Pure stock 340 Mopar
 

Just wondering if anyone is running the 340/275 (AVS) in Pure Stock? Some time ago I remember someone running a '71 Demon 340/275 (TQ) as a Pure Stocker, and would appreciate any info I can glean.

I may initially build my '69 Dart as a Pure Stocker to get my feet wet in our local Stock/Super Stock series, then work my way up ($$$$$) and build it as a traditional Stocker.

Re: Pure stock 340 Mopar
 

I have a '70 340 Dart Swinger that I run in Pure Stock. I can help out as much as possible, though my experience is limited. I didn't run last year, and only once the year before. limited time and resources lately. I just went through it last year so I hope to run a little more this year. I barely run the index, but I built everything myself.
PM me and we can talk.
Mike

I run D/PS, have run under 3914 and 5914

Re: Pure stock 340 Mopar
 

In pure stock, you must run manifolds and polyglas tires, no port work of any kind, 2 1/2 exhaust with H or X pipe

Tom cannon runs a 71 with that carb in pure stock

Re: Pure stock 340 Mopar
 

1971ls6: I believe you're referring to the "Pure Stock Musclecar Drags" series in which you must run manifolds and bias tires.

Mark: IHRA has a Pure Stock class that NHRA doesn't. Our local series runs under IHRA rules which open things up to more participation from 'different' classes. You can't use a 'stocker cam' as a traditional stocker can. But I've read here that you should have a cam ground which will check within the specs but should work better than a dead stock grind.

Can run headers with mufflers OR open manifolds.

You can check out the rule book at http://www.ihra.com/.

Thanks for the replies guys.

Re: Pure stock 340 Mopar
 

Correct on all the above. You can run 9 inch slicks at 29.5 diameter. The cam MUST check on OEM duration and over lap like in the Jr. stock days of pre 1972. The valve springs must check on OEM open and close pressure specs also.
Just pretend your racing back in 1971 Jr. stock days if your old enough to remember those days.

Re: Pure stock 340 Mopar
 

Is there a list of the current Pure Stock records?

Re: Pure stock 340 Mopar
 

Jerry Coblentz from eastern Ohio runs a Demo in C/PS, I believe it's the 340/275. I'm unsure of the IHRA rating, I think it's 310.

Re: Pure stock 340 Mopar
 

Mark, I already have a set of 1 3/4 non-step headers, will I be able to get away with using them with the X pipe and mufflers ??? I'm only 43 also !!!

Re: Pure stock 340 Mopar
 

Todd,
I have been running 1 3/4 headers on mine with flow master mufflers.
I don't have a cross over pipe. My thought was run the larger pipes since the muffler was required and will create some back pressure.
I haven't done any additional testing with smaller hearders or X pipe.

Mike

Re: Pure stock 340 Mopar
 

The worst part of this whole deal is that I just sold a set of Hooker 1 5/8" street & strip headers that I think may have worked with this combo. The main reason I'm wondering if the 1 3/4" will work is that I already have them, and will run them when I eventually build the car into a traditional stocker.
Like Mike, my thoughts were that I could get away with the larger pipes with the exhaust system creating at least some back pressure. Mark, I know you're the man for headers, so in all honesty, what kind of ET difference can I expect between the 1 5/8 and 1 3/4 pipes?
For our local series, I'd be really happy to be -.2 or .3.
I used to run my street/strip '69 Dart with a very mild 360, 904 with 3400 stall converter with 4.10s on 26" slicks. It went a best of 12.9 @ 105 (it was a street and strip car). The car had full exhaust including tailpipes and OLD Dynamax mufflers.

Re: Pure stock 340 Mopar
 

I had planned on building a 340 to run IHRA pure stock with my 1969 Barracuda street car. The Crandall track closed, so that plan went out the door. I had bought a custom cam from Bullet for that deal, it was something like 250 degrees at .050" on a 109 LSA as I recall. The old factory spec for the 340 cam was something around 336/348 duration at .000" lift, so that gave a lot of leeway in grinding a cam. Not much different from the regular stocker cams from what I know about them. I also have an old Lunati(c) cam and an ancient CD stocker cam from the 1970s that I was going to try. I liked the idea of Pure Stock since I didn't need to put a rollbar in an original 340 car.

Re: Pure stock 340 Mopar
 

Hi James.
That sucks about your track closing.
On the factory spec cam do you mean the "stock eliminator cheater cam" with 336/348 duration at .000" lift that Mopar had, or are you referring to a factory 340 cam ? I didn't think the duration was that long on a factory 340 cam.

I'm wondering how much a custom cam will be worth.

Re: Pure stock 340 Mopar
 

Todd, what A56 is talking about for the exhaust is that it's not the back pressure the system gives to the engine, but the velocity at which the exhaust gases have to travel in a smaller primary tube. The higher velocity (or rate of speed) will help to draw (or scavenge) the air/fuel into the cylinder during that minimal overlap period, effectively cheating the engine into thinking it has more cam duration. On the monte we ran small primary street headers (cheapo flowtechs) that achevied this, but with a 3" system and mufflers to not create excess back pressure. It went .4 under with a 100k mile engine.

