AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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- Jan 19, 2014
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- 25,845
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350 hp out of a fairly stock 340
- Thread starter 273
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 25,845
- Reaction score
- 13,155
My mild 360, with OOTB Eddies, 11/1 Scr, a 223/230/110 Hughes cam, a 4-speed and 3.55s, dressed otherwise like yours, ran 12.9/106 in a 3650# pound 68 Barracuda, on the one and only run it ever made. That translates to 335hp.
That cam was 270/276 advertised.
Not a hope in hell are my stock Eddies plus the compression difference, worth 75hp.
I don't believe your engine is up to speed yet, unless your Dart is way heavy. To go 100mph at 3400pounds, the Wallace says you need 262 hp.
But at 3650 it requires 282 hp.
Trapspeed is very little affected by modest changes in street gearing.
There are many things that can be choking your power.
IMO
You're gonna need to do some hunting.
Start your own thread; there are lots of FABO members here willing and able to help you track it down. Your engine/chassis combo has the basic ingredients to get into the 12s. Start with the basics; Do a compression test followed by a Leakdown test.
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apples/ oranges . How about a 68 383 Roadrunner vs a 340 powered Roadrunner. Gears wouldn't matter 383 wins.
Mine were 10 for 10. 68-71's were it. the 72-73 were dogs. But I did have a stock 72 put a cam in, headers and a model j conv. and it went 12.90 with 7" slicks & 4.10 gear, Duster 3300 + 200 for me. And my 68 4 speed ran to 6500+, the only change was to a 750 carb. I never found one that was mechanically sound that wouldn't run. But I tuned them my way. And no damn 87 octane. I don't like the Wallace calculator I use the ones from Mopar in the 60's - 70's.
It wasn't "MY" comparison. I simply expounded on it.
...but I do agree with you.
Not saying this about you just in general.
I don't get how these calculators, or really how people insist that there the true measure of power not a dyno, you would need a dyno to validate the findings of the calculator, since the calculator findings is held in higher regard even so much to call dyno results as wrong there's no way to validate the calculators results, given the fact there's multiple calculators out there given different results and the not knowing how these calculators were formulated and verified it makes no sense to me other than use them as I assume they were intended to be use as a ballpark devise.
i'm guessing that these calculators came about through a large sample of drag cars over the years some with known dyno and weight results others probably most with guesstimation of power to weight and most cars set up well or extremely good getting the most out of less power.
bobscuda67
Well-Known Member
It's a 1970 block with KB dished pistons at zero deck.
I knew I would get beat up saying I thought the 275 HP was pretty accurate but lets see a dyno sheet on a totally stock 340.
Don't get me wrong, I like the 340's but I just don't believe some of the wild claims people make about them.
The calculators take basic simplified physics formulas and perform calculations based on highly idealized assumptions. For example they will typically assume no aerodynamic resistance. They don't take into account the effects of things like proper weight transfer, CG, etc. They assume your car is a point mass that is propelled by a constant fixed power level. Hence why they predict a 300 HP engine will get you in the 12s. If your car gets close to a calculator then you can be sure you have a very efficient setup.
Just ran my cars weight to power about 10:1 and got from high 11's to low 13's @ 108 mph, I'm fine if it's somewhere in the 13's.
Nope! Raced many of 383 RR's with my 340 RR Never lost to one. Although 440's were hit and miss. Even beat my buddies 70 1/2 Z28 about 1/2 fender. The Mopar boys should be proud. If anyone doubts me I can take them for a ride in my HEAVY 69 Cuda 340 auto. and a 4.10 Dana 60' all steel and a mild steel 6 pt. but I do have S/S front seats in it. It's a 340 .030 over 10.5 and a 540/520 cam and ported X heads.
all due respect
nhra rates the motors based it takes this much hp to run this mph at the rated weight
its not a wild claim its just the same as 1 plus 1=2
Some motors are over rated from the factory by all gm ford mopar
340 rated 275 nhra 295 to 315
383 rated 335 hp nhra 310
396 350hp over rated not going to look it up
426 hemi way under rated
mph and weight= hp pretty simple
mopar head
Well-Known Member
Di
didn`t they have an all aluminum 427 rated as much as the 426?
