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Sorry, you changed my statement, so now it becomes your statement. What you say may be accurate, but it is your opinion, so give yourself the credit. JMO...
Welcome to the forum 6T2. Sometimes it can be a rough ride, but I think you'll find it to be a responsive bunch of guys with a very deep pool of knowledge.
Welcome to the forum 6T2. Sometimes it can be a rough ride, but I think you'll find it to be a responsive bunch of guys with a very deep pool of knowledge.
I agree, and since I own a C1, it falls in line with the forums for the 40's and 50's cars I own. I have a '55 Nomad, two 56 Bel air hardtops, two '49 Olds. a '42 Mercury, a 54 Packard, and a 1968 Toyota FJ 40. They all have their forums. One of my Olds is somewhat original with the original drivetrain. My other Olds, a '49 Olds 98 convertible has a Chevy LS engine drivetrain, and it is treated like a bastard child by the Olds purist in one of the forums. Classic Olds forum is very similar to this Corvette forum, but they aren't too responsive.
I agree there is a very knowledgeably group of guys here on this forum. The completion of my 327 engine was done with information I garnered from this site, along with that of my previous experience with 265, 327, and 350 SBC's.
I like this site. and I like it that have broken it down by "C" sections.
Bob
sorry, you changed my statement, so now it becomes your statement. What you say may be accurate, but it is your opinion, so give yourself the credit. Jmo...
The rebuild of the 327 engine from my '62 'Vette is finished. I had a goal of one real horsepower (not factory) per cubic inch. They hit that mark on a Dyno with 330hp and 385 lbs torque. With the original 4sp, and a new 3.55 Posi rear end, this should give me all the performance I can handle (Underline "I"). I used the Voodoo hydraulic roller cam, and roller tipped rockers, and the original intake and heads.
I hope to have it on the road in about ten days.
Bob
Was that chassis dyno at the wheel or engine dyno?
Was that chassis dyno at the wheel or engine dyno?
I'm not sure I understand your question. This was not a chassis test as I understand it as the engine is not on the car. The test was done right off the engine which is the most accurate test.
Does this answer your question?
Bob
Ya, I doubt that those gen one 340 or 360 hp engines really had that rated hp. A real 330 hp engine in a C! or C2 should be a blast to drive. Good for you.
This!
The way power is rated today agree......the old "350 hp" didnt feel like much.
I'm not sure I understand your question. This was not a chassis test as I understand it as the engine is not on the car. The test was done right off the engine which is the most accurate test.
Does this answer your question?
Bob
What type of exhaust system was used on the dyno run? Is it the same as you will use when the engine is in the car?
What type of exhaust system was used on the dyno run? Is it the same as you will use when the engine is in the car?
They used their own. I plan to use original 2.5" headers, with 2.5" exhaust pipes out to Dynomax Super Turbo 14" mufflers. Same as on the 327 in my '56 Chevy HT. They sound seet.
Bob
Good question. Peak HP was at 330.9hp @ 5300rpm ( 326.5hp @ 5700rpm ). Max Torque was 384,7 lb-ft @ 3700rpm. Displacement was raised to 331 CI, and CR at about 9.6 to 9.8. Good answer? I'm adding the Dyno Chart as I'm not quite sure I've given you the specs you asked for.
I will be using it with original 4sp gear box, 3.55 Eaton rear end, and 27.5" tires.
Bob
Some may find this ten year old article interesting and informative: Engine dyno comparison
Thanks for posting that magazine test. I had not seen it before. There were some things they did;however, that made these engines appear to be more powerful than they were In the build, they used an MSD distributor which no doubt had an optimal curve, which the factory distributor wouldn't have had. In addition, they used a 750 Holley carb. The original Holley was a 2818 650. And it appears they dyno tuned both engines, tweaking the jetting on the carb and nozzle sizes on the FI, and they used 1 3/4 tube headers instead of the ram's horn exhaust. It was an interesting article, but I wish they had stayed a little closer to 'as produced' setups
Thanks for posting that magazine test. I had not seen it before. There were some things they did;however, that made these engines appear to be more powerful than they were In the build, they used an MSD distributor which no doubt had an optimal curve, which the factory distributor wouldn't have had. In addition, they used a 750 Holley carb. The original Holley was a 2818 650. And it appears they dyno tuned both engines, tweaking the jetting on the carb and nozzle sizes on the FI, and they used 1 3/4 tube headers instead of the ram's horn exhaust. It was an interesting article, but I wish they had stayed a little closer to 'as produced' setups
I noticed that. I didn't use an MSD diz, but you can see from my spec sheet I am using electronic ignition and a Pertronix Flamethrower coil. I am also using the original 600cfm Carter AFB and the jets were tweaked to complement my Voodoo cam so now I don 't know what the CFM is. They ran three tests, and as far as I know, it was dyno tuned.
