1978 NYB New Engine.....

1978 NYB said:
So....I'm going from 210 HP to 400 HP. And it is still a daily driver and has vacuum for the brakes.
Click to expand...

When this thread came out, I also went and looked up the company. I've been planning on rebuilding the engine in my Imperial and giving it a bit of an "upgrade" as well, so this is right in line with my plans, right down to the consideration of aluminum heads. At $6500 for a complete engine, that's a compelling option. I wonder what shipping to me would cost. They'll be getting a call.

The reason for the quote is that these are not really comparable numbers. 210 is SAE Net and 400 is.... not. There was the change from SAE Gross to SAE Net in the 70s, and that would account for a significant amount the difference between the two power ratings. But also in there is that the SAE standard was pretty specific about how it was run and calculated, but the rating from this shop is... I don't know. Is it on the SAE standard, or is it just what their dyno reads? I'm not saying they're being dishonest, but they're not going to be doubling the power. It would be awesome if they could put a factory reman on their dyno to compare.
 
Very rough rule of thumb. And I mean VERY rough.
Rear wheel horsepower can be up to 1/2 the hp at the flywheel on a test stand in a climate controlled lab.
Up to aprox 1970, manufacturers rated their engines at the flywheel. Then the feds made them advertise hp at the wheels using a formula based on test stand hp. Thus the huge drop in the early 70s.

The last time I dyno'd an engine, years ago, my Corvette was rated aprox 400 hp at the wheels. That meant it put out way more power than the 1967 L-88 advertised rating. Not to say the L-88 wasn't grossly UNDERrated, tho....
 
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bajajoaquin said:
When this thread came out, I also went and looked up the company. I've been planning on rebuilding the engine in my Imperial and giving it a bit of an "upgrade" as well, so this is right in line with my plans, right down to the consideration of aluminum heads. At $6500 for a complete engine, that's a compelling option. I wonder what shipping to me would cost. They'll be getting a call.

The reason for the quote is that these are not really comparable numbers. 210 is SAE Net and 400 is.... not. There was the change from SAE Gross to SAE Net in the 70s, and that would account for a significant amount the difference between the two power ratings. But also in there is that the SAE standard was pretty specific about how it was run and calculated, but the rating from this shop is... I don't know. Is it on the SAE standard, or is it just what their dyno reads? I'm not saying they're being dishonest, but they're not going to be doubling the power. It would be awesome if they could put a factory reman on their dyno to compare.
Click to expand...
commando1 said:
Very rough rule of thumb. And I mean VERY rough.
Rear wheel horsepower can be up to 1/2 the hp at the flywheel on a test stand in a climate controlled lab.
Up to aprox 1970, manufacturers rated their engines at the flywheel. Then the feds made them advertise hp at the wheels using a formula based on test stand hp. Thus the huge drop in the early 70s.

The last time I dyno'd an engine, years ago, my Corvette was rated aprox 400 hp at the wheels. That meant it put out way more power than the 1967 L-88 advertised rating. Not to say the L-88 wasn't grossly UNDERrated, tho....
Click to expand...

Well, to start with, they are using 9.5 to 1 piston, a cam which is a lot better than a stock 1969 big block cam, and big valve aluminum heads. The smog motors barely had 8 to 1 pistons and a **** cam and barely made 200 hp. The 69-71 big blocks made 375 hp so I would say it is safe to expect 430 hp from the Carolina Machine Engine people.
 
commando1 said:
Very rough rule of thumb. And I mean VERY rough.
Rear wheel horsepower can be up to 1/2 the hp at the flywheel on a test stand in a climate controlled lab.
Up to aprox 1970, manufacturers rated their engines at the flywheel. Then the feds made them advertise hp at the wheels using a formula based on test stand hp. Thus the huge drop in the early 70s.

The last time I dyno'd an engine, years ago, my Corvette was rated aprox 400 hp at the wheels. That meant it put out way more power than the 1967 L-88 advertised rating. Not to say the L-88 wasn't grossly UNDERrated, tho....
Click to expand...

We're saying roughly the same thing, I think, but there are some corrections.

Companies aren't required to give wheel horsepower ratings. It's still at the flywheel. The difference is SAE Gross versus SAE Net. Gross is the idealized number of the engine with every possible advantage: no accessories, air cleaners, free-flowing exhaust, etc. Net is the rating as packaged in the car. Air cleaners, alternators, manifolds and the rest. Both are still at the flywheel. There may be other changes in the measurement with temp, pressure or other stuff, I am not sure.

The switch-over from Gross to Net happened during the early smog years, so there was also a year-to-year drop happening because engines were genuinely less powerful, and the Net rating was lower than the Gross rating even before power drop offs. Because of this, you can't look at the previous year's engines and get a percentage from that. Add in the advertising element where the published numbers were also unreliable, and it's hard to tell. I've heard 15% to 20%. 25% is probably not unreasonable.