Re: Pure stock 340 Mopar
 

Todd,
The cam specs come from the NHRA / IHRA engine specs. For the high compression 340's, the specs have the 330 ish duration. They don't match the "advertised" specs. I think Danny Waters Sr. may have the specs. Terry Bell used to have them, but I don't think he does anymore.
They have to be the old specs from before they removed the duration requirements, from like 20 years ago. I have them for the '70 340. I am not sure if they are the same for the earlier ones.
I have an ISKY stock grind that is around 348 @ .050. with .478 lift I think. It is the dwell nose type. The higher lift works because I run the stamped rockers and the ratio is off from the 1.5, so the actual lift at the valve is still a little short. It is supposed to be a good cam for a regular stocker, but I think it is too much for a pure stock. I run stock valve springs per the rules and I only get 6200 - 6300 rpm. If I were to get another, I would get one that works more to that rpm range.
Some time ago, I talked to the guy with the pure stock demon. I think he was only shifting @ 6000 and 4.56 gears and he was running around 12 flat. I don't know what his specs were. But as I said, I built my engine and I think he had someone build his. I know there are probably several items that could be improved on mine.

Mike

Re: Pure stock 340 Mopar
 

I WOULD GUESS only a few hundred between productionheaders of the two sizes.. I have run the Flowteck 1 5/8 from summit on 318 or 360 engine and they were not bad and only $119 at that time. Of course Mark's Perf. Welding are much faster than any mass
produced piece!

Re: Pure stock 340 Mopar
 

Thanks Chipper, I'm beginning to figure this all out. You want velocity, but not back pressure. Did you use an X-pipe or H-pipe with your 3" system ? What class were you running ?

Re: Pure stock 340 Mopar
 

John, did you run the Flowtechs in an A-body? I'm wondering how they fit?

Re: Pure stock 340 Mopar
 

I still have the Dodge specs up to around 1973. Dont forget that in Pure stock you are supposed to run the OEM type trans that came with the engine combo that you are claimming. No manual valve bodies either but I know of a few who are cheating and geting away with it using a 904 instead of the 727. Early 340's are suppposed to use a 727 Torqueflite and NOT the 904. No back cut on the valves either unless it was factory like the 455 SD Pontiacs and newer Vettes, etc. 99.9% of the current tech guys wont know the difference so if you have no morals go for it.

Re: Pure stock 340 Mopar
 

Terry
I do run the 727, but have a manual valve body. When I was putting it together, there was a debate on this and I believe Dwayne said it was OK.
there was also a debate on the transmissions and at the time, it was worked out that if you ran a 904 (or any non original trans in other brands) you had to use the current HP rating, but if you ran the original (727, etc) you would get a 10 hp reduction for carbs (5 for FI cars).
Like I said earlier, I haven't raced for awhile so I don't know if anyone still uses this, but it was never made official and I still use the rated hp because of that. So I am at a disadvantage due to that....plus my valves are stock with no back cut...probably why I only run .1 to .2 under, among other things...
Mike

Re: Pure stock 340 Mopar
 

Todd,
I ran my '72 Cuda in Pure Stock for several years.I set a couple of records early on and went through teardown with the old stocker style cam.(I actually had an old cam I bought and used from Ed Hamburger back in the early 80's).
The 904 was run in my car after a call to Mike Baker at IHRA.I asked if the 904 could be used in place of the 727.He asked me if it was the same number of forward gears(to which I answered yes) and he told me it was fine to run that transmission.
At Norwalk in 2005 when I qualified #1 in Stock is when some turds hit the fan. It was then decided to let the cars with the stock trans have a 10HP deduction. We were several times checked to see if we had the mechanical fuel pumps,as were others. The rear tire size is limited to 29.5 and when Mickey Thompson came out with the 29.5 radil slick we used that.Truman Fields actually ran the 29.5 Mickey radial before anyone else because he was testing the tire for M/T.We could not yet purchase that tire.
I ran the Hooker 13/4 Super Comp headers with Flowmaster mufflers with turndowns right off the end of the mufflers.
I decided to step up to Stock Eliminator with the associated cost of a 10,000 engine,$4700 Transmission,and $2700 Headers (from Mark and worth the money).Pure Stock is a great place to run and very cost effective. All of the S/SS associations around our area let these cars run as they are a part of IHRA Stock Eliminator.
I am putting together an '80 Aspen 318 4bbl.car for Pure Stock and local brackets.The 318 HP combo uses many of the same parts(heads,cam ect.) as the 340 and 360.
Good luck with your car.
Jeff Ross
IHRA G/SA 313
NHRA F/SA 3313

Re: Pure stock 340 Mopar
 

I've been using TTI 1 5/8"-1 3/4" step headers for many years. After the first couple of years of tuning, I added the TTI 3" X-pipe and Dynomax Ultraflow mufflers ending at the rear housing. After removing the extra 60-70 lbs the exhaust system added from elsewhere in the car and a little more tuning, the car was between .05 and .10 faster than the best I could get with their open header and collectors.