I don't know.
I do know that any big inch big block with good head flow can make a ton of power
mopar head
Well-Known Member
What I`ve read it was a late 60s vette engine. 426 was like a $500 extra option. the 427 was several thousand option with close to 13-1 compression.
That`s a lot of coin in the late 60s
who said it wasnt keep up
396 350 hp over rated hp wise 320 on a good day 396-325 hp was a dog
396 375 hp L78 not over rated hp wise over rated in the vette @425 hp cough bs cough
I grew up driving and riding in 396 12.5 to 1 280@50 580 plus lift 2 1/8 headers rectangular port heads tunnel ram 2 660s m-22 3.31 gears shifting @8000 rpm 3rd gear was over 135 use to get gas at the airport 5 gallon jugs
iam pretty sure iam aware
only the zL1 was 12.5 and L88
L71 72 98 11 to 1
harrisonm
Well-Known Member
I don't know about 4.10 gears, but in early 1969 I bought a new 69 Barracuda 340 Formula S 4 speed with 3.23 gears and NO options. Manual steering and brakes. The only mod I ever did was headers. I did a lot of street racing, and I can honestly say that I never lost to a 383 RR or Super Bee. Maybe I just happened to have a 340 that just happened to fall together perfectly. Maybe, since it was a fairly early 69, it had the slightly hotter 68 340 stick shift cam. I can only tell you that it ran like a bat out of Hell.
I can guarantee you a 68 383 S barracuda with hooker fenderwells will walk all over a 340 car.
4SPD/ 3.55 gears.
harrisonm
Well-Known Member
I won't argue that. I think the main reason a 340 A body does so well against the 383 Road Runners is the weight difference. I had always heard that the driver's side factory exhaust manifold was so restrictive that it really hurt performance. I bet adding headers to one of those back in the day would really have given you a big seat of the pants feeling.
I will
The toad runner 383 was over rated nhra lowered the hp of the 383 dog motor
nhra up the 340 to almost the same as the 383 and higher in the best version
the avg road ruuner was 15.0 the avg 340 was 14.5=sucking the paint off it
you see they want 4spds headers and gears to take the win but still lose
383 727 3.23 in anything cuda road runner is a 15s second turd
stock 340 727 3.23 14.3 97
340 727 3.55 700 dp 13.1 104 otherwise stock 15 cars no headers no 4spd
stock 383 cars were slowwwwwww in any body
wonderfull traction in that 383 4spd 3.55s with headers on e-70s worse 60 foot from stock maybe a 2.5 meanwhile the 340 3.23 car rips off a 2.00 60 foot 5 cars and turns a higher trap spd
about the same as a wheel hop gm big block on those tiny tires up in smoke 5 cars behind in 150 feet race overrrr
how many records does the 340 A- body hold many many
how many records does the 383 any body hold? crickets crickets zip
The ss 396 chevelle trapped 100 mph 400 gto 97 to 100 they also weighed more then a 383 b body the 383 with a 4spd and 3.55s trapped 94 lol
ford 390 mustang was a turd
340 was the baby hemi and smoked many many big blocks the 1st 100 feet the race was over
junkyardhero
Well-Known Member
the ZL1 "option" was $4700 in 1969 and supposedly only made it into two corvettes making them a jaw dropping $9500ish (base price was 4900). they did make them into 60 some odd COPO 69 camaros that were ordered with automatics for drag racing only, which again, tipped the scales at bit over 7K with that 4K option.
for comparison sake, that 4,700 is 38K in todays funny money.
Ironracer
Gearhead
The 383 Magnum / Super Commando was a Bad Mid size *****!
Ironracer
Gearhead
Ain't Sure if the Super Track Pak was around for the 383, but if I'm right, it was for the 69 1/2 440 6 Paks, 4:10 Dana and SS Springs. Kinda off topic, my Bad, as Usual!
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