Bad B-rad
Well-Known Member
In the most recent issue of Mopar Action, they have an article on the different types of engine dyno's. (engine/chassis/inertia)
And how some numbers advertised by Chrysler, were accurate, some were BS.
I will quote Richard Ehernberg from the article:
"The 1966 318 poly 2bbl was rated at 230hp @4,400rpm(which was close to valve float)
The 1965 273 4bbl has much higher compression, better heads, much more camshaft, a 480cfm AFB carb (topped with an unsilenced air cleaner) 2.50 inch straight through exhaust(not reverse flow) single plane manifold, and was perfectly happy at 6,000+rpm all day long. It was rated at 235hp @5,200rpm.
All things being equal(same car, same gears,etc) the 273 car would be in the next zip code while the poly 2bbl was wheezing along. 5 hp different, my ***"- Ehernberg
I know that was the authors opinion, but I am sure we have all heard, the 340, was WAY under rated, as was the 426 Hemi.
I have always wanted to find real engine dyno numbers for as delivered, engines, but I have only ever found ones on the 426 Hemi.
Another rating that I have ALWAYS been curious about was the 383 4bbl 330HP, and the 383 MAGNUM/Roadrunner engines at 335HP.
I know cam is different, and that power will come on at different rpm between the two, but 5 peak HP, IMO you could not even feel 5 hp, when installed in a car.
I have no experience, with driving or owning a 440 6BBl, but I was always interstead in the real numbers on that engine also, as I have read this was also underrated a bit. With the claimed reason being the real HP numbers came to close to the Hemi's rating
I will quote the article again:
"Countless other examples, one that comes to mind is the mid 60's 383 4bbl rated at 330 ponies @4,600rpm VS the 1968 Roadrunner 383's 335HP (@5200rpm) the 68 906 heads, vastly improved manifolding, AVS carb, and mainly a camshaft that was virtually full on race, next to mid 60's stuff. Yeah 5 hp."--Richard Ehrenberg
He goes on to offer some proof of the factory fudging with the HP numbers, by showing a chart from 1971 when Chrysler published both gross and net HP ratings,( engines were unchanged) and comparing the 318 vs the 340's numbers.
The 318 lost 33% of its HP rating from gross to net, but the 340(claimed to be underrated), only lost 9%
This looks to lend creditability toward the fact that the 340 WAS underrated.
I have seen videos from Nicks Garage, and he dyno's a stock 426 Hemi, I have seen a few stock 426 Hemi dyno videos, but never a 383 4bbl, vs 383 Roadrunner.
Even a video or 1/4 miles time slips of a 383 Roadrunner, vs a 383 Satellite(or similar weight car)
Has any major car mag ever done a test to see how accurately the ratings hold up?
Or any published chart of real HP number vs claimed HP?
I would be interstead in all of Mopars engines, from slant 6, to 6 pack.
Thanks.
And how some numbers advertised by Chrysler, were accurate, some were BS.
I will quote Richard Ehernberg from the article:
"The 1966 318 poly 2bbl was rated at 230hp @4,400rpm(which was close to valve float)
The 1965 273 4bbl has much higher compression, better heads, much more camshaft, a 480cfm AFB carb (topped with an unsilenced air cleaner) 2.50 inch straight through exhaust(not reverse flow) single plane manifold, and was perfectly happy at 6,000+rpm all day long. It was rated at 235hp @5,200rpm.
All things being equal(same car, same gears,etc) the 273 car would be in the next zip code while the poly 2bbl was wheezing along. 5 hp different, my ***"- Ehernberg
I know that was the authors opinion, but I am sure we have all heard, the 340, was WAY under rated, as was the 426 Hemi.
I have always wanted to find real engine dyno numbers for as delivered, engines, but I have only ever found ones on the 426 Hemi.
Another rating that I have ALWAYS been curious about was the 383 4bbl 330HP, and the 383 MAGNUM/Roadrunner engines at 335HP.
I know cam is different, and that power will come on at different rpm between the two, but 5 peak HP, IMO you could not even feel 5 hp, when installed in a car.
I have no experience, with driving or owning a 440 6BBl, but I was always interstead in the real numbers on that engine also, as I have read this was also underrated a bit. With the claimed reason being the real HP numbers came to close to the Hemi's rating
I will quote the article again:
"Countless other examples, one that comes to mind is the mid 60's 383 4bbl rated at 330 ponies @4,600rpm VS the 1968 Roadrunner 383's 335HP (@5200rpm) the 68 906 heads, vastly improved manifolding, AVS carb, and mainly a camshaft that was virtually full on race, next to mid 60's stuff. Yeah 5 hp."--Richard Ehrenberg
He goes on to offer some proof of the factory fudging with the HP numbers, by showing a chart from 1971 when Chrysler published both gross and net HP ratings,( engines were unchanged) and comparing the 318 vs the 340's numbers.
The 318 lost 33% of its HP rating from gross to net, but the 340(claimed to be underrated), only lost 9%
This looks to lend creditability toward the fact that the 340 WAS underrated.
I have seen videos from Nicks Garage, and he dyno's a stock 426 Hemi, I have seen a few stock 426 Hemi dyno videos, but never a 383 4bbl, vs 383 Roadrunner.
Even a video or 1/4 miles time slips of a 383 Roadrunner, vs a 383 Satellite(or similar weight car)
Has any major car mag ever done a test to see how accurately the ratings hold up?
Or any published chart of real HP number vs claimed HP?
I would be interstead in all of Mopars engines, from slant 6, to 6 pack.
Thanks.