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New article today over at Hotrod: How to Build a Lightweight 650-hp Big-Block Mopar for the Street


It is interesting to compare the 500 inch Mopar article with the 440 inch LS article that is on the same page: https://www.hotrod.com/articles/440-inch-big-block-ls-dart-dyno/

The LS engine is more impressive to me than the Mopar build. The Mopar build is very expensive with modest results. The LS build has a lot more bang for the buck. The Valiant could've used a stroked Magnum engine to go just as fast with way less money spent and an easier install. The Valiant wasn't set up to handle that much power so there was no reason to build a $30K engine for it.
 
You can tell all of that without even knowing all of the specs? Or am I missing something here because I couldn't find them. It looks like a high horsepower street car to me that is not optimal for the track.

If you know all of the specs please let us know so we can come up with our own conclusions

If you have a Moroso slide rule you can figure this stuff out. 121 mph equals a weight to power ratio of 7.40 which means either the car weighs 4800 lbs with 650 hp or that it doesn't have 650 hp. That engine should easily make 650 hp and the car most likely weighs around 3200 lbs so the mph should be 135. My guess is that the car can't hook up and that the driver didn't keep his foot in it all the way down the track. That car is probably scary to drive with that much power. If you look at the pictures of the car you can see that it isn't a race car.
 
I have an engine very similar to this being built right now. Same Indy block and same Indy EZ heads. The engine I'm having built will be a little bigger with more compression and a bigger cam. It should make around 900 hp with the EZ heads. Once the car is prepped for more power we'll switch to 572-13 heads and then the engine should make around 1000 hp.
 
You can tell all of that without even knowing all of the specs? Or am I missing something here because I couldn't find them. It looks like a high horsepower street car to me that is not optimal for the track.

If you know all of the specs please let us know so we can come up with our own conclusions

Absolutely! It's called math and experience. If you can't handle those, the Moroso slide rule (like Andy mentioned) or Wallace Calculator website is your friend.
 
Absolutely! It's called math and experience. If you can't handle those, the Moroso slide rule (like Andy mentioned) or Wallace Calculator website is your friend.

Lol OK. smart ***! Lets say I am as dumb as a stump. Please explain to me how you got all the information to determine, what rear gear, what transmission, auto or stick, what converter, what are the ratio's in the manual transmission, what tire size, what kind of tires (drag radials, slicks or street) need I go on?
The way I see it is that you're crystal ball works much better than mine at picking the parts in this car.
 
Lol OK. smart ***! Lets say I am as dumb as a stump. Please explain to me how you got all the information to determine, what rear gear, what transmission, auto or stick, what converter, what are the ratio's in the manual transmission, what tire size, what kind of tires (drag radials, slicks or street) need I go on?
The way I see it is that you're crystal ball works much better than mine at picking the parts in this car.

If you have the HP and weight (easy to assume weight with an a body as there are tons of similar examples) the gearing isn't going to be all that critical with the stump pulling torque of a BB stroker. 3.23-4.10 gears are going to yield very similar results. Auto or stick isn't going to matter much either. We're talking about the mph in the quarter which is the indicator of hp. Less than ideal tires or shitty suspension will effect e.t. but (I care little about the e.t.) but, in this case, it's not terribly off. They gave gross HP and assuming a weight of 3,400 lbs., this car is a BIG underperformer! As in one plug wire off!

We make 600 hp with very conservative 505 with 11" converter and 3.54 gears. At 3,700 lbs it runs almost identical #'s to what this car does. 11.19 @ 121 mph.

Just because you don't understand what I'm saying doesn't mean it isn't true.

Like Andy said, the car either weighs 4,800 lbs. or doesn't make anywhere near 650 hp. Logic tells you it cannot be that heavy so why is it such an underperformer?! Honestly, 650 hp out of that combo of parts isn't that great either but it isn't making anywhere near that!

I'd take offense to the "smart ***" remark but I see you are from New Jersey so that explains a lot including why we are even having this conversation.
 
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If you have the HP and weight (easy to assume weight with an a body as there are tons of similar examples) the gearing isn't going to be all that critical with the stump pulling torque of a BB stroker. 3.23-4.10 gears are going to yield very similar results. Auto or stick isn't going to matter much either. We're talking about the mph in the quarter which is the indicator of hp. Less than ideal tires or shitty suspension will effect e.t. but (I care little about the e.t.) but, in this case, it's not terribly off. They gave gross HP and assuming a weight of 3,400 lbs., this car is a BIG underperformer! As in one plug wire off!

