I was originally planning on building a 400, but I have since heard some good things about the 327's.


A friend of my dads has a bunch of 327 motors, for some reason he bought every 327 he came across.


Anyways, I was just wondering if some of you could tell me the best way to build up a nice strong 327. Also should I bore it out?? If so how much.


But yea, a list of heads, cam, intake pistons, etc..... would be great.


Thanks

 

It's a 4" bore small block. Anything that works well in a 350 will work well; about 93.4% as well as it would work in a 350 to be exact.

How far you can bore it depends on what block you have. They're a 4" bore block, some of them are the same block casting as 350s of the same year.

Just think of a 327 as a 350 that's missing about 7% of itself, and go from there.

 

I know..... You could make it a 327 stroker motor.

People would look at you funny when you say that, but just tell them it's a 327 you bored over and stroked to a 355.

They'll think you're some kind of engine building guru. :sillylol:

 

how would i do that?

 

Put a 350 crank in it and bore it .030"

 

what about heads, cam, intake, carb, rods, pistons, etc........

 

Heads are the same (will work with either).

Cam is the same (as long as it matches the RPM band that you want, and the heads)

Intake is the same (should match the RPM range of the cam and heads)

Carb is the same (should be adjusted for the larger displacement by re-jetting, when the secondaries come in, etc.)

Rods are the same. (Same length, material, etc.)

Pistons do have a different compression height (distance from the center of the wrist pin to the face of the piston), but when you buy a rebuild kit, just specify that to the people you're buying it from and they'll be sure to give you the correct ones.

Other than that, that's about it.

It's not that the 327 is a bad engine. But it is "retro". It's cool to say you have a '66 Nova with a 327, but for modern power, the 350 is hard to beat (both at the track, and in the wallet).

 

I kinda prefer the 327 to the 350.... yea, they have very slightly less power potential to a 350, but I like high winding engines.... Thats why I love the Z/28 302 so much... would have been good for 8000 rpms from the factory if the ignition could keep up

 

The information you might be missing that no one has appeared to make clear is that the 327 large journal block and the 350 block are demensionally exactly the same. Only the crank and piston compression height is different. The crank is a 3.25" stroke and the 350 crank is a 3.48" stroke. The pistons must accomodate this shorter stroke so the distance from the pin to the top of the piston (compression height) is longer to make up this distance. Otherwise your piston would be way down in the bore at the top of the stroke. So you simply put a 350 crank and pistons in a large journal 327 and you have 350. The same heads that work on a 350 will work on a 327 but stay with the 58cc (aluminum L98) to 64cc combustion chambers to keep your compression up with flat top pistons. Vortec heads would be a great choice, if you can afford the manifold that must go with it. The combination would be about $650 -$700 new and will flow much better than the camel back heads that came on a lot of 327's. Good luck!

 

Only '68 and '69 327's were large journal. If your friend's dad bought up every 327 he came across, most likely 80% of them are small journal.

High-winding 302's and 327's are about the biggest myth out there. It takes the same things to get a 302 or 327 to wind up as it takes to get a 350 to wind up. How do I know? Because I've had 283's, a 302, 305's, 327's, 350's and 400's. I have a racer buddy that has a 383 (same stroke as a 400) that winds up higher than any of the engines I've had (except the Honda 550, which wasn't listed above ).

You first have to decide how you want this engine to act. Then, you pick a "package" of cam, heads, intake, & carb to do that. Compression is a small player in all that, except being able to control detonation in its intended use with the available fuels. The fact that it's a 327 rather than a 350 doesn't make any practical difference in the choices of those parts.

Boring the cylinders is only an issue in "clean-up". If the cylinders are worn, tapered, or scored, bore it to the next oversize and buy pistons and rings to match.

 

Yes, a longer stroke engine (ie. 350) can wind up just as well as a short stroke engine (ie. 302) BUT the engine with less stroke is going through ALOT less inertial stress than the engine with the long stroke. Thats the reason that short stroke engines like the 302 typically have a higher redline that a longer stroke like a 350. Its because it is safer for the engine to wind a 302 up to 8000 rpms than it is for a similar 350 to wind up to 8000 rpms because the shorter stroke put far less stress on the engine. Thats partly the reason that in the '60s, the usual Hi-Perf 350 like you'd find in a Camaro or a Corvette usually had a redline around 5000 rpms, but from the factory, the '69 Z/28, which had a 302, had a redline somewere in between 6000 and 6500 rpms. This is probably were the 'myth' spawned, but it isn't entirely untrue either.

