72 340 actual hp?

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tarrin8

tarrin8

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hey i was just wondering what the actual hp of a 72 340 was?
i know the 71 340 was rated at 275 but i herd it was actually ~330 so the 72 was rated at 245-250 what is the actual horsepower? or did they tell the truth on this one.

i am just wondering because i bought a car with a 72 340 and its getting shipped to me right now, so i just want to know what to expect for horsepower and yes the motor is completely stock.
 
Allot less 1972 was the year 340's lost 10.5 to 1 compression ratio in favor of 8.5 to 1 for emission considerations. It also picked up the 360 head with smaller intake valves. And was phased out by the 360 four barrel in 1974. The 360 four barrel 74-76 is the last of muscle installed in Dusters and Dart Sports. The 72 you bought can be built to almost early spec.'s but it will never be exact production numbers. And the 340 6 Barrel was a whole different engine. I wish I had one, used too long ago. They were built with a special thick web block, specially machined heads, adjustable rocker arms and the unique carburetors and intake manifold. That engine was the LA peak performer, hope this helps.
 
There is a link at the top of the page that will take you to e body forum's!
 
I just looked there and didn't see one T/A for sale, that is the peek performer package!
 
Also a thing to remember is that in 1972, the way engines were rated changed. To put it bluntly if there were no changes to the engine other then the rating (HP level example 30hp) then this is what the 1971 engine were truly making. So don't always believe the hype that 1972 was a massive loss of HP.
 
1970Duster said:
Also a thing to remember is that in 1972, the way engines were rated changed. To put it bluntly if there were no changes to the engine other then the rating (HP level example 30hp) then this is what the 1971 engine were truly making. So don't always believe the hype that 1972 was a massive loss of HP.
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Right, this car was most likely the car that was pushing 330HP. Damn that is a sweet ride. I think the only other E Body I seen that looked this good is a convertible T/A Challenger http://cgi.ebay.com/ebaymotors/1970...t=US_Cars_Trucks&hash=item3a6a13c865:toothy1:
 
65CudaFish said:
Right, this car was most likely the car that was pushing 330HP. Damn that is a sweet ride. I think the only other E Body I seen that looked this good is a convertible T/A Challenger http://cgi.ebay.com/ebaymotors/1970...t=US_Cars_Trucks&hash=item3a6a13c865:toothy1:
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The convertible Challenger T/A would have been a "tribute" style car since T/A's and AAR's were not available with a convertible. But the styling and graphics were among the best Mopar ever had, along with many models from the '71 line-up.
 
Locomotion said:
The convertible Challenger T/A would have been a "tribute" style car since T/A's and AAR's were not available with a convertible. But the styling and graphics were among the best Mopar ever had, along with many models from the '71 line-up.
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Cool I seen one at Hot August Nites in Reno, it was great looking. The only other one (convertible) I seen is just a regular one. It is pictured in Chrysler Muscle/Detroit's Mightiest Machines by Bill Holder and Phil Kunz. Great coffee :coffee2:table book.
 
no changes ?? 10.5:1 down to 8.5:1 compression , cast crank , that must have done some damage .
 
what it actually was and what it said on paper are two different things. even the 10.5 to 1 motors weren't actually 10.5 to 1 because of the sloppy *** machine work that was don't on the motors. go knows where legit hp was. hell we did a 383 a few years ago and one side of the deck was 15 thousands higher then the other. this was an original owner car. the motor was never out of the car. i bet the ***** was lucky to be 9 to 1.
 
jerry6 said:
no changes ?? 10.5:1 down to 8.5:1 compression , cast crank , that must have done some damage .
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Yeah it did, the compression ratio that is, the cast crank was in the 1973, I don't think it was in the 72 maybe late ones. But the cast crank was actually better then the steel one back then. It was said to be the nicest balancing on the circuit at the time. But today, I would go with a steel eagle from Mancini Racing and H beam rods. Some of the old MoPar steel cranks were badly forged and balancing holes were drilled everywhere some would not seal without rope seals and in some cases more balancing. But strong yeah! Lighter no! And much harder on rod end play wear. Today's technology is great, it just cost a fortune. :burnout:The 340 I had along time ago was factory except for the headman headers and it had to be timed at 1 degree ATDC in Southern Cal. because of the compression ratio and would top at 135 MPH with that timing, but man did it get there quick, it was a 1970 model.
 
