Question for the experts: 1970 440 vs 1971 440

[Bossssssss]

Hi Gents,
Can you tell me what made the difference in HP ratings between the 1970 vs 1971 440 that were available in the Sport Fury? My understanding is the 1970 was rated at 350HP and the 1971 440 was rated at 375HP. I am not sure of the torque ratings of each (maybe somebody can chime in on that as well).
What specifically was the difference(s) that allowed the 1971 to make more HP? Was it the cam? or compression ratio or perhaps several things?

Thank you in advance.
Mark

 

[69CoronetRT]

The library at Hamtramck Historical has that and more.

The 1970 Hamtramck Registry Library Page (1970 - 1974)

 

[CBODY67]

The '71 B/RB engines had a little less compression ratio, but not much other than that and emissions-related tuning calibrations. DO look for camshsaft/carburetor/distributor curve differences, at H-H and in the FSMs at www.MyMopar.com.

The old "CARS" magazine did dyno tune tests on a '70 383/335 and its '71 counterpart. Altered distributor advance curves, carb jetting, and such. When done, both cars chassis dyno'd within about 5 horsepower of each other. So much for "smog-strangled" '71 engines.

ALSO, if there are any "AMA Specifications" listed for Plymouth C-bodies in those model years, do check them out. Even download the files for future use!

Just some thoughts,
CBODY67

 

[FURYGT]

Hi Gents,
Can you tell me what made the difference in HP ratings between the 1970 vs 1971 440 that were available in the Sport Fury? My understanding is the 1970 was rated at 350HP and the 1971 440 was rated at 375HP. I am not sure of the torque ratings of each (maybe somebody can chime in on that as well).
What specifically was the difference(s) that allowed the 1971 to make more HP? Was it the cam? or compression ratio or perhaps several things?

Thank you in advance.
Mark

In 1970 in Furys you got the non-HP 350 HP 440 unless you ordered the GT with the 6 barrel option, which got you 390 HP. In 1970 the Dodge and Chrysler C Body's offered the 375 HP 440 as an option (standard on the Hurst). In 1971 the HP 440 was standard in the Sport Fury GT but dropped 5 HP to 370 due to a small compression drop. The 375 HP 440 was also available in other Fury models in 1971 except for station wagons, which only could be optioned with the 350 non-HP 440. I hope this helps.

 

[Bossssssss]

Thanks Gents - but I am still not clear on the specific difference(s) between the 70 350HP rated motor vs 71 375HP rated motor. I see there was a compression drop in '71 based on BODY67's response. One would think the 70 with high compression would make more HP. So this seems counterintuitive to me. Were the heads the same between the two years? If so, then I assume the piston was changed to drop the compression in '71? Were the cams the same? Not trying to nitpic, just trying to understand the mechanical differences between the engine's HP rating. How about the carb? were they the same between the two? Maybe better free flowing exhaust manifolds? Things like that are what I was trying to pin down. Thanks again for all your help.
Mark

 

[FURYGT]

Thanks Gents - but I am still not clear on the specific difference(s) between the 70 350HP rated motor vs 71 375HP rated motor. I see there was a compression drop in '71 based on BODY67's response. One would think the 70 with high compression would make more HP. So this seems counterintuitive to me. Were the heads the same between the two years? If so, then I assume the piston was changed to drop the compression in '71? Were the cams the same? Not trying to nitpic, just trying to understand the mechanical differences between the engine's HP rating. How about the carb? were they the same between the two? Maybe better free flowing exhaust manifolds? Things like that are what I was trying to pin down. Thanks again for all your help.
Mark

350 HP vs 375/370 HP 440's. Same heads although there was a slight change to the '71 heads. The difference is the cam, the use of HP exhaust manifolds vs log style exhaust manifolds (which did not flow as well), different carb and some other minor changes.

 

[70bigblockdodge]

Probably lost more from ignition timing than anything else, timing backed up to help emissions. Not that 70 specs were much better. They all need retimed to what the engine needs not what the sticker on the fenderwell says.
Full disclosure, this does not work on a slant six.

