Wallace calculator.
pretty much in lock step with PBR time and how they rated HP in 72.
Stock 340 dyno tests?
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pretty much in lock step with PBR time and how they rated HP in 72.
nice rumble
That dyno is known to be a little on the happy side imo.
Not exactly stock heads with a multi angle valve job and bowl cleanup.
Dont think there is enough cam to get it there at any rate.
The dyno derby one the heads weren't messed with IIRC. no porting or clean up.
"treated to a performance valve job by JMS Machine"
Open to interpretation I guess, but it isn't a stock type valve job. At least 3 angle possibly more. Either way doesn't make sense to do a 3 angle and leave the ledge without blending it into the bowl.
How To Resto-Spec Build A 340 Engine - Mopar Muscle Magazine
Check out the second part to building our resto-spec 340 Swinger engine for a 1970 Dodge Dart. Tune in for more details and photos only in Mopar Muscle Magazine
so not really 'stock'
340sFastback
Well-Known Member
Performance valve job means they at least did a little bit of blending into the bowl maybe even smooth out a little bit of casting here and there. Gasket match intake to head, nah they didn't do that.....
My completely stock 50,000 mile 1968 Formula S notch ran a best of 14.2 at I think 98 MPH. I am sure about the ET, not as sure on the MPH. It was a long time ago. The car had 3.23 gears and 185/70-14 radial tires and didn't spin at all.
Here are the specs of the 1968 340 GTS that ran in the TV series "Manix.
'68 340 10.5:1 cr
275 hp @5000 rpm
727 auto/ 3.23 rear gears
1/4 mile mid 14s around 95 mph.
According to various magazine tests of the day (1968).
Manix 1968 Dodge Dart GTS
(3 minute video)
'68 340 10.5:1 cr
275 hp @5000 rpm
727 auto/ 3.23 rear gears
1/4 mile mid 14s around 95 mph.
According to various magazine tests of the day (1968).
Manix 1968 Dodge Dart GTS
(3 minute video)
MidnightSwinger
Well-Known Member
This is probably the next best account after the magazines from the 60’s. If it was 98 mph and around 3,200 lbs that should be about right for ~275 crank hp.
340sFastback
Well-Known Member
My stock cam, stock head, standard bore original '69 340 X head ran many 14.0 1/4 mile times and one time dipped into the 13s (once - think it was a tail wind). Street radials, crappy headers with dents, 2 1/4 full exhaust with some crappy mufflers, stock choke exhaust tips, 727 stock like converter, 600 Holley and 323 gears full interior. I think I used to take the spare tire and jack out of the trunk air the front tires up a little bit. Hardly the ideal drag car but it was a strong runner compared to most other "stock" engines back in the day. It could fend for itself out on the street fairly well and no problem doing smoky burn outs.
.15-.20 of that is racing in Maryland. Then subtract for headers, carb change, and radial
Tires is a biggie with what is available now compared to over 40 years ago.
August 1969 Hot Rod Magazine dyno tested a 340. Stock, made 280 hp at 5500 rpm. That's engine dyno, not chassis. One of the very few motors, maybe only motor, that made more hp than the factory rating.
In the mid-1970s, my 65 Barracuda with a low compression 72 340, stock except for a Torker intake and 3310 Holley, 4-speed, 3.23 gears, street tires, ran consistent 14.10s at 99.
Switching from stock 340 exhaust manifolds to fenderwell headers got me down to 13.70s at 102.
In the mid-1970s, my 65 Barracuda with a low compression 72 340, stock except for a Torker intake and 3310 Holley, 4-speed, 3.23 gears, street tires, ran consistent 14.10s at 99.
Switching from stock 340 exhaust manifolds to fenderwell headers got me down to 13.70s at 102.
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harrisonm
Well-Known Member
I read somewhere about 10 years ago (probably Mopar Muscle Magazine) that the 340 came out in 68 which was the same year as the Road Runner. Ma Mopar was not about to admit that the new small block (at 320) had almost the same HP as the 383 in the new Road Runner (335). All I remember is that I DID read it in a magazine I trusted.
