to a 3.875" stroke.

I prefer a longer stroke and smaller bore to get my cubic inches for a street engine where a broad torque curve to pull against tall axle gears and a sub 4,000 rpm stall speed. If I have a block with a big bore like a 400, the only reason I would decrease the stroke is to meet class displacement rules.

I have built a 5.94" rod 302 out of a 350 Vortec and L99 4.3 Caprice crank and rods. It ran really well in a light car with a T-56 and 4.10 rear gear. That being said the same 350 block stroked to 396 with a 3.875" stroke would have been alot more fun to drive even if the car had 3.23 gears.

My 99 Tahoe has what is essentially a stroked 454 with revised heads on it the GM 8.1 Vortec. I actually prefer the 496 to a 502 for a street application. Even with the larger HO Marine cam at 9:1 compression it has tremendous off-idle and low end torque. I left the 3.42 rear gear in the truck even with 32" tall tires. With the 4L80E it cruises down the highway in 4th gear at about 1,900 rpm @ 75 mph. It is also perfectly happy pulling along the Tahoe at 1,100 rpm in high gear around town. It spends alot of its time running in lean cruise mode.