midyearguy

Looking at rebuilding my 327 and want to know how much HP I can get from it and how? Also if I built a 350 or 383 how high can I go and how would I do it? Thanks

396 RAT

How long do you want it to last?

62fuelie

More importantly, how much money do you wan to spend? A 327 can be made to put out a lot of ponies, as can a 350 or 383. Speed costs money, how fast do you want to go?

396 RAT

Time tested bolt on "easy items" include
Intake Manifold, Carb, Headers- exhaust, Ignition work (dist).
Good for an easy 50-75+ hp improvement over a base engine.

Next step would be Cam, Heads, Compression & ballancing.

In your case, The best bang for the buck may be a GM Crate engine.

As far as the most possible, 1000hp is not at all out of the question.
Just wont be very streetable, and wont last very long.
You can buy or build an easy 350-400 hp small block that should last for quite some time.
All this is just my opinion.......
:flag

L79vette

Unless you want the car to appear stock and have the correct casting numbers, etc., just build a 383 or a 406.

I'm seriously considering the 406. My 327 runs very nice, and puts out 20+% more power than stock, but the low RPM kick of more cubic inches is calling me.

SWCDuke

Select a cam to yield the low end 80 percent torque bandwidth at no more than 2000-2200 RPM and spend to the limit of your budget on the heads, inlet, and exhaust system to get peak power.

My recommendation is to stick with the L-79 cam or upgrade to the LT-1 mechanical lifter cam (more peak power, almost no loss of low end torque), and everything else on the engine alone using the original or OEM replacement parts, but have the heads/manifolds professionally reworked with a street pocket port, port match, and three angle valve job. Spend your budget on the heads, not on hot rod parts.

Carefully blueprint the engine paying particular attention to piston deck clearance and shoot for a static CR of about 10.5:1, which should allow it to operate on pump premium with a little timing map juggling.

Duke

396 RAT

:iagree:
But the question was "What's the most HP possible from a 327?"
Kind of a silly question.
If its the orig L79, and more power is required, I
would recommend putting it on a shelf and buying
a performance Crate engine & go from there.
Lots to choose from.....
Duke, your advice would make a really sweet street set up.
But I am not sure if this guy wants 400hp?? or 4000hp? :lol:

63Corvette

I agree that if you are not limited by rules (or money) go to a larger engine (383 etc.) I race a 3050 lb 63 coupe SVRA. When I ran a .030 over 350 with a 754 cam, I made about 450 hp and the car was very drivable. I still drove it on the street (but I have 4.11 gears, and Duke is correct that this is too much cam for a street engine).
However, when the rules required that I run a 327 (+.030), and got it to develop the same horsepower, It was no longer drivable on the street, but was almost undrivable on the track! It lost too much "area under the curve". That is, the horsepower and torque curve steepened and narrowed up. You definitely don't want this type of engine for the street. You DO want an engine with broad, usable torque curve across the widest rev range regardless of peak HP. You get this with cubic inches. Use the best quality parts you can afford. Horsepower comes from the cylinder head, the torque band comes from the cam.

midyearguy

Guess I was a bit vague there. :) Looking for around 500-600HP, car is pretty much a daily driver. Also want lots of torque on the low end. Another question is how much will sidepipes affect things?

0X-AutoProducts

at that output level, a 327 wouldn't last long. better go with a BB crate motor.
also, at that level, what will you do for brakes, cooling, tranny, etc, etc, etc.

Mel Foye

500-600 and daily driver. With a 327. Through the mufflers. And street legal. We run a 550 hp small block and to try to drive on the street on a regular basis is just not going to happen at those #s. Time to decide if you want a solid running street car or bs bragging rights?

Kid_Again

...have you bought 327 replacement parts recently?....they cost a fortune...if you want to build a small block, go with a crate motor as noted previously.....

...probably the best answer you received was "how long do you want it to last?"....12:1, long duration cam. supercharger, nitrous, worked heads and dual quads?....1200 hp for a few minutes

SWCDuke

You're day dreaming!