Five7 is right though... the difference between a 327 and a 350 is not much.

 

It isn't a mythe. A shorter stroke as in a 327 for example makes each piston's stroke roughly .25 inches less than in a 350. That is approximatley 2 inches less over all 8 cylinders and when an engine is running at 5000 revolutions per minute that can make a big difference. What i am getting at is that is you have a 327 with 300 hp and a 350 with 300 hp the 327 will walk the 350 every time.

 

IROC355,
This opens up a whole new can of worms. You need to choose what you intend to do with your car. Is horsepower your goal....or is torque? 327's do well on the drag strip where you can make some high winding horsepower but if you using your car primarily on the street, build an engine that will make lots of torque like a 350, 383 or even a 400. The third generation F cars are no light weights and need a good amount of torque to get them going. It is one big reason the 5.0 can hang with them. The F cars give up about 400 lbs to a 5.0. You are saddled with that weight everytime you leave a stoplight or come to a stop for any reason. It is torque that gets the car going in those situations. If you are using the car on the strip, then you use a 327, raise the compression to the moon, run a honking big cam and build the car for high rpm use where it'll make the maximum of horsepower.

 

Some of you are SOOOO misinformed. *AJ sighs*

What's meant by a 327 being a "higher winding" engine is that it needs to rev higher than a 350 in order to make more HP than a 350.

A while ago I made a chart using DD2000. I know DD2000 isn't exactly accurate all the time, but when only comparing the two stroke differences for power output, it's VERY accurate.

Here it is again...

The 327 is the dotted lines.

As you can see, it's not so much as WANTING a high reving 327. It's a matter of HAVING to have one.

 

I think not.

No, that's not correct: I know not.

AJ, not to be contrary, but all other things being equal between a 327 and 350 (cam, port flow, induction, exhaust, etc.), do you really think they would have the same torque and HP at 5000 RPMs? No, I don't either. Something about the combo you imputted made that happen. Or, DD just isn't making the grade.

Note that even in AJ's example, the area under the curve up to peak torque/peak HP is greater for the 350. Therefore, assuming the engine doesn't operate only at peak torque or peak HP, the 350 will pull the same mass up to peak torque/HP quicker than the 327 will.

I understand the internal stresses will be lessened in the 327 vs. the 350. That doesn't change what happens to whatever the engines are twisting.

 

Keep in mind that all of that area to the right of each motor's HP peak is unusable, since for the car to go the fastest you shift at peak HP.

All you younger guys with this "short stroke wind it to the moon" attitude must think that you are the first people ever to grace the face of this planet that have ever dreamed that up. Well, as a geezer that's seen alot of them come and go, I'll tell you, it ain't so. Back in the 70s, when the 350 became widely available for us to build, we all quit building 327s, for one simple reason: they lost!!! Anything you can do to a 327 (or a 283, or a 302), you can also do to a 350; except that when you do it to a 350, you get more. The 69 302 vs the 70½ 350 are a perfect case in point: the 302 ("rated" at 290 HP) was probably capable of about 325 HP; the absolutely identical motor in every way the next year — same block, same heads, same rods, same cam, same intake, same carb, same exhaust, same transmissions, same gears, everything the same except the crank and the piston deck height — put out about 375 HP. A 327 would fall right in the middle. How can anyone possibly argue with this simple observed reality?

You don't just stick a short stroke crank in a block and suddenly re-invent the internal combustion engine. If you want to build a 327 or 302 or whatever that will beat a 350, you will have to concern yourself with valve train components that have to be set up for high RPM, a camshaft profile that raises the peak RPM band, a shorter set of gears, etc. etc.; and still, if the guy in the next lane does the same thing to his 350, he will beat you!!!! The rules of physics in this universe haven't been changing since 1973, you can believe that.