There's also a step down from flywheel to wheel horsepower. Transmission, rear-end, tires, and all the joints add up to parasitic loss. Again, 15% to 20% are the things I've read and been told, and 25% is probably not too far out there. This doesn't even begin to take into account the issue that every dyno is different. (I don't know if I've read it or had a friend tell me that there are dynos in town which are known to give off high numbers and they're favored by the tuner crowd so they can wave around high numbers for bragging rights.)

Both of those add up to what I think you're saying (up to 50%), but I think it should read that there's up to a 50% drop from Gross rated to actual rear-wheel horsepower.

So what does this all mean? I don't know. 400s were all rated Net, so there's no Gross version to compare to. But what would a 210 have been rated at gross? Allpar says the drop from Gross to Net was up to 50 hp in "rating." A 25% difference would be 268 hp. So maybe 275 rated Gross in adspeak?

Moving from 275 to 430 Gross HP from a lumpy cam, higher compression, aluminum heads, better manifold? that's a 35-ish percent increase in power. I buy that. If some of that is also the difference between dynos or more optimized "standard" test conditions, it's even more within the realm of reasonability.

And it's going to be a sweet engine.
 
1978 NYB said:
Well, to start with, they are using 9.5 to 1 piston, a cam which is a lot better than a stock 1969 big block cam, and big valve aluminum heads. The smog motors barely had 8 to 1 pistons and a **** cam and barely made 200 hp. The 69-71 big blocks made 375 hp so I would say it is safe to expect 430 hp from the Carolina Machine Engine people.
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Yep. You wrote this while I was writing mine. I agree completely. Didn't mean to imply that these guys weren't doing what they say they're doing. Just that you're not looking at a doubling of power. (Not that you were planting a stake in the ground over it.)
 
I'm pretty much getting a well built engine with better characteristics than the smog motor.....and it has a 12 month, 12,000 mile warranty. The cost of building it myself or have someone else build it isn't that different with the expensive machine shop prices today. These guys build thousands of Mopar big blocks and have a solid reputation.
 
Your NYB upgrade is inspiring Bob. Can’t wait to see the end result with all the Goodies in detail... You’ve got me thinking. Dammit!
 
My take is gross is a "fake" number based on a tweaked dyno engineering mule engine, not what was sitting on the lot in 1969, same configuration not tweaked. Net is a more realistic number to the tune/accessories/air cleaner. The number they are quoting is a dyno, no accessories figure. Timing is correct, jetting is correct, HEADERS, no mufflers. Still with crappy manifolds accessories attached in the car 15-20% driveline loss Bob will still be at 300 or so at the wheels, very noticeable compared to the 150-175 from his worn smog 400 in the car. Do it Bob. Does the distributor you using have vacuum advance? If not I would change that to one that does, MSD makes them. You need it for all the street/highway miles you will do. Carry on
 
70bigblockdodge said:
My take is gross is a "fake" number based on a tweaked dyno engineering mule engine, not what was sitting on the lot in 1969, same configuration not tweaked. Net is a more realistic number to the tune/accessories/air cleaner. The number they are quoting is a dyno, no accessories figure. Timing is correct, jetting is correct, HEADERS, no mufflers. Still with crappy manifolds accessories attached in the car 15-20% driveline loss Bob will still be at 300 or so at the wheels, very noticeable compared to the 150-175 from his worn smog 400 in the car. Do it Bob. Does the distributor you using have vacuum advance? If not I would change that to one that does, MSD makes them. You need it for all the street/highway miles you will do. Carry on
Click to expand...

MSD 8386 with vacuum advance is the distributor I'm using and will be on the engine when dyno'ed . Also will have MSD wires and the Holley SS-780-VS carb on it as well.
 
I'm very happy for you.. this is exciting! Looking forward to your progress>>>completion on this one.
 
70bigblockdodge said:
My take is gross is a "fake" number based on a tweaked dyno engineering mule engine, not what was sitting on the lot in 1969, same configuration not tweaked. Net is a more realistic number to the tune/accessories/air cleaner. The number they are quoting is a dyno, no accessories figure. Timing is correct, jetting is correct, HEADERS, no mufflers. Still with crappy manifolds accessories attached in the car 15-20% driveline loss Bob will still be at 300 or so at the wheels, very noticeable compared to the 150-175 from his worn smog 400 in the car. Do it Bob. Does the distributor you using have vacuum advance? If not I would change that to one that does, MSD makes them. You need it for all the street/highway miles you will do. Carry on
Click to expand...

The Gross to Net rating changed in 1971, at least for Pontiac engines. I have the 1971 AMA engine specs which show the differences in the engine HP & Torque ratings. This will give you an example of the changes. As you stated, Gross figures were on the engine stand with no accessories, exhaust, or even the water pump hooked up via belts. The Net figures included all accessories and exhaust system.

The 1971 AMA specs for the 400CI & 455CI include both the Gross and Net HP & TQ numbers for that year. This was the year that compressions dropped, HP & TQ ratings went from Gross to Net, and rated power levels went down.