Good question. Peak HP was at 330.9hp @ 5300rpm ( 326.5hp @ 5700rpm ). Max Torque was 384,7 lb-ft @ 3700rpm. Displacement was raised to 331 CI, and CR at about 9.6 to 9.8. Good answer? I'm adding the Dyno Chart as I'm not quite sure I've given you the specs you asked for.
I will be using it with original 4sp gear box, 3.55 Eaton rear end, and 27.5" tires.
Bob
The photo is a bit too small to read (and blurs when enlarged). A more clear image would help.
I cannot read the low rpm numbers, but actual lower rpm torque usually beats the model simulation numbers.
An honest 330 flywheel hp in a 3000# car, with under 10 lb/hp, is no dog by any measure. Looks great for what you specified you wanted.
The photo is a bit too small to read (and blurs when enlarged). A more clear image would help.
I cannot read the low rpm numbers, but actual lower rpm torque usually beats the model simulation numbers.
An honest 330 flywheel hp in a 3000# car, with under 10 lb/hp, is no dog by any measure. Looks great for what you specified you wanted.
Sorry about the quality of the pic. I downloaded a text from the machinist. I've tried to enlarge the peak Torque and RPM numbers. I hope it helps. I'm not sure I understand how Low RPM numbers work but I'll take your word for it.
Yeah, I was happy when the machinist called me with the Dyno numbers and he told me the numbers came out great. Kinda like an expectant father being told he had a very health baby. :-)
I noticed that. I didn't use an MSD diz, but you can see from my spec sheet I am using electronic ignition and a Pertronix Flamethrower coil. I am also using the original 600cfm Carter AFB and the jets were tweaked to complement my Voodoo cam so now I don 't know what the CFM is. They ran three tests, and as far as I know, it was dyno tuned.
i believe the AFB carburetor is rated at 625 cfm. Changing the jets will not affect the cfm flow. That is contolled by the size of the venturis and the base plate. If you want to pick up some horsepower pretty easily, change the 340 horse intake out for the 68-69 Z28 intake, and put on a 750 Holley. You will gain about 25-30 horsepower. The 63 intake has some square corners in the runners
The AFB is rated at 550 CFM, and the later Holley at 585, both at 1.5" Hg depression, which is the defacto industry standard depression for rating 4-bbl. carbs. Two-barrel flow ratings are at 3".
The LT-1 manifold is good for 5-10 HP and a larger carb no more than a handful.
I question the peak torque rating of over 380 lb-ft. Typical small blocks with a CR close to ten produce about one lb-ft per cubic inch of displacement on a lab dyno. Peak torque is primarily a function of displacement and CR. Within the 327 family peak torque ratings ranged from 344 to 360 lb-ft, a range of less than five percent, but the highest power rating, 375 is 50 percent more than the lowest, 250. Of course, both torque and power ratings were overstated by at least ten percent, but relative comparisons washout the nonsense.
Headers and a high overlap cam will improve peak torque and power, but in the car with manifolds and mufflers most of whatever they contributed on the lab dyno will disappear.
That's why I recommend chassis dyno tests. It's the as-installed in the chassis available rear wheel HP that counts, not what a lab dyno shows, and as is typical the test started in the mid 3000 range, so you don't know what it does below that range, which is where you spend most of your driving time around town.
The "327 LT-1" configuration I referenced earlier makes, with OE exhaust manifolds and STP correction on a lab dyno, low 330s lb-ft peak torque at 4500 with 80 percent available at 2000 and about 360 HP at 6500. On a chassis dyno with SAE correction peak torque is in the 270-280 range and about 280 RWHP.
01-17-2019, 04:45 PM