So sure, you can build a 327 that will beat some 350s. It will cost you more to build that 327 than it will to build a 350. You can also spend the same amount of money on a 350 and beat the 327. You can spend less money on a 350 and get more power then you can out of a 327, and it will be more reliable. Any way you slice it, the 327 will lose.

But don't believe a word I say. Go do it. It's your money.

 

I'm contrary to you being contrary. (I.E. you aren't )

The DD2000 automatically figures a lot of variables like BMEP, IMEP, FMEP, and Volumetric Efficiency %. There is also only a "small tube header" or "large tube header" portion that automatically figures in anything less than XXX% of exhaust port size. I'm guessing it assumes this on volumetric combustion from the shorter stroke, static compression, and cylinder pressure in order to figure what that % would be.

Plus you gotta remember... what's considered an aggressive cam in a 327 is more tame in a 350. In order to "help" the 327, I purposely left the cams the same. If I were to input a cam that's equivilent to the one in the 327, the 350 would REALLY make the 327 look bad.

So no, they may not meet at the EXACT RPM that DD2000 calculates, but I'll bet it's darn close (within 500 RPM).

And as you said, it's regardless. The real thing to look at (as RB pointed out) is, even though the peak HP is higher, it's also at a higher RPM. It's kind of like them import boys that say they have 250HP. Well that's not difficult to do if you raise the peak HP to 8000 RPMs with a smaller motor (kinda like the 327 is smaller than the 350) instead of 5500 RPMs like a SBC 350. What's harder is to keep the RPM range high enough in the shift points to keep the torque high. According to that chart, the only way to do that is to keep the shift points ABOVE peak TQ. That's kinda Bass Ackwards, don't ya think?

 

First of all me being younger doesn't have anything to do with it. Second just because i am younger and probably mentally inferior to your almighty self :hail: doesn't mean that you have to talk down to me or argue with me. I would like your imput but i am not arguing with anyone about it. I like to read posts and gain knowledge about things i like (f-body or cars in general) so take it easy on me oldtimer. Anyway let me get this straight you are saying that a shorter stroke does not rev any quicker or make its peak hp at a higher rpm? Oh yeah one more question how is a 350 more reliable than a 327? Because if all that is different is the crank than i don't see how it is less reliable?

 

Before the edit, I accused you of using a combo to favor the 327. I didn't think that sounded very nice, so I changed it to what you see now.

And here, for once, I had it right the first time.

327bird, it isn't meant to be personal. Just informative. Some of us old farts have spent money in amounts we don't want to admit trying to prove "conventional wisdom" wrong. It just don't work. We use the 2x4 attention-getting technique to keep others from making the same mistakes.

A racer buddy of mine has a '67 Camaro 327 4-speed that he bought off the showroom floor. He had it gone over this past year, including .030" bore, 11:1 pistons, Sportsman II heads, 4.10 gears. He's .4 sec faster (on a good day) than my '57. The big difference between us is he's about 600 pounds lighter going down the track (plus the greater efficiency of the 4-speed, and the gears). With my 396 and the rest of his setup, he'd be at least a sec faster than he is now. Even if the engine didn't wind as high.

 

Assuming both are putting out the same power, the 327 is going to have to be spinning faster. That will actually increase the internal forces of stopping and starting the pistons twice a revolution to being greater than that of the 350 making the same power (you've lost the advantage of lower piston speed at the same crankshaft rotational speed).

To say nothing about what higher RPMs do to valve trains.

 

The reliability issue is real simple. HP = torque x RPM x 5252. Torque is directly proportional to the number of fuel molecules burned per crank revolution. Obviously the bigger your motor, the more fuel molecules you can burn per rev. The 350 will make more torque at any given useful RPM (as AJ's graph shows rather clearly). So it's pretty easy to draw 2 conclusions if you can rub 2 neurons together: (1) the 350 will produce more torque at any RPM than the 327 will, since it burns more fuel molecules; and (2) to achieve an equal level of HP with a higher torque level, less RPMs are required, which reduces the stress on rods, valve train parts, transmissions, etc. etc. etc.

