Hey I was reading this article about "the 350 chevy should have built", what caught my eye mostly on it was the flat mid to high torque curve with 400 pounds throughout 2800-5200 rpm, freakishly high compression 11 to 1 and running on 87 octane pump gas. All this from a de-stroked 400 sbc. Here's the article
http://www.purplesagetradingpost.com...%20engine.html

Now putting that into a third gen, could it be a daily driver? and what would you have to mod on the third gen to have that thing inside it...could it run with the ccc q jet? what to do for the 700 to accept it? I would like some feedback on this if is not much trouble thank you.

 

Yes, it could be a daily driver. No, you wouldn't have to modify anything. Yes, it can run with the CCC Q-jet. No, you don't have to do anything specially for the 700R4.

Most importantly, no, it's not worth the trouble compared to a standard 350.

 

Dang that was fast heh heh, well sounds like I would trouble myself with it though it has good power and running cheap gas and i don't think ill get low miles in it either. On the other hand further research has yielded that 400 small blocks have cooling problems, although says that with the correct cylinder heads and some minor mods it can be fixed. Now back home this motor shop is selling a used 327 for a couple of hundred dollars i heard those are pretty reliable and make good power. Wich would you recomend taking this in consideration; I live in a very hot place (Puerto Rico) so 86-90 degrees is the average temp and humid too, I'm a little frugal but i do like performance also lol. Thank you.

 

For cold northern climates like Puerto Rico I'd recommend a run-of-the-mill 350. If you have to rebuild it, you can make it a 383 if you like.

 

The 400 cooling problems are easily addressed and any decent machinist would handle the mods necessary during block machining. What made the 350 in this article interesting was their use of 6.25" connecting rods to create very close to a 2:1 rod to stroke ratio. 2:1 R/S is ideal, though it would take more than this post to explain why. The 350 built in this article would be a much more durable motor when used in a racing application than a factory config 350. (It would be even better if they had used a block with 350 main journals and 400 bores rather than the heat retaining spacers.) However, the added cost makes it not really worth it for a street application.

I do like the concept of destroking to allow use of longer connecting rods. Reminds me of the 377 I plan to build soon.

 

Yeah right.

Put down the pipe and back away slowly.

Then once the effects wear off, think:

Earlier you said

In that application, explain the benefits of spending extra money to reduce your CID, WITHOUT referring to the "article".

Tell us all about how everybody else goes faster with MORE cubic inches, and then tell us logically, rationally, and with clarity and precision, how you're going to violate the rules of the known universe.

Basically, you are spending ENORMOUS extra $$$$$, and using all that as the weapon to shoot yourself in the shorts.

{chambers pistol} BLAM!! All I hit was the little one on the right. BLAM!!!! Dammit! That time I just got the little one on the left! BLAM!! BLAM!!! BLAM!!!! There! I finally hit that big long one in the middle!! That'll teach it. {zips fly}

Smartest thing you can do with a 400 block for a

is forget about magazine articles, put a 400 crank in it, and build a 400.

Next smartest thing you could do is get a 3.875" or 4" crank and ADD cubes instead of TAKING CUBES AWAY.

 

I took cubes away from a 400. I did it cause I had the parts. It is nothing earth shattering. It runs well but I have a 383 that runs as well or better.

 

Some decades ago, I built a 377 for somebody. They just HAD TO HAVE it. I tried to warn them what was going to happen. But they just HAD TO HAVE it, had got the idea in their head that it was going to "rev to the moon", (familiar sucker line, that) so I built it, built it good, and they paid, like a good customer. Ran OK for what it was.

They were mad at me because they got beat so bad by 400s. (circle track racing, dirt) They got SMOKED coming up out of the corners, EVERY TIME. No matter what, they couldn't hold the low line against an attack. They wanted me to do something about it, on my own dime. I politely declined.

I tried to warn them. I tried to remind them I wasn't the one that talked them into doing it. Didn't seem to help. I don't recall ever building another motor for that customer.

 

Yea I still jones for another motor. Though I have been debating on seeing what forced induction would do. I will say my throttle response is crisp, but good tunning can do that. The new V3 universal setup from Vortech seems like a tidy solution.

9 times out of 10 more cubes wins. My dyno curves are pretty, almost textbook.