The 400CI, 8.2 compression, 4Bbl, dual exhaust had a Gross HP of 300 @ 4800RPM and a Net HP of 255 @ 4400 RPM (200HP @ 4000 RPM with single exhaust). Gross TQ was 400 @ 3600 RPM and Net was 340 @ 3200 RPM (305TQ @ 2800 RPM with single exhaust)

The 455CI HO, 8.4 Compression, 4 Bbl, dual exhaust has a Gross HP of 335 @ 4800 RPM and a Net HP of 310 @ 4400 RPM. Gross TQ was 480 @ 3600 RPM and Net was 410 @ 3200 RPM.

The standard 455CI, 8.2 compression, 4Bbl, dual exhaust had a Gross HP of 325 @ 4400 RPM and a Net HP of 260 @ 4000 RPM (230HP @ 4400 RPM with single exhaust). Gross TQ was 455 @ 3200 RPM and Net TQ was 380 @ 2800 RPM (360TQ @ 2800 RPM with single exhaust).
 
PontiacJim said:
The Gross to Net rating changed in 1971, at least for Pontiac engines. I have the 1971 AMA engine specs which show the differences in the engine HP & Torque ratings. This will give you an example of the changes. As you stated, Gross figures were on the engine stand with no accessories, exhaust, or even the water pump hooked up via belts. The Net figures included all accessories and exhaust system.

The 1971 AMA specs for the 400CI & 455CI include both the Gross and Net HP & TQ numbers for that year. This was the year that compressions dropped, HP & TQ ratings went from Gross to Net, and rated power levels went down.

The 400CI, 8.2 compression, 4Bbl, dual exhaust had a Gross HP of 300 @ 4800RPM and a Net HP of 255 @ 4400 RPM (200HP @ 4000 RPM with single exhaust). Gross TQ was 400 @ 3600 RPM and Net was 340 @ 3200 RPM (305TQ @ 2800 RPM with single exhaust)

The 455CI HO, 8.4 Compression, 4 Bbl, dual exhaust has a Gross HP of 335 @ 4800 RPM and a Net HP of 310 @ 4400 RPM. Gross TQ was 480 @ 3600 RPM and Net was 410 @ 3200 RPM.

The standard 455CI, 8.2 compression, 4Bbl, dual exhaust had a Gross HP of 325 @ 4400 RPM and a Net HP of 260 @ 4000 RPM (230HP @ 4400 RPM with single exhaust). Gross TQ was 455 @ 3200 RPM and Net TQ was 380 @ 2800 RPM (360TQ @ 2800 RPM with single exhaust).
Click to expand...
So what is the explanation for the peak changing rpm by like 10%.
 
There could be two reasons. 1) when you add air cleaners, mufflers, manifolds, etc, the torque peak naturally goes down. 2) they knew that unleaded gas was coming so dropped performance a bit as well.

Or perhaps 3) a bit of both.

Edited to add that I didn’t see that the other post was gross and net for the same year. So I’m guessing it’s pretty much number one.
 
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bajajoaquin said:
The reason for the quote is that these are not really comparable numbers. 210 is SAE Net and 400 is.... not. There was the change from SAE Gross to SAE Net in the 70s, and that would account for a significant amount the difference between the two power ratings. But also in there is that the SAE standard was pretty specific about how it was run and calculated, but the rating from this shop is... I don't know. Is it on the SAE standard, or is it just what their dyno reads? I'm not saying they're being dishonest, but they're not going to be doubling the power. It would be awesome if they could put a factory reman on their dyno to compare.
Click to expand...

That was part of my reasoning in post #68. Engine dynos are not the be all end all - they are a tuning tool. Plus factory ratings are not exactly a standard dyno pull and result. Be it in Net or Gross configuration - the factory had multiple dynos and teams of engineers working 24 hrs a day on them. They would test an engine at a given rpm, tune for maximum power at that rpm, then move on to the next rpm point. They would maximize the readings at each point, then plot the points into a singular power curve. So the final reading(s) were a compilation of maximized values. If it was low, they'd fudge it higher or round up, unless there was a reason to be lower (insurance, sanctioning body rules, etc). Plus production tolerances on all parts stack, and the law of averages says some engines will beat the rating, some will equal it, and some will not equal it. That's the reality. Comparing the values from a Net test vs a Gross is an apples-to-goat test.
If indeed every engine is dyno tested, the engine will be tested for a gross output number and will include parts that make it easy to plug onto the dyno: dyno headers, dyno fed fuel, a dyno carb, dyno provided water, no air filter, etc. That's all why I said the numbers in the chassis will be lower. It's not the builder's fault - just the difference between a dyno and a car's engine bay.
I also have little doubt the OP will like the engine he gets. Just don't get wrapped up in numbers.
 
It's official.... I won't be getting my engine for the NYB for another 2 weeks. They still have to port and polish the heads and assemble the engine and run it on the dyno. I was hoping to get the engine installed and running by Carlisle.
 
There are a few dyno YouTube videos from Nick's Garage. On a 440/375 stock rebuild with the kitted orig carb, "the numbers" were very accurate with the factory rating in '67. A few more horses with a larger Holley 4bbl.

CBODY67
 
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