I know this question's been done to death. I've been reading hundreds of threads lately, looking for keywords like "zz502", "procharger", etc. Just trying to get some real world opinion. The problem is, there's probably not many folks who have done BOTH. More like, some go one route, and some go the other route, and never the twain shall meet

Is there really a difference, or is it a question with so many factors that a true answer can't be arrived at? The big block is heavier (generally) than the small block BUT a centrifugal blower might be a pain in the *** in a C3 and a roots style would involve cutting the hood and compression ratio would have to be reduced and on and on the decision tree goes...

It just seems like with artificial boost, one achieves the same effect as larger pistons/cylinders. Unless I'm missing something? Wouldn't the BB be more rigid and able to cope with 800+ hp?

Just thinking out loud here.

 

yep, you can build a N/A Big block to pump out 700 hp on pump gas with the right combination, and do it pretty reliably.

 

I dont have an answer for you, but by the time you add a supercharger
to the small block, it will weigh just about the same as a big block.

 

Something else to consider. With forced induction (supercharger, turbo's) you need to use a cam that has very little/no overlap. This means the engine can be made to run very smoothly at idle/low engine rpm. If you're trying to get Hp with a normally aspirated engine, you have to have a cam that has a very large overlap duration and hence a very rough idle.

 

Good advice, in addition to that: Consider that forced induction carburated engines become much more sensative to atmospheric conditions than n/a motors (air temp, humidity, elevation, ect.). Basically forced induction "fools" your engine in to thinking it has a larger displacement. You are increasing the density of the air-fuel charge coming in to the cylinder. This will yield a greater energy output from combustion by cylinder volume when compared to normal aspiration. In other words, you are cramming more air and fuel atoms in to the same space as the n/a motor, making a bigger explosion!

With a forced induction small block you will also have less weight when compared to a normally aspirated big block. This lower weight will affect acceleration and braking positively but cornering will be affected negatively (less force applied in the direction perpendicular to the tire's friction coeficient).

So ask your self 1) Do I like twisty roads and track days? 2) When I drive, will I be changing elevation, going to more or less humid places? 3) Do I only want to go as fast as possible (reliably) in a straight line?

Just some food for thought, hope it helps.

Kelly

 

I'm running a NA 427 and a turbo 355. Pros and cons for both.

The 427 is easy to modify and tune. Very few unknowns running a normally aspirated (bigblock) engine. Main downside is the weight, if handling and braking is important to you.
The 355 runs like stink and the lighter weight sure helps on road courses. As 68/70 mentioned above, it also idles like a Cadillac, thanks to the turbo cam. The downside is it is harder and more time consuming to tune a supercharged/turbocharged engine, and melting a piston is always in the back of your mind every time you turn up the wick.

 

Another upside to forced induction: Uniqueness. Your engine bay won't look like every other Corvette of that model year.

 

I think I have found a happy compromise in the GMPP ZZ383 crate motor. BB power, SB weight. Crate motor reliablility with factory warranty. that's my $ .02

 

Small block weight 575 lbs + supercharger kit weight 100 lbs = 675 lbs
Big block 454 weight = 675 lbs
Where is the weight difference?

 

If You Go With Aluminum Heads, Intale Etc. You Can Knock About 100 Lbs. Off The Big Block

 

If you plan to drive long distances like Power Tour, a blown small block can be built and tuned to give MUCH better mileage than a big block. I saw a big '50s station wagon pull over 20 mpg supercharged on a tour, and your 'Vette should be at least a thousand pounds lighter.

As for the engine weight factor, the car I refer to was twin-turboed, probably less added weight than a Rootes-type blower.

 

You must be talking about one of the big roots type of blowers that pop a sunroof in your hood because I can't imagine one of the compact centrifugal set ups weighing anywhere near 100 lbs.......]

Either way, super chargers are

I just attended a big car show in Beckley, WV this last weekend and saw several blower setups.....very nice! The news reported nearly 800 cars were on display. I was a little disappointed in the C3 turnout though. I don't remember seeing a single chrome bumper C3 there at all. Oh well, that makes it better for me once I get my '69 done and in shape to enter it. There were tons of late 60's Camaros though.

 

Also; I have owned big and small blocks the big boys are faster. I have not had a supercharged small block though. I have had turbocharged aircraft and the FAA will reduce the time between overhaul by about one third for turbo verses natural aspirated engines. That tells me the natural aspirated engine is more reliable and longer lasting. I would assume the same would apply to auto engines. Or maby not? Not an engineer, just a jocky.

 

Roots blown smallblock here...makes unruly amounts of torque right off idle. I look like this every time I fire it up

 

Lots to recommend both. A big block will likely be more reliable long term and easier to work on. A small block with a blower will give you smooth running and better handling and braking (everything being equal). Both will make you feel like John Holmes at a cruise-in with the hood up for all to see.

Now if you want real wow factor and performance, drop an LS1, LS2 or LS3 in the car with a Vortech blower set-up. That will give you make you feel like John Holmes on Viagra!

 

Hey man......not hyjacking, but where did you get your logo or who did it ?

 

If you're talking about my avatar, it's from a t-shirt vendor on eBay...

 

I can answer this one for you,ive had both and there is no comparision between NA and supercharged,supercharged wins by a long shot Like yellow72 said,you will have a smile on your face everytime you get in the car and drive.Those who venture an opinion and have never had a supercharged car should not even comment.Sorry but its true Totally wrong about being drivable on the street supercharged car can be and is just as reliable and it does have as good or better street manners The 100 pound thing,NO WAY BRO,maybe a 100 pounds with a 871 blower,but i dont think so.Remember there are street blower too guys,that give a 100 hp just bolting them up.And a centrifical blower is 20,30 pounds,take or give a few.Heres a pic of both my vehicles,centrifical and roots type blowers.They made such an impression on me,all my vehicles are supercharged,its the only way to go. The seat of the pants feel you get will blow you away,nothing like it.Also i built my engine in the corvette when i first got it three times over a couple years ,making it bigger and bigger and bigger ,i was never satisfied with what i got,so i guy that raced cars that i worked with told me just stop building and go supercharged,i would never be happy until i did,so i got some extra money one year and went for it,that guy at work was not kidding,i will never have any car or truck of mine without being supercharged.I had big block pontiacs and built them and always wanted more hp.blower or turbo all the way.

 

Now, I got a t70 turbo in my garage and it isn't real heavy but I would guess 30-35 lbs, add 1 more with carb bonnet, blowoff valve, wastegate and intercooler/tubing I would guess they would be similiar........ Also, with the BB heads available and the displacements attainable one doesnt need to run a huge cam to make big power. That being said, for the street a 400ci smallblock with roller cam and good heads is plenty reliable and powerful????

 

There isn't a definitive answer to this topic.
It will always come back to what you want and how much you are prepared to spend.

Do you want a drag car, a circuit racer, a nimble hill climber, a show car, a boulevard ear and eye candy cruiser or a long range cross country tourer....
or like many of us..... various combinations of all of the above.
And that's the catch. Finding the compromise for your needs.

Personally, I have found my nirvana with a stout stroked normally aspirated small block. Is it enough?..... for what I do with it .... yes!

I can check most of the boxes in that list above now that I've also fitted an overdrive tranny. It won't win any outright competitions against dedicated race cars or show cars, but it satisfies my needs to participate in a variety of driving events and have fun.