327 Dynoruns

[Joe C.]

If I've posted this before, then please accept my apologies in advance. If not, then this may serve as inspiration for some newer members as to how much power can be developed by a normally aspirated small displacement engine while retaining a completely stock external appearance. Headers are the one concession that must be made.

The following is a 0.030" over 327 with a solid roller whose durations @ 0.050" are bracketed by the LT1 and the 30-30.

[Clark K.]

Re: 327 Dynoruns

My compliments to your Sting Ray's legendary L76 engine!
-Clark

[Peter M.]

Re: 327 Dynoruns

awesome. With the 370's and that power, bet you surprise a few folks when they look to run ya on the street!

[Philip A.]

Re: 327 Dynoruns

Joe
I also have a "65 L76. You air cleaner is '66 open paper type. Does that make any difference?

[Dennis O.]

Re: 327 Dynoruns

Is this a fresh engine? I had my '67 L79 done, and it dynoed at 336 peak HP. This is with a fairly mild hydraulic cam. I was pretty happy with those numbers, but after a couple of thousand miles, it broke in and really woke up. They must have built it real tight, because when I first got it back, it wouldn't idle for more than 5 minutes without overheating. Now I have no such problem. It would seem to me that taking a brand new fresh motor and running it to 6000 RPM after it only had 5 minutes of run time would not be a very good idea, but everybody seems to do it and get away with it.

[Joe C.]

Re: 327 Dynoruns

Joe
I also have a "65 L76. You air cleaner is '66 open paper type. Does that make any difference?

In what regard?

[Joe C.]

Re: 327 Dynoruns

Is this a fresh engine? I had my '67 L79 done, and it dynoed at 336 peak HP. This is with a fairly mild hydraulic cam. I was pretty happy with those numbers, but after a couple of thousand miles, it broke in and really woke up. They must have built it real tight, because when I first got it back, it wouldn't idle for more than 5 minutes without overheating. Now I have no such problem. It would seem to me that taking a brand new fresh motor and running it to 6000 RPM after it only had 5 minutes of run time would not be a very good idea, but everybody seems to do it and get away with it.

This engine has a couple thousand miles on it. I ran it to 7500 RPM fairly early in its life. Break in is not as important now as it was years ago.

How was your L79 dynoed? In the car or in the lab?

[Gene M.]

Re: 327 Dynoruns

Joe,
What do you mean by "are bracketed by the LT1 and the 30-30"?

Nice power curves..........

[Dick W.]

Re: 327 Dynoruns

It would seem to me that taking a brand new fresh motor and running it to 6000 RPM after it only had 5 minutes of run time would not be a very good idea, but everybody seems to do it and get away with it.

Have seen many race engines cranked, get up to operating temps, and pull 9,000 rpm full power runs

[Michael H.]

Re: 327 Dynoruns

Have seen many race engines cranked, get up to operating temps, and pull 9,000 rpm full power runs

That's how we did it too.

If the cylinders are properly honed, and the ring package is correct, there really isn't any "break in". That's a term from the old days.

[Clem Z.]

Re: 327 Dynoruns

a the corvette factory at BG they fire them up on the line and straight to to rollers where they run them thru the gears to 4500+ RPMs

[Joe C.]

Re: 327 Dynoruns

Joe,
What do you mean by "are bracketed by the LT1 and the 30-30"?

Nice power curves..........

"Are bracketed by" is to say that my cam's 0.050" durations are in-between those of the "30-30" and the LT1.

"30-30": 254/254...................Mine: 248/254................LT1: 242/254

Where the real differences become apparent is when one looks at the J604D durations, AKA "advertised" or "seat to seat" durations.

"30-30": 310/310...................Mine: 294/300..................LT1: 295/310

[Joe C.]

Re: 327 Dynoruns

For clarity, the dynoruns shown in post #1 were done on a Dynojet 224 chassis dyno, and show rear wheel horsepower with SAE correction (77 degrees F., sea level, 29.235 baro, 0% relative humidity). Corrected for losses due to the 6 universal joints, hypoid gears, manual transmission, lack of velocity stack on carburetor, water pump, fan and alternator, "Pull 1" translates to (at least) 450 gross SAE HP.

Engine Analyzer Pro predicted 461 gross SAE HP @ 6300 RPM. Accurate to within 2.2%!

[John H.]

Re: 327 Dynoruns

We did the same thing at Viper - we built our own engines in-house from the bare block up, and the first time they were fired was in the Roll-Test booth. If the bores are properly honed, moly-faced rings seat fully in less than a minute.

[Mike F.]

Re: 327 Dynoruns

What type of exhaust are you using aft of the headers?

Mike