The BS about a 327 beating a 350 of equal HP is pure uneducated, inexperienced elephant plop. Look at AJ's graph; the car that has the most area under the usable part of its torque curve (below its peak HP) will always win the race. You have to be willing to turn a blind eye to reality to claim otherwise.

I understand you don't like to be lectured to; most people don't. Believe it or not, I was actually young once upon a time too, and although I don't remember it too clearly any more, I seem to recall that fact as a feature that I hated dealing with about parents and teachers. But if you'd stop for about 10 seconds and think what you're saying before you say it, things will become plainer to understand. And you're right, being of different ages doesn't have anything to do with the facts, it only has something to do with your lack of understanding of them.

Other than the issue of it being necessary to run the motor at a higher RPM to get an equivalent HP level (which isn't enough to beat the bigger motor) there's no reliability issye with the 327. It's a damn good motor, just like the 305 is. If that was all there was we'd be happily building them. But we don't live in a vacuum; just like we build 383s today, the hot ticket in the old days was to take a 327 and build a "stroker" motor out of it by offset-grinding the crank to increase the stroke, and make a 340 out of it. Only difference is, we have .23" "stroker" cranks stock, and 3.75" stroke cranks on top of that to work with now; we're not limited to .100" undersize bearings to get the same results.

If 327s were such terrific motors as compared to the alternatives, why do you think nobody's building them today???? Think about it. I just told you why. You used to could find giant heaps of them in junkyards for next to nothing, right next to the one 350 they had that was priced about like a complete LS1 is now. I remember paying $50 for a whole running 68 Impala once, just to get the heads (to put on a 350), and throwing away the whole rest of the car at the scrap dealer (327 included) because it was worthless.

Like I said a long time ago in this post, all the parts you buy nowadays are geared toward building a 305 or 350; but if you look at how they perform on a 350, and then subtract about 6.6%, and you'll have your answer.

Arguing doesn't change reality. However, I feel obligated sometimes to point out newbie mistakes and misconceptions like there have been in this post, to keep other impressionable novices from falling into the same traps.

 

Yes you did.

I didn't even see the "before edit" of what you wrote. My typing that was simply coincidental. As I said, I did this purely on showing an apples to apples comparison. Same heads/cam/etc.

No blood, no foul.

I once thought like you both have said you did (you and RB). My first car was a (don't hit me ) '65 Merc. Comet with a 289. 4" bore with a 2.87" stroke. Talk about a SCREAMER!!! It came from the factory with a Holley 4 bbl. and a solid cam and 10.5:1 compression (back when 100+ octane was readily available). I thought I was the **** because I could whip any new (1987) TA, Camaro, Monte SS, and Mustang I came across.

I was a firm believer in short stroke motors UNTIL I came across a 383 in a '73 Camaro. He handed me my butt in two seperate pieces :lala:

I don't think that way no mo'. :nono: I've been a 350 Cheby man ever since.

 

Basically to summerize everything said here, a bigger displacement engine, aka 350 vs 327 will make more power if reved to the same rpm. But the 327 has the shorter stroke making the internal stress of reving it so high less because the piston does not have to travel as fast. So if u are gonna build a motor to spin up to 8000 say for road racing or high performance use, either use a smaller stroke 327 or use very strong parts in your 350. But generally if u are spinning a 327 safely up to there u almost are spending the same to run the 350 up to there, so it usally isn't wasting the extra displacement, and torque.

 

[QUOTE]

A while ago I made a chart using DD2000. I know DD2000 isn't exactly accurate all the time, but when only comparing the two stroke differences for power output, it's VERY accurate.

Did your DD2000 program take into account rod to stroke ratio. The fact that a 327 has a more favorable rod to stroke ratio (1.63 for the 350, 1.75 for the 327) might be another factor in the ability to create more rpm from a 327. The higher the rod to stroke ratio the less friction created by piston side wall thrust. This friction would lower the 350's ability to rev in comparison to the 327. Not by much but the phenomenon is still present. You might notice that all Winston Cup NASCAR teams will run a longer rod (raising the rod/stroke ratio) when competing on superspeedways as compared to the rod length when running short track. Most of this is for power placement within a powerband but some of it is to increase rpm capability.

 

The thing about NASCAR isn't entirely correct....