 

Did anyone actually read that article, and notice how retarded their logic sounds? Longer rods = more dwell at TDC = more resistance to detonation? Dwelling near/around TDC encourages detonation


Another thing that they fail to take into account is that the piston speed is dependant solely on the stroke of the crank. The rod does not factor in. So everything they say is complete BS.

 

I was just asking for some insight and info, lets see if i pay $ for something and i get what i paid for why would i be mad about it? in a race there are so many variables, including weight suspension, brakes, driver skill not just cubic inches, so rationally speaking a smaller engine in a lighter vehicle and forced induction could very possibly beat more CI. I want something durable and after I spend the money on it, wont have to spend more on it I liked the idea of "the article" cause 1. where i live i dont see 100+ oct gas anywhere 2. 4 out 10 people here have toyotas, other 4 of those 10 have mitsus and hondas the other 1 miscelaneous 4 cylinder rice machines...anything above 350 hp and tq is pretty much overkill unless you are at the drag strip..and im kinda bored of drag races i really don't care if i get beat at em, hell my best race was downhill on bone stock honda accord 2 door ex vs a turbo eclipse gst could probably tear me a new one on the strip but down hill (and it was steep) I was almost just as fast as he, then we hit the corners poor bastard always braked too late, took s@#$ty lines and always came out of the corner slower than me he did catch up on the straight then we hit another corner 2 minutes later I put my signals, he's beat only one last curve and right after it a crossroad with a stop light fool gave me a ***** fly by and put his flashers, (couldn't accept defeat) slammed the brakes spun out crashed and looked really stupid, he came out w/o a scratch thank god and had the luck that hes car wasnt totalled and could take him home after it. 3 most people that have muscle cars here have either a 350 or 454 i don't get to see a lot of 383's but i have seen a few much less something de-stroked idk sounded like fun having something different too so i was looking into the de-stroker and 327's. 4. yes daily driver i liked driving the car i like all the time not just sometimes.

Im not a mechanic (my friend is) compared to most of you i dont know ... like id said im not here to debate i just wanted experienced opinions on the subject. there u go PR is a fun place to drive with lots of mountain roads kinda like those ricers in japan but tighter.

Another thing will that engine from the article rev a lot? is not that i like or dislike high revs but i do know too much rpms cause issues i wouldn't like it too much it it goes beyond 7000

 

Just in case you get the wrong impression, I wasn't directing any hostility at you. Just at the article for being so misleading.

Everything they say is wrong. Its simply not true. The destroking doesnt allow you to run more compression. It will still be in the same boat as any other engine with high compression. In fact, it will be worse off as youve now increased the size of the combustion chamber, and the ammount of distance the flame front has to traverse. This increases the likelyhood of detonation.

If you want a good engine that makes power on regular 87, heads with good combustion chambers and proper quench (if applicable) will get you that. The improved chambers (such as fast burns or similar) and proper quench will ensure that there is turbulence in the cylinder. This leads to a faster burn, which needs less timing, and is more efficient as you spend less time compressing a burning mixture.

As for displacement, take your pick, just dont bother destroking a 400

 

You might want to do some research about that.

 

I actually calc'd the equations, and it does have an effect on velocity (bad wording on my part), but not the position with respect to the crank (damn you for making me think! ). The velocity will be different, but the dwell times will be the same (more or less).

 

The thing about piston velocity and dwell time is true; just, doesn't have NEAR enough effect to allow raising the CR by 2 full points and running a race motor on watered-down cat pee.

If the rod/stroke ratio were infinite (very long rod), a graph of piston position would be exactly a sine wave. As the ratio decreases (real world), the upper and lower halves of the wavefomr become asymmetrical. Do a "thought experiment" and consider what the piston position graph would look like if the rod length and the stroke were exactly equal (1:1 ratio); you would see that the piston would be at BDC, sitting still, for 180°, and ALL of the actual motion would be compressed into the other 180°. The PEAK velocity would be higher, and the amount of time it spends less than, say, 10% of the way down, would be similarly shortened.

Because the piston approaches the head more slowly, there's less of a shock wave created inside the cyl, and that's where the reduced tendency to detonate comes from.