We make 600 hp with very conservative 505 with 11" converter and 3.54 gears. At 3,700 lbs it runs almost identical #'s to what this car does. 11.19 @ 121 mph.

Just because you don't understand what I'm saying doesn't mean it isn't true.

Like Andy said, the car either weighs 4,800 lbs. or doesn't make anywhere near 650 hp. Logic tells you it cannot be that heavy so why is it such an underperformer?! Honestly, 650 hp out of that combo of parts isn't that great either but it isn't making anywhere near that!

I'd take offense to the "smart ***" remark but I see you are from New Jersey so that explains a lot including why we are even having this conversation.

Lol, Your Podunk attitude doesn't help. Mock me all you want. I am fine with that. I see now that you know everything and I am wasting my time here. Have a good day cow tipping, Elmer.
 
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I was just reading the OP article. Isn't that cam really small for a performance BB stroker application. 245/251 at .050
 
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I read the drag test, time slips are from 2015.
One thing though, the dyno rate was 600 rpm/sec.. isn't it usually 300?
Could someone explain what this means? Is this a rate of engine acceleration on the dyno? Higher number being faster revving?
 
If you have a Moroso slide rule you can figure this stuff out. 121 mph equals a weight to power ratio of 7.40 which means either the car weighs 4800 lbs with 650 hp or that it doesn't have 650 hp. That engine should easily make 650 hp and the car most likely weighs around 3200 lbs so the mph should be 135. My guess is that the car can't hook up and that the driver didn't keep his foot in it all the way down the track. That car is probably scary to drive with that much power. If you look at the pictures of the car you can see that it isn't a race car.

I agree as I always look at how a car mph's. And thats because so many with street cars that run them say ......oh its an 11.0 car when I get it to hook. Then I look at the timeslip of 12.45 @ 109 mph and I say oh so you lifted way before the finish line ? And you get that funny look and then when I say at 109 mph you are lucky to see low 12's they really get a funny look. That 121 mph is what caught my eye first as if he kept his foot in it that tells how much power its making and he will be lucky to hit 10.90's at 121 mph if thats the true mph. I agree that if it only pulled an honest 121mph something is off as thats lucky to be 600 flywheel hp in a 3700 lb car. Ron
 
I agree as I always look at how a car mph's. And thats because so many with street cars that run them say ......oh its an 11.0 car when I get it to hook. Then I look at the timeslip of 12.45 @ 109 mph and I say oh so you lifted way before the finish line ? And you get that funny look and then when I say at 109 mph you are lucky to see low 12's they really get a funny look. That 121 mph is what caught my eye first as if he kept his foot in it that tells how much power its making and he will be lucky to hit 10.90's at 121 mph if thats the true mph. I agree that if it only pulled an honest 121mph something is off as thats lucky to be 600 flywheel hp in a 3700 lb car. Ron
Yep, someone who races and has experience that gets it! Mph and weight is all you need to know.
 
Yep, someone who races and has experience that gets it! Mph and weight is all you need to know.
At least half of all you need to know. Throw in some aerodynamics and track location/conditions. Some tracks are -900ft sea level ... then take same car to Colorado..
 
Could someone explain what this means? Is this a rate of engine acceleration on the dyno? Higher number being faster revving?
Yes its similar to testing your engine in an Imperial vs a dragster.
 
I ran my street car for years on BFG Radial T/A's. 13.60@107. Borrowed a pair of slicks. 12.30@109. Opened the exhaust (it had 2 1/2 no tail pipes) 11.88@111. Better converter and a 4.30 in place of the 3.91, 11.65@117. So it lost 2 seconds and gained 10 mph with the exact same engine combo. To add; the cam was swapped. No Et improvement but gained 5 mph, 11.70@122. Now the converter was way too tight. Swapped the converter again, 11.05@123
Doug
 
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I ran my street car for years on BFG Radial T/A's. 13.60@107. Borrowed a pair of slicks. 12.30@109. Opened the exhaust (it had 2 1/2 no tail pipes) 11.88@111. Better converter and a 4.30 in place of the 3.91, 11.65@117. So it lost 2 seconds and gained 10 mph with the exact same engine combo. To add swapped the cam 11.70@122. Swaped converter again 11.05@123
Doug

So I guess it was all due to an under performing engine. Right? :lol:
 
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