 

[rapidtrans]

Wasn’t 71 model year the change to regular fuel capability for all but Hemi and 6 Pack engines?
FWIW. We had a couple 383 4bbl cars that developed issues on regular fuel.

 

[Davea Lux]

The 375hp engine ran a hotter cam with heavier valve springs. 375 hp retained the AVS carb, 350hp ran the Holly carb (C-Bodies). 375 hp also had the high performance manifolds as noted, 350 ran log manifolds. The 375hp engine was also externally balanced with the heavier forged steel crank. The harmonic balancer and torque convertor are also weighted to accommodate the external balance. 350 hp engines are internally balanced. The U-Code 375hp engine was widely produced as part of the police option package for both 70-71 in the Fury.

Dave

 

[CBODY67]

GM was the first to use unleaded regular fuel across the board from April. 1971 production onward. All V-8s were right at 8.5CR, other than the optional Corvette motor, at 9.0CR.

Chrysler dropped the V-8 compression ratio in 1972, to 8.2CR or thereabouts. The 383HP and 440HP were still at about 9.7CR for 1971. Full unleaded capabilities arrived with the 1973 model year.

Not sure why Civilian Plymouths only got the 440/350 in '70, unless it was to make the 440 6bbl option more viable and special?

CBODY67

 

[Davea Lux]

GM was the first to use unleaded regular fuel across the board from April. 1971 production onward. All V-8s were right at 8.5CR, other than the optional Corvette motor, at 9.0CR.

Chrysler dropped the V-8 compression ratio in 1972, to 8.2CR or thereabouts. The 383HP and 440HP were still at about 9.7CR for 1971. Full unleaded capabilities arrived with the 1973 model year.

Not sure why Civilian Plymouths only got the 440/350 in '70, unless it was to make the 440 6bbl option more viable and special?

CBODY67

440 6BBL was only available on the SFGT, not offered on other C-Bodies. (It was possible to also get this option on police cruiser, very rare)

Dave

 

[ceebuddy]

Thanks Gents - but I am still not clear on the specific difference(s) between the 70 350HP rated motor vs 71 375HP rated motor. I see there was a compression drop in '71 based on BODY67's response. One would think the 70 with high compression would make more HP. So this seems counterintuitive to me. Were the heads the same between the two years? If so, then I assume the piston was changed to drop the compression in '71? Were the cams the same? Not trying to nitpic, just trying to understand the mechanical differences between the engine's HP rating. How about the carb? were they the same between the two? Maybe better free flowing exhaust manifolds? Things like that are what I was trying to pin down. Thanks again for all your help.
Mark

As was the case in other years, in 1970 and 1971 both a base 440 engine and a high-performance version of the 440 was offered. The high-performance version went by the name of "Super Commando" with Plymouth, "Magnum" with Dodge and "TNT" with Chrysler.

Stricter tailpipe emissions regulations called for a lowered compression in some engines, among other things, for 1971, resulting in a slight drop of power over the previous year.

Beginning in 1971, manufacturers also had to state the then new net horsepower (net hp) figures versus the previous brake horsepower (bhp) which were due to a different test setup and resulted in significantly lower numbers.

The horsepower ratings were:
1970 standard 440: 350 bhp
1971 standard 440: 335 bhp (220 net hp)
1970 high-performance 440: 375 bhp
1971 high-perofrmance 440: 370 bhp (305 net hp)

In both years, the high-performance version of the 440 eninge sported low restriction exhaust manifolds, larger diameter valves and a special camshaft (among other items) to set it apart from teh base 440 engine. The 1970 high-performance 440 featured the same 9.7 to 1 compression ratio as the base 440 engine. The 1971 high-performance 440 engine had a 9.5 to 1 compression ratio while the 1971 base 440 engine's compression ratio had been lowered to 8.8 to 1.

The 1970 440 six pack engine had an even higher compression ratio of 10.5 to 1. The six pack was not offered in a C-body in 1971 anymore.