The amount of change that can be implemented in a REAL WORLD, PRODUCTION block like a 400, is trivial. Especially the part about 11:1 compression on 87 octane. While it MIGHT be possible to get a couple of tenths of a point of extra CR without running into detonation, IF ALL ELSE THAT CAUSES IT WAS ALREADY MINIMIZED, it's not going to produce results of THAT magnitude, BY ITSELF. You can get far more results by simple attention to detail: chamfer the top of the cyl wall, chamfer the edge of the chamber where the "bowl" meets the deck, radius the valve margins, etc. etc. etc. to eliminate "hot spots"; those things are all but FREE. Then, zero-deck the block. Then, ceramic-coat the top of the piston, inside of the chamber, and exhaust port, to retain the heat of combusstion INSIDE the cyl and avoid heating up the parts, all of which is damn near FREE especially compared to exotic parts combos forged from pure virgin nonobtanium alloyed with irrpelacium. IOW, UNTIL YOU DO ALL THOSE OTHER THINGS I MENTIONED, the R/S ratio is NOT the "low-hanging fruit" in terms of opportunities for COST-EFFECTIVE improvement.

While its existence is mathematically true, the actual usefulness of the effect is GREATLY exaggerated. I can assure you, the engineers at EVERY CAR COMPANY IN THE WORLD aren't engaged in a giant conspiracy to keep you from enjoying the benefits of it. I can also assure you, if there were some kind of cost/benefit advantage to changing that ratio and accpeting OTHER compromises that would go with it (for example, narrow rings packed close together all jammed up at the very top of pistons, or even wrist pins intruding under the oil scraper rings like racing pistons), SOME ONE OF THEM would be doing it.

In the case of yerbasic backyard hot-rodder like us, it is a bunch of theoretical pie-in-the-sky spank-off that will MASSIVELY drive up the cost of a rebuild and produce few IF ANY benefits that couldn't be FAR exceeded at a tiny fraction of the cost in other ways.

Forget the article. Put your feet back firmly on the ground. Be practical. Don't outsmart yourself: cubic inches will ALWAYS win on the street, within reason; and ANY stock configuration is prety much "within reason". If you've got a 400 block, build a 400 and laugh at the short-stroke loser (which he WILL BE) all the way to the bank.

 

I derived the equations and found that to be so, but posted before w/o thinking (it happens). For similar lenght rods (>1:1) ratio, the difference becomes much less pronounced. To quantify it, the difference in distance traversed by the piston wrt crank angle between 5.7" and 6" rods in a 350 for a rotation from -45 btdc to TDC is only about 2%. The dwell times are more or less roughly equal. Hardly enough to justify their claims.

 

Wanted to build a 377 bad also as I love the large bore for breathing and enjoy a high spinning motor. Machinist was dead set on talking me out of it, figured it would make more power than my 350 would. At the time there was a crank out that didnt require bearing spacers but never saved the info and couldnt find it. Wound up scrapping the idea. A 383, 396 or 400 for a street motor is much better.

No real overheating problems with 400s Im aware of just drill that steam hole in the head or get yourself an aftermarket block they have huge water jackets on them.

 

Interesting, never thought of it in those terms as the peak piston velocity with a SBC at 6k is only about on the order of 20% the speed of sound at sea level. In a race engine at 10-20k, though, I suppose that could become a considerable effect as the piston speeds increase.

 

Puerto Rico is a cold northern climate?

 

It is from here.

 

I wouldnt even consider where I live a cold,northern climate and Puerto Rico is considerably less cold and northern than here. If that's your only criterium then 95 percent of the world is "cold northern climate".

I just find thais whole train of thought fairly odd. If you live anywhere except a tiny equatorial range, you live in a cold climate and should build "run of the mill 350s"? You dont qualify that statement with any relevant info for other people to have any idea what your reasoning is.

(For the record wikipedia lists puerto rico as a tropical climate)

 

I think Apeiron was "joking". He has a rather DRY sense of humor...

I'm glad dimented and Sofakingdom came into here. The humor and ACCURACY of the information is much higher.

I was going to comment that I *thought*, with two engines with "identical" displacement (lets take a destroked 400, vs a stroked 350), the one with a larger bore and shorter stroke, while being able to rev faster, and fit larger valves in (to a degree....), has a larger flame front, as is therefore MORE prone to detonation, compared to a smaller bore engine.

This is all wonderful "pie in the sky" stuff however. As sofa mentioned, the real world is much simpler.