You may notice that they run higher RPMs on the short tracks than they do on the big speedways. First off, on the 2 biggest ones, they run restrictor plates, and the motors only turn 6500 or so. Second, the number of revolutions over the course of a race is what ultimately determines the lifetime of an engine; so at Martinsville, the shortest track on the circuit, they also run the highest RPMs; well over 9000. Think about it.... ½ mile, 500 laps (250 miles total), less than half the time accelerating and the rest of the time braking and coasting around corners at 5500 RPM. Whereas at a fast track like Michigan or Altlanta, it's 500 miles with the motor much closer to max RPM all the time, so they can't run those high revs. They usually gear the cars to run 85-8600 on tracks like those.

They run the longest rod they can, all the time. They also run a 4.155" bore and 3.31" stroke.

None of this has anything to do with whether it will make the slightest difference, for better or for worse, in your street car.

I'll still stand by my original statement, after all the BS is identified. A 327 is just a 350 minus a few of its cubic inches. Any combination that works well in a 350 will work well in a 327; about 93½% as well, to be exact. That's why, in the early 70s, I abandoned 327s; 350s are simply faster, period. It didn't take real long of getting smoked to figure it out. There is no possible way to make a 327 beat a 350 for an equal expenditure of dollars, or using identical parts, or under any other similar circumstances. The 350 will beat the 327, every time, no further debate, period. The only way to make the 327 beat the 350 is to handicap the 350 somehow.

Personally, I will never build a 327 again, at least nt with the specific intent of getting the most power out of my dollar. It costs the same to build either one.

Let's imagine you're going to the grocery store, you're going to buy something.... a bottle of detergent let's say. You walk up to the shelf, and there you see 2 bottles of detergent. Same brand, same price, same everything; except, one bottle has 32.7 ounces in it, and one bottle has 35.0 ounces in it. Remember, they both cost the same. How long does it take you to make up your mind which one to buy?


....




How is a motor any different? You gotta be some kind of moron, or wearing blinders, or just be a glutton for punishment, to think that an otherwise identical smaller motor is going to outrun the bigger one.

 

What I meant my saying I loved high winding 327s and 302s is this:

First off, I wanna say this. I know that a 350 built identically to a 327 or a 302 will make more power. Lots more. Period.

Now that that is cleared up...

What I mean about liking high winding engines like the 302 and 327 is that, unlike most long stroke motors like a 350, 383 or 400, a short stroker like a 302 will make more power upstairs. What I mean is this: Look at the '69 Z/28 (302) and the '70 LT-1 (350). They are identically built motors except for their stroke. I found, in an old car magazine of my dad's, a dyno comparison of these two engines, totally stock. The 302 made 345hp and the 350 made 370.

Yes, the 350 did make more power, BUT the 350's horsepower topped out at 5000 rpm. The 302, however, peaked at 6500 rpm.

I may have been mis-understood about what I said before. What I said above about the 302 peaking much higher than the 350 did is what I like about short stroke engines. They may make a little less power, depending on the build, but it can wind up alot higher without running out of steam like the bigger engine would.

THAT is why I like the 302 so much, and prefer it to the 350.

 

RB83L69,
I really can't comment on your NASCAR explaination. I got my information from NASCAR GARAGE, a weekly television show that gets into the nuts and bolts of NASCAR tech. I really wasn't adding anything to the 350 vs 327 debate either. I was just curious to know if the program DD2000 took into account the rod/stroke ratio in it's calculation. I've done alot of research on rod/stroke ratios lately and it made sense that the decrease in side wall thrust of the 327 vs the 350 would attribute to some of it's ability to rev higher.

I personally am in the process of building a motor that takes a little from both the 350 and 327. I'm using a 400 block with a 327 or 3.25" stroke to create approximately 350 CI. I'm using 6.25" rods with off the shelf Sportsman forged pistons designed for the popular 3.75" stroke x 6" rod combo. They share the same compression height. I want to test theories expressed by great builders like Smokey Yunick and John Leginfelter in regards to the unique way high rod/stroke ratios play on the combustion process. I'm also trying to learn more about the forces of internal friction and how they play into the overall performance. I believe there is alot of "free" power to be made by decreasing these internal frictional forces.