My hunch is that you know little about engine system engineering. There are a lot of good books out there like how to rebuild your SB chevy and how to hot rod your SB chevy from HP books. You're best course of action is to spend fifty to a hundred bucks on books and get yourself an education before you start throwing money away to build a "daily driver 500-600 HP 327 that has lots of low end torque".

Not even the late Smokey Yunick could do this! For maybe $20-30K including lots of development work and dyno time you could build a 327 using virtually all aftermarket parts with this kind of power at 8000-9000 RPM with open exhaust, but it would be undriveable on the street, not to mention illegal due to the noise and barely idle at 2000 RPM. You're talking about a narrowly focused pure racing engine.

A carefully engineered and built street driveable vintage 327 with a decent 80 percent torque bandwidth will make about 275 HP at the rear wheels, 300 tops. Try to go beyond this and the flexibility of the engine degrades to the point where streetability goes out the window.

In order to engineer a decent street high performance engine you need to think about cold start and cold driveability, idle and low speed driveability, throttle response, the shape/useability of the torque curve just to name a few. You need to understand the air-fuel ratio and ignition advance requirements for all engine operating conditions and how to achieve them in the real world.

System engineering a good street engine is a lot harder and requires more development than a racing engine because you have to be concerned with the entire operating range from idle through part throttle to WOT at peak revs, rather than just the WOT power in the top 25-30 percent of the rev range. The L-79 was a very well engineered engine and is a good place to start, and for not a whole lot more than a major rebuild you can build a useable 275 to 300 RWHP street engine using the tips I gave in my prior post and careful attention to assembly detail.

Duke

midyearguy

I never said I was a system engineer. I guess the question I should have asked was how much HP I could get out of a 327 or another small block and still have a daily driver out of it? Can anyone help?

Mel Foye

Put that way I would say about 350 hp at todays ratings would be close to the max on a 327. Should give you hp, long life and decent low end. To me a daily driver can go on 6-9,000 mile trips. Not everyone will have that defination. My personal daily driver is a 57 Chev, 350 with about 275-300 hp. Decent gas mileage, can idle for hours, spins the tires, never over heats etc. To me the best balance is a mild motor, stiff rear end gears and a 700R4. Mel

396 RAT

In my opinion, HP from a short stroke 327 comes at high rpm.
(over 4000 to maybe 7000)
Not gobs of torque, but a nice high winding engine.
A 350 on the other hand, can turn into a 383 and have gobs of
torque, but peter out below 5500 rpm.
Sounds to me like you are looking for a long stroke engine
rather than the spin it up 327.
I like just the opposite.
I suggest buying one complete from one of several vendors.
Should cost about as much as pumping up your tired 327.

Vetterodder

:iagree:
With low enough gears, you could probably have decent street manners with more than that but highway cruising might not be too pleasant. Also, cold starts, tuning, and reliablity issues are important considerations. According to Desktop dyno, my .030 over 327 makes 410 gross hp @ 6,000. It's drivability is excellent but I believe that it's near it's limits. Most anything that I could do to make more power out of my current displacement, other than supercharging, would likely result in a car that is less enjoyable to own and drive. As the others have said, go for more cubes if you want more power. More cubes will give you more power throughout the powerband and do so without revving it into the "danger zone".

L79vette

You can build a nice driveable 327 that puts 275-300HP to the wheels, and then add nitrous to it for a real kick in the shorts when you want it. If you plan ahead you could run a 200HP shot, maybe even 250HP. Things will definitely start breaking in the drivetrain.

But again, "there is no replacement for displacement". A big motor will be much more enjoyable to drive, roast the tires at will, and no filling the bottle. And as long as it fits in the small-block form factor, you've got no weight penalty either. Gas mileage yes, but that really does not matter for a toy.

garagedweller2

Well, go for a crate 350/383/406 since you don't want to spin up your engine!

SWCDuke

If you want to build a streetable high performance small block you will be best served to learn something about it.

Duke