 

When you live at the equator I'm sure this is true.

I've always found de-stroking silly for any reason. Spend the extra cost of making it smaller, on making what you have spin higher and make much more power.

 

Ok to end the discussion on Puerto Rico were are in the Atlantic in the Caribbean sea its tropical climate and is very hot and humid,its winter and we still get solid 92 degrees farenheit, during the summer its coomon to have 100's most of the week, we are at 18 degress north to 65 degrees west, climate is very similar to Costa Rica believe me I was near Costa Rica on a vacation (Panama), also heard our climate to be comparative to Hawaii our little coqui frogs that couldn't live anywhere but Puerto Rico found a home in Hawaii so I guess is pretty much the same (we are a US territory too just in case)....there...

Now back to the engine and "article" matter. Wow thats a lot of info so I'm gonna have to digest it a little bit for now, but I'm desisting from the idea of the de-stroked 400, i guess im safer with a 327 which has already been built and tried. Seems like everything they write on magazines is BS lol. Anyways i don't want a 350 every Camaro here either has one or wants one. This Xmas im getting my carb rebuilt, and some long headers with full custom exhaust (make a real dual exhaust)....so most of you agree 400 destroked is a bad idea, and yeah sounds like a lot of work to get it right, some insight on the 327 anyone here has run one of those? are they good and reliable?

 

Hmm? I guess Im not talking to a group of serious racers. Myself, I build my own motors as close to NASCAR spec as possible, retaining steetability. For me, having specialized in engine performance and drivability for about 30 years, making my extreme engines streetable isnt that hard. As far as 400s beating 377s in circle and dirt track, we need to move from talking about back yard wonders to seriuos NASCAR engines.

Ive built a few 700+HP 377s for NASCAR competition. The difference between these and the not so bright who run 400s and the really unintelligent who run any kind of stroker at consistent high revs, is that my 377s ran the entire season, finishing race after race in the top 5. Outpacing plenty of 400s. Of course the 400s and 383s usually ended up on trailers with something expensive broken.

Concerning the effect of higher R/S ratio. As I said before its far too complex to be covered in a post. One quick point, higher R/S ratio produces a less detonation prone engine and higher top end power. Yes, its really true, longer TDC dwell really does reduce detonation. Judging from the tenor of this thread, its appears a waste of time to even mention it to this group. BTW, 11:1 compression with 2:1 R/S, the right set of aluminum heads and a mild cam? No problem whatsoever. Would I build an 11:1 engine for the street? No. As for 87 octane, only a fool would run a high performance engine on cheap gas.

 

No, if you live anywhere in the world you should build a run-of-the-mill 350. The climate you're going to live in means next-to-squat.

 

If you're not displacement-limited for some sort of weekend racing class, destroking a street engine makes no sense.

 

All of the merits of the destroked engine listed here are for the most part valid. I think the point that is being missed is there is a reason the 377 is not envogue anymore. Plain and simple materials. Currently there are parts available with material properties that far exceed anything we had 10-15 years ago for a resonable price. With that being the case the need to come up with strategies to reduce rotating assembly speed is just not as important as it used to be. A 5140 Eagle Crank, Scat rods, and Mahle pistons will allow big displacement engines (383 and larger) to turn good RPM without any ill effects and it does not set you back too much money.

many manufactures play the displacement versus stroke versus assembly speed. Look at ford's motors. they all are a spin on this. The latest ones taking adavantage of new material science and going larger displacement.

I like my my 377 don't get me wrong. After building it though it is easy to see that the host of advantages listed in the math does not add up to much in the real world, not as much as displacement and material selection. If you are on the very edge of your hardware's ability and was looking for the last lever to pull for, this may be the ticket, but street cars usually do not fall into that catagory.

Being Detenation resistant is just one lever. I will add my motor is extremely resistant to pre-ignition to the point I loose power before I get knocking! Is it worth missing a few cubes,,, eh probably not. i would rather have the cubes and by a better pair of heads.

 

I didn't think posting this thread would generate such controversy. One side says de-stroking is good, the other says absurd. Mmmm, one side says more cubes will win always, other says not quite. My personal experience on cubes is...my old man has an Infiniti G35S 3.5 litre right? i got 1.5 liters or so more right? and that thing always tears my current Camaro a new one; although it was pretty even match when i had my 1990 iroc he still beat me by a little so more CI does not win here so it depends on the situation and how much $$ you spend on a particular engine. the 40k+ car beats the 600$ car lol. Anyways theres a lot of controversy on the subject.