Ironracer
Gearhead
Tire size, gears, weight, those variances matter, No?
yes i used my specs e70 bias ply and 3.23s hi-way gears 14.3@97 mph not 3.91s or 4.10s
a strong 68 to 70 340 puts out 310 315 hp with the chit stock carb 330 335 hp with a non chit carb
If you turned slower then 14.5 you coudnt drive or got a weaker motor
340 A bodys turned mid 13s to 14.0 mph stock there is dozens of road test showing this as well what more needs to be said after 91 posts
time resign from this thread
Wallace Racing has a calculator for HP and ET based on inputs you provide. ET-MPH-HP Calculator
My 340 Formula S FB ran a best of 13.48 @ 105.38 pure stock with a A727, 3:55 gears, and H70x14 tires. This was essnetially at sea level in SoCal (OCIR, Lyons, Irwindale, Pomona, etc). The car weighed about 3200 and I weighed about 185 so total weight was 3385. Using the MPH/Weight estimator, I get 305.23 HP. This is the best estimate as using the ET/Weight estimator is a function of traction and ability more than engine power. Using [email protected] in the calculator yields 273.13 HP. If you put the 305 HP into the top equation which estimates ET and MPH, you get 12.99 @ 104.04 MPH. This is what a car should do with optimum traction and driving skill so it shows how much improvment is possible with the power you have.
Fun and useful information to play with.
My 340 Formula S FB ran a best of 13.48 @ 105.38 pure stock with a A727, 3:55 gears, and H70x14 tires. This was essnetially at sea level in SoCal (OCIR, Lyons, Irwindale, Pomona, etc). The car weighed about 3200 and I weighed about 185 so total weight was 3385. Using the MPH/Weight estimator, I get 305.23 HP. This is the best estimate as using the ET/Weight estimator is a function of traction and ability more than engine power. Using [email protected] in the calculator yields 273.13 HP. If you put the 305 HP into the top equation which estimates ET and MPH, you get 12.99 @ 104.04 MPH. This is what a car should do with optimum traction and driving skill so it shows how much improvment is possible with the power you have.
Fun and useful information to play with.
Swinger 340
Well-Known Member
Would like to add. The "DART" is well balanced with the 340, not just the "A" body, as in a Cuda. The extra trunk in the rear help with the Hook-ups. Not so sure about the "decent mileage" either, I drove my 69' Dart around the neighborhood yesterday and the fuel gauge looked like the minute hand on my watch. Sure was FUN!!!!! Sorry to say, Yes I am one of those, "once a month driver now", but still need my fix.
Swinger 340
Well-Known Member
The tack, chrome valve covers and chrome air cleaner makes the car faster. Those were our first Hi-Po add-ons.
Rat Bastid
Dunamis Metron
LOL, yep.
Don't forget the stickers. lol
Nick's Garage has a nice video of dyno testing a 1970 340 for a 'Cuda.
Engine made 335 HP initially. With tuning it pulled 340.2 HP and 345.7 f-p of torque.
Nick tested a modified 340 with E-brock heads, AirGap, Holley DP, Cam was 0.525" lift, Engine made 395 HP after 10 pulls and tuning.
My 340 for my '68 FB FS will be similar but with a Purple Shaft 280°/0.480" cam for more streatability. I would be happy with 340 HP.
Engine made 335 HP initially. With tuning it pulled 340.2 HP and 345.7 f-p of torque.
Nick tested a modified 340 with E-brock heads, AirGap, Holley DP, Cam was 0.525" lift, Engine made 395 HP after 10 pulls and tuning.
My 340 for my '68 FB FS will be similar but with a Purple Shaft 280°/0.480" cam for more streatability. I would be happy with 340 HP.
Yep , MPH is horsepower. E.T. is just E.T.
Most 340's were pushing 250-260 HP at the crank from MPH being posted.
Yours is a well tuned and sorted combo.
B3422w5
Well-Known Member
I raced my 1969 Dart GTS at Martin in 1972.
i bought it used for 1200 bucks.
it came equipped from the factory with 3.55 gears.
only upgrade was cheapie headers and glass packs.
it went 14.23@ 99 mph late that summer. Was my first ever track outing
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