 

[Fury Pursuit]

Dave[/QUOTE]

440 6BBL was only available on the SFGT, not offered on other C-Bodies. (It was possible to also get this option on police cruiser, very rare)

Dave

It was NOT possible to order a fleet 440 6BBL Plymouth or a 440 Six-Pack Dodge, in 1969, 1970 or 1971.

If it was, please provide documentation.

 

[LeBaron1973]

Dave

It was NOT possible to order a fleet 440 6BBL Plymouth or a 440 Six-Pack Dodge, in 1969, 1970 or 1971.

If it was, please provide documentation.[/QUOTE]

If any were built its probably because someone knew who to ask to get the "non-available" equipment as with GM's COPO ordering options. Company executives could also probably get "something special."

 

[69CoronetRT]

It was NOT possible to order a fleet 440 6BBL Plymouth or a 440 Six-Pack Dodge, in 1969, 1970 or 1971.

If it was, please provide documentation.

If any were built its probably because someone knew who to ask to get the "non-available" equipment as with GM's COPO ordering options. Company executives could also probably get "something special."[/QUOTE]

This is always an interesting response but very rarely does documentation of “something special “ accompany the response.

if literature or evidence of a cop car 6bbl exists, it should be easy to post.

 

[Davea Lux]

It was NOT possible to order a fleet 440 6BBL Plymouth or a 440 Six-Pack Dodge, in 1969, 1970 or 1971.

If it was, please provide documentation.

If any were built its probably because someone knew who to ask to get the "non-available" equipment as with GM's COPO ordering options. Company executives could also probably get "something special."[/QUOTE]

I remember seeing one 6BBL cruiser at auction about 1973. May not have been sent out that way but it had the 6BBL under the hood. I am not sure but I think with the E-91 police engine package, it might have been possible to expand the engine choices outside of the normal offerings. Also possible the police fried the factory engine and dropped a 6BBL engine in the car for special high speed situations. At this late date I don't know any good way do find out.

Dave

 

[polara71]

If any were built its probably because someone knew who to ask to get the "non-available" equipment as with GM's COPO ordering options. Company executives could also probably get "something special."

I remember seeing one 6BBL cruiser at auction about 1973. May not have been sent out that way but it had the 6BBL under the hood. I am not sure but I think with the E-91 police engine package, it might have been possible to expand the engine choices outside of the normal offerings. Also possible the police fried the factory engine and dropped a 6BBL engine in the car for special high speed situations. At this late date I don't know any good way do find out.

Dave[/QUOTE]


Krautmaster on the Drydock ( did sign up here but never posted) always spoke of modifying cars while wrenching on state cars. The stories he told was like being there. Fabulous stories of stuff that never existed.

 

[shooter65]

Here is my opinion on the subject but I'm sure others here could correct mistakes I may have made.

Here is the info for the 69 SF, 70 SF/GT, and 71 SF/GT. I've attached 69 for reference to show the year before 70 also. The marketing and the fact that different 440's were offered throughout the different makes and models makes this confusing.

From Marketing, it usually was this: Plymouth: Commando = 350hp, Super Commando = 375hp. Dodge: (No named designation) 350hp, Magnum = 375hp, Chrysler: Firepower = 350hp, TNT = 375hp. The codes were E85 for 350hp and E86 for the 375hp. It gets really confusing, at least for the SF/GT in 70 because they marketed them as Super Commando, even putting a Super Commando pie tin on them but they were E85, 350hp. It does seem they may have had some higher perf parts then the other 440 4v that was used in other cars in 70 but it certainly adds to the confusion.

I've attached several screenshots of the Dealer Data books for all three years and the AMA Specs for 70.

1969, if you bought a Sport Fury with a 440, it was the High Performance 375 hp, Super Commando, you couldn't get the 350 hp 440 in the Sport Fury.

1970, The options were the E85 350hp and E87 390hp.

1971 Sport Fury/GT

 

[Bossssssss]

Wow - thank you all Men. Those are the details I was looking for. You guys are great!

Thank you again!
MArk

 

[rapidtrans]

“Regular-gas operation” for the 71 383-4bbl and 440-4bbl engines. The Premium fuel H.P. 440 was for Fury GT only and possibly the Chrysler 440 TNT.