 

Displacement wins when you compare two equally-built engines. You're not making an equal comparison when you compare the G35S with your Camaro.

 

Actually that is affected as well. Plot the position of the top of the piston (for simplicity you can just do 0 and 90 crank degrees) with different length rods. You will find the position is different between different length rods. This is how the velocity is different between the two as well.

Destroking is just a silly idea. If you have a 400 block, build a 400.

 

That only comes from those with a personal ax to grind who have no real world experience against others getting 100% from their setup. This is why when you visit things like Top Fuel, NASCAR Sprint cup, F1, etc... they're all AT the CI limit. They are not leaving cubic inches on the table to make more power by having less. I'll let you figure out why that might be.......

 

This thread is pretty well tame if you ask me. Trust me when a bunch of testosterone fiends start to really disagree on things it's much uglier, names are called, mud is slung, feelings are hurt, ect.

All things equal cubic inches wins every time. That doesn't mean cubic inches always win because seldom are things equal, like in your case vrs your old mans G35. Build your 5.0 to peak at the RPM his 3.5 does and see how many car lengths you put on him.

 

I said that a few posts down. But, its only two percent or so difference on the last portion of the compression cycle. Hence the "more or less" comment, but should have elaborated more on my part. The velocity and acceleration are subsiquent derivative terms of the position, and the effect on those becomes more pronounced when plotted. I think Id probably consider longer rods for changing those as opposed to trying to raise the CR.

 

As far as cubes go, everyone wants more, even the hoda guys running thier N/A 4-bangers out to rediculous RPMs to get the power they need. Theyre running the larger engines and strokers. Even though they dont stack up to a V8, its still impressive what they can achieve, even if it has to come at RPMs above 10k. More displacement = more power potential for a given RPM.

 

Ok this is one of the many places where we sometimes race:
http://www.youtube.com/watch?v=4C9qWYKUoa8

Im reducing weight a little bit and really not looking to be over 400 hp (would be too dangerous) this is not the drag strip, nor the highway and much less a closed circuit, is a lot different. my main contender is my crazy old man (and we almost never race) my best friend who races a 240 sx that i tear a new one, he's getting himself a wrx subaru prolly sti too and the wrx is gonna be even harder to beat probably than the g35 in those corners, so im needing good response w/o forced induction. The article caught my eye i made a thread to see some opinions , i researched a lot on the 305 and is a waste of money trying to make it a good responsive engine (it can be done but it cost more than getting a new better engine like the fabled 350, wich i dont want ,and the 400 but sounds too big, so the 327 cought my interest since old corvettes had em and the de-stroked 400). So there it is. so im looking for good response, durability and dependability but also want my car to be daily driven w/o spending 40$ in gas every 3 days so really big bores is out of the question.

 

Whats wrong with a 350? Theres a reason everyone has one. Theyre cheap, plentiful, durable, and they get the job done. If you stick with a smaller cam and run good heads, the engine will get good fuel economy and still make reasonable power.

As far as that road. Damn! Id be kinda scared to race down that. One wrong move, and you'll end up wrapped around a tree.

 

It is kinda scary the first 5 times or so, then it gets dangerous when you get accustomed to it and become overconfident. But i think is the same guidelines of precaution in any road or circuit. Overconfidence kills. Went over the border once long time ago in my mx6 (i was young and really stupid) braked too late and i under-steered went over the border on a corner that had no guardrail... Funny thing is i got 2 bruises and the car had only minor cosmetic damage front bumper got banged fog lights got trashed hood a little warped (fixable) and the rear stabilizer bar got broke when the tow truck got me out of the small cliff... I was lucky though i coulda been worse, I take no unnecessary risks now even if I lose, pride wont make you race another day right?

 

I often ask my self the same thing about the 305. If your bottom end is sound build it up and thrash on that until it gives or your ready to move on. You'll find plenty of people with 350-400+ hp under 6,300 RPM. Everything transfers over to a 350ci block minus the pistons so again why not? If you learn from other peoples success and not their failures you'll get much more out of what you have.