65CudaFish said:
Yeah it did, the compression ratio that is, the cast crank was in the 1973, I don't think it was in the 72 maybe late ones. But the cast crank was actually better then the steel one back then. It was said to be the nicest balancing on the circuit at the time. But today, I would go with a steel eagle from Mancini Racing and H beam rods. Some of the old MoPar steel cranks were badly forged and balancing holes were drilled everywhere some would not seal without rope seals and in some cases more balancing. But strong yeah! Lighter no! And much harder on rod end play wear. Today's technology is great, it just cost a fortune. :burnout:The 340 I had along time ago was factory except for the headman headers and it had to be timed at 1 degree ATDC in Southern Cal. because of the compression ratio and would top at 135 MPH with that timing, but man did it get there quick, it was a 1970 model.
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One thing is for sure that much compression dropped killed the power it was designed to originally have with the bigger valves.:wack:
 
abodyjoe said:
what it actually was and what it said on paper are two different things. even the 10.5 to 1 motors weren't actually 10.5 to 1 because of the sloppy *** machine work that was don't on the motors. go knows where legit hp was. hell we did a 383 a few years ago and one side of the deck was 15 thousands higher then the other. this was an original owner car. the motor was never out of the car. i bet the ***** was lick to be 9 to 1.
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I agree with you, some MoPar's were great and others failed quickly. MoPar was noted for experimental work for sure. But that's why us gear heads and wing nuts love em. Sometimes it's what is it going to take, a bigger hammer:fart:
 
abodyjoe said:
what it actually was and what it said on paper are two different things. even the 10.5 to 1 motors weren't actually 10.5 to 1 because of the sloppy *** machine work that was don't on the motors. go knows where legit hp was. hell we did a 383 a few years ago and one side of the deck was 15 thousands higher then the other. this was an original owner car. the motor was never out of the car. i bet the ***** was lick to be 9 to 1.
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Well my stock 1970 340 makes 350 hp 375 torque , my other 1970 412 hp 391 torque with cam air gap pistons heads ported block zero decked , balanced , set up very well . . Stock had the cam changed , not sure what was put in , maybe factory replacement , everything else is how it left the factory except headers .
Yes it was sloppy back then , but if they reduced to 8.5.1 then it made a difference , say 9. 5 high , 8.1 low ? Lucky if you got a good one . I can tell you had a buddy with 74 318 and my 74 318 his would smoke mine , same car same equipment . If we traded cars I would smoke him . Areal crap shoot back then !
 
65CudaFish said:
Yeah it did, the compression ratio that is, the cast crank was in the 1973, I don't think it was in the 72 maybe late ones. But the cast crank was actually better then the steel one back then. It was said to be the nicest balancing on the circuit at the time. But today, I would go with a steel eagle from Mancini Racing and H beam rods. Some of the old MoPar steel cranks were badly forged and balancing holes were drilled everywhere some would not seal without rope seals and in some cases more balancing. But strong yeah! Lighter no! And much harder on rod end play wear. Today's technology is great, it just cost a fortune. :burnout:The 340 I had along time ago was factory except for the headman headers and it had to be timed at 1 degree ATDC in Southern Cal. because of the compression ratio and would top at 135 MPH with that timing, but man did it get there quick, it was a 1970 model.
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Castcrankdebut.jpg
 
dmoore said:
Castcrankdebut.jpg
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Wow even 1972. I heard that they all were cast in 1973, looks like most were in 1972 as well, they just used up the engine stock they had left over from 1971. They would have to, or eat a whole lot of money. Which makes since just drop the piston down in the bore a little and there it is lower compression use them up and all the other parts and then put the cast crank engines into full production, sounds logical.
 
Jerry says his is 350HP with headers not sure of the carb set up. The 1969 motor manual I have rates the 68 & 69 at 275 with the 4 barrel. I can see 350HP with cam headers and 650CFM-750CFM induction. A friend of mine in Reno asked me one day why his 340 Cuda would not light up the tires and I said let me see the engine. He opened the hood, and I said Hooker Headers in Ontario Cal. will get your tires spinning. The next time I seen him he had them on it and it was spinning the tires with ease. That is a known fact, that MoPar had the siphoning restricted exhaust systems, the 340's being the better of all, but still headers open any small block MoPar up to it's real potential. So A 6 Pack set up with headers is like 1050CFM opened up it would be like a 440 with stock exhaust 375 + HP. The rating for the 72 is 240HP in stock form with a 4 barrel maybe 575CFM-625CFM, with little effort like said here it can get to 300HP easy and thats with 8.5-9.1 compression, cam induction & headers.
 
Factory ratings were bs back then , that or they took the last motor built on Friday before labour day week end
 
'72 340's had a 750 Thermoquad. I believe they went to 850 on '74 360's.
 
Locomotion said:
'72 340's had a 750 Thermoquad. I believe they went to 850 on '74 360's.
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Wow! open that up and your in business then. I have a 770 holley on mine and it is plenty, but I really want a 4 corner Barry Grant 800:burnout:
 
65CudaFish said:
Wow! open that up and your in business then. I have a 770 holley on mine and it is plenty, but I really want a 4 corner Barry Grant 800:burnout:
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Yeah the 6 Pack was well above 1000 CFM and I know I have read that there were some ThermoQuads that were up to 1150CFM on the Highway Patrol Cars.
 
I read a comparison article of a 1957 Poly 318A engine dual quad set up and it said that it had as much HP as the 375HP 340 6 Pack. So that says allot for the 340. It was a creditable article.
 
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