66BlkBB

Not necessarily on a budget. Right now I just want to weigh which would be better for the car and me. The build for both engines should be about the same, give or take. I am planning on taking the 32 apart next spring so I can complete some of the under carriage work. I also have some work on the body so it may take a while to get everything done. Would be looking to rebuild the engine at the same time so I can get it all put together in a reasonable time frame.

Jims66

Shorter stroke in the 327 (3.25 vice 3.48 ??)

MikeM

Can you tell me how that works?

Glasshole

When I bought my 63' it had a 350 in it. The original 360hp 327 engine also came with it. I drove it with the 350 for about a year. I have since done a frame off and put the original 327 back in. I prefer the 327 hands down. The solid lifter 327 revs higher and faster, sounds better and is far more period correct. IMO

Jims66

http://www.badasscars.com/index.cfm/...d=90/prd90.htm

MikeM

The valve train is usually the limiting factor in the rpm limit of an engine. Not the stroke.

My question said "common valvetrain". I didn't say anything about "power", either.

MikeM

And you attribute that to what? Cubic inches? Stroke? Or camshaft?

Glasshole

I attribute that to smaller displacement, shorter stroke and a solid lifter valve train.

NOM61

The shorter stroke by itself doesn't necessarily make the engine rev higher.
It simply reduces the stresses on the rotating assembly at a given rpm level, making it less detrimental to the rotating assembly to rev higher for longer periods.
The longer the stroke the greater the acceleration forces at a given rpm since the piston has to travel a greater distance in the exact same amount of time as a shorter stroke engine.

But... it does make it rev faster...
Two engines at TDC. One has 3.5 inch stroke. Other has 3.0 inch stroke. Both cylinders fire at same time, with same a/f ratio, scr, identical induction, etc. The pistions should accelerate at the same velocity, right?
The 3 inch stroke piston travels less distance at the same velocity so will complete its stroke first and be part way to tdc on the next firing cylinder before the 3.5 completes its first combustion stroke.

Not even considering all the other factors such as lateral forces, etc.

DT

MikeM

Thanks but here was the original question from post #11:

"One of you from the "High Winders" club please explain to me how a 327 is going to wind up any higher than a 350, given the same valve train"?

That question hasn't been answered yet.

mrg

From the badasscars article:
Given a stock engine buildup and without doing the math and/or knowing where the limit is on a reasonably safe piston speed: .. If a 350 tops out at say, 6500 rpm, where might that same piston speed be reached in a shorter stroke 327.........7000 rpm? ..

Some here on the forum have said their 30/30 cammed 327's have spun to 7000+ with ease. Not to take anything away from a 350 build with its better torque, etc. .. Besides, everybody 'has one'.

Glasshole

I would think the 350 has greater reciprocating mass than the 327 causing it to self destruct due to high RPM's before a 327 would at the same RPM's.

Besides that, a 350 is a truck engine..........LOL.

NOM61

Easy.
Since you didn't specify the valve train, only that they are the same, I'm going to assume the valve train is designed for 8K rpm.
Also assuming identical induction/exhaust/cams capable of 8K. (not specified in your question either)
The 350 is going to pull apart due to the higher velocities, acceleration, etc at a given rpm inherant in the longer stroke well before the 327.
Run them both up to 7k and keep them there.
The 350 breaks first.
Hence higher sustainable AND attainable rpm with the same albiet well endowed, valve trains!

DT

mrg

My oops .. Think I got it backwards. . .

NOM61

No. You got it right.
Think of it as total distance traveled by the piston.
Take a simple equation:
(3.5 in x 6500)/3.0 = 7583
So the 327 will achieve the same velocity at 7583 rpm as the 350 does at 6500 rpm.

DT

MikeM

Neither one of them are going to "pull apart" at 8K assuming proper parts are used.

There is a myth that the 327 will wind up higher than a 350. That ain't the case and it has nothing to do with stroke or piston speed assuming you are talking about a street engine. That is what we're talking about isn't it?

A street engine speed is typically limited by the valve train whether it be solid or hydraulic lifters.

If you think a 3 1/2" stroke won't wind up tight, witness the Nascar engines that run close to 10K rpm for laps on end and yes, they'd probably rev higher but the valve gear would fail.

robert miller

a well done 383 is really hard to bet..... Then you can tell ever one it is just a cam and stock 327. Make sure you get some good heads on the car.

street62

A 350 is a better street engine, the power band will be at a lower rpm where most use it, stop light to stop light. I would allways want to build more mid range power, that is were the engine spends most of its time in any kind of street race,very little at high rpm .

Glasshole

Well if you have the 4.11 rear gears and the close ratio 4 speed like I have you tend to spend a lot of the time in the upper end of the range.....

NOM61

Real world? Nascar? Theoretical? What are we talking here Mike? This is all over the place.
If you want to talk "real world" or "the street", then the only thing that matters is cubes since most street engines never see more than 5K and even the most rediculous stroker will handle that just fine.
Nascar? You can do anything if you have enough money to throw at it, and they surely do.
How about this case:
Take two identical "budget" 350's on test stands. Run engine 1 at 8000 rpm. Run engine number 2 at 7430 rpm. Which engine will fail first?
That's the same as if you ran an identically built 327 at 8k.
I reflexively ran the earlier calcs using the 302/283 stroke instead of the 327. Make engine 3 a 302 and it would have the same stress as a 350 running at 6857. 6857 vs 8000. Identical components. Who breaks first?
And you can definitely make the same rpm cheaper with a short stroke. The physics doesn't lie.
In the end, we don't build short stroke motors to run at max rpms. We build them because they COULD, and because we like the free revving feel those engines have compared to a longer stroke. For the same throttle input/air-fuel ratio, that short stroke is definitely going to reach a given rpm faster than the long stroke.
In the end, its all good.
This world has plenty of room for BB guys, stroker guys, AND spinner guys.