 

DaveC S1 Makes a very good point. Advances in internal component strength and weight reduction make strokers increasingly more viable. I will readily admit that stroking to add cubes makes total sense for the street and even serious competition if built right. The stroker obviously makes more torque. The 377 would be slower to probably 4,500 RPM, depending on the specifics of the build.

Where the 377 shines is at high revs where its maximized R/S ratio increases stability and upper cylinder dwell time. The 377 only outruns the 383 when built to make power past 7,000. Only, a nut would spend what it costs me to build this engine the right way, for anything other than serious long course racing. Especially for a car that will never see serious competition. Unfortunately, I am such a nut. I love the traits of the 377 that much. Of course, unless my wife lets me spend the money, it aint gonna happen in this lifetime anyway. LOL

 

I built a 377 years ago and I was very happy with how it ran. I used the 400 bearing shells line bored out to accept 350 bearing shells with the 5.7" 350 length rods and it worked well. It was a very cost effective way to get more cubes. If you used the "proper" spacer bearings the cost was much higher and made it much less attractive. But the low buck way worked out just fine, even though I was a little leary at first.
One of the main reasons we did it back then was to get away from the bigger, heavier, externally balanced 400 harmonic balancer and the need for external balance on the flywheel.

I had the engine in the car for the season championship at the end of the year. At the time I was beating a guy from the other end of town pretty regularly (dirt circle track). His Father was getting pretty hot under the collar about getting beat so much and built a new engine to try and beat me, and everybody else.
We had the same machinist, and he would massage my stock rods and parts making sure they were totally straight and absolutely round, do rough two step pocket porting on my factory high performance heads which I would then finish out, and use mainly stock stuff keeping the costs down. I would end up with around $1800-2200 in labor and parts in my engine not counting carb and headers and such.

The other guy's Dad told the machinist to order some good heads and ended spending about $5000 on their long block.

We ended up starting the Championship Feature side by side, and I pulled him about 4 car lengths from just before the green flag and start/finish line on down to the braking point for the first turn. Man that guy's Father was mad!
I think they were running a 355, but man it was still fun!

One thing, no matter what combo I was using- 400, 383, or 377, I would always use at least 5.7" long rods rather than the shorter, stock lenghth 5.65" 400 rods. I've yet to pull a 400 core apart that didn't have a lot more cylinder wall scuffing/wear than a comparable 350.

 

Other than the smaller bore dia., nothing really. It'll limit the size of valve and lift you can run. But with some standard 1.94/1.5 valves, you can probably run a decent sized cam and make some power with it. Obviously not really worth completely rebuilding, but if the current shortblock is OK, you could run with it. When you go to build it up, if the crank journals are still sevicable, you could probably just get by with tossing some fresh cam and crank/rod bearings in it and call it a day.

Although the last few 305's I had where completely sludged out and trashed bayond even a full rebuild. The older oils didnt perform as well as what we have now. Not to mention that most people dont bother to change it on time.

 

The valve shrouding is more of a speed bump then a road block. It is such a common misconception.

Lightweight 8mm LS 2.00, 1.55, valves are perfect for a 305 screamer.

There's even a guy on TGO running 2.02in, 1.6ex, valves @ .550 lift in a 305.

 

Wonder how close those get to the cylinder wall?

The 305 has a smaller bore, so IMO it kinda negates the need for large valves. Might even flow more if there is more clearance around the valve. Might be something interesting to look into on a flow bench.

 

Here's 1.94/1.50s in a .030 over 305:

 

2.02/1.6 looks like theyd get pretty close to the cyl. bore.

BTW, engines got splayed main caps, what are you planning on doing with it?

 

Not my engine. For the sake of civility I'll pretend you didn't just suggest I'd be silly enough to waste time and effort putting splayed caps on a 305.

In any case, this is what happens when you put a 2.02 valve into a 601 head.

 

David Kauffung's 305;


My Junk;

 

ok that one i get really well (305 not worth the trouble)

 

David Kauffung's 305 made 400hp in 2007 at the Engine Masters Challenge, and 487hp in 2008 at the event and was DQ for an illegal oil pan.

Both had stock crank and rods with hyper pistons.

Yea, it's so not worth it.

Getting the most of what you have makes more sense then wasting money making a 400ci slower.