I may try the Dynomax bullet-style mufflers at a later date to save weight and have more room around the differential. But I don't know off hand how specific the IHRA Pure Stock rules are pertaining to mufflers for your application.

Re: Pure stock 340 Mopar
 

Terry, any chance I could get a copy of the '69 340 specs from you? Seems it would help considerably with cam choice.

We don't have any IHRA races close to here and I'd only be running the car in our local series, so I don't think they're gonna mind my 904. I'm trying to do this on the cheap (if that's even possible) and use as many parts as I already have, although it seems I now have to buy a set of small headers cuz I sold my old 1 5/8" ones last year.

Re: Pure stock 340 Mopar
 

No problem. One thing...I just read the rule book for 2011 AND 2012 and on page 55 of the new rule book under "Transmissions-Automitc it reads .....MUST be stock OEM for horsepower and body style claimed. (That means NO turbo 350's or 200 metrics on GM cars that came with 400 turbos.....same deal on Ford C6's vs C4's) May NOT be altered except for addition of aftermarket shift kit. (That means NO manual valve bodies for those who cannot read.) Aftermarket converters allowed " Regardless of what Mr. Ross says this wording has NOT changed since I wrote the rules many many many years ago. If Mike Baker said OK to use what you want....so be it but it is not in writing so I suggest you contact Mike Baker directly nor does it affect me in any way. Also the HP reduction or addition for using a lite weight trans is also NOT in the rule book. Its been appprox 10 years since I left IHRA so who knows what what was said or not. Everyone knows the 904 is much quicker than a 727. The intent of the class was to build a combo that closely resembled pre 1972 "Jr.stockers". Take it for what its worth.
1969 Dodge Dart specs as follows:
63.3 Head C.C.'s
deck .045 above block
head gasket .035
Flat top piston with -5.45 cc valve relief
Valve springs Intake & Exhaust 111 lbs on the seat and 240 lbs open pressures both have a damper
Valve size: Intake is 2.080 diameter with a 3/8th stem
Exhaust is 1.600 again with a 3/8th stem
rocker arms are stamped steel with 1.5 ratio non adjustable (shimming required for rocker adjustment in ALL non adjustable rocker systems or adjustable push rods are allowed)
intake manifold number 2531915 cast iron
Carb #'s carter AVS # 4611 or 4612
Intake duration at .000 checking clearence is 336 degrees Exhaust is 348 degrees also at .000 checking clearence
cam over lap is118 degrees
Lift is .459 for the intake and .443 for the exhaust checked at the retainer.
OEM oil pan required but internal mods and baffels allowed
No +.013 crank stroke like on the regular stockers allowed
The water pump must be crank driven as per OEM with OEM pullys and must have a fan attached to water pump pully.
Originally the rear was OEM only but because of todays tire technology any MoPar rear is allowed to up grade for strength such as a Dana 60 to keep the parts INSIDE the housing and off the track. There is no wording on if a posi must be used or a spool is allowed. Your choice.
Hope this helps.
Terry

Re: Pure stock 340 Mopar
 

Does IHRA allow a 2.08 intake valve in the 340?

Re: Pure stock 340 Mopar
 

The specs are below.

Re: Pure stock 340 Mopar
 

My bracket 95 camaro has a stock motor/transmision but it has a roll bar is that allowed in pure stock.

Re: Pure stock 340 Mopar
 

That does help greatly Terry, it's much appreciated. I'm thinking the intake valve should be a 2.02 though as that was the largest valve available in a 340.

Re: Pure stock 340 Mopar
 

I think the current NHRA specs for a 1969 340 still apply to Pure Stock. The cam lift is higher on the exhaust. I think the service manual lists it as .429"/.444" or something like that, but Chrysler fed NHRA some enhanced numbers way back when.

HP Disp Deck Cl. Valve notch Int./Exh. Valve Cam lift
275 340 DP .045ab Flat w/n 5.45 cc 2020/1600 462/473 .035 Outer w Damp

Re: Pure stock 340 Mopar
 

Yes its 2.02......That was a typo. My falt, Sorry. I should have proof read it closer.

Re: Pure stock 340 Mopar
 

Yes...Its considered a safety item.

Re: Pure stock 340 Mopar
 

I have 2 sheets of specs. The one dated Feb 1969 lists the lift at .467/.473 in one book.The duration is the same. The other sheet in my other book I have is dated the same Feb. 1969 but lists the lower lift . Go with the higher one. Chrysler did some funy things back in that era. Its good that you caught it.
Thanks.

Re: Pure stock 340 Mopar
 

Also have to keep back seat in pure stocker w/roll bar,I had to put mine back in which I like it better with it anyway
Mike Taylor 3601

Re: Pure stock 340 Mopar
 

Todd, I had the monte set up for g/ps. No x pipe or h pipe. It's my beleif that an x pipe would help if you have cheaper, non-equal length primarys. I never got the time to play with it on the monte. Spent too much time playing with the q-jet! Even though you're running a stock cam, a "healthy" converter will really help that low po (by comparison to a true stocker) engine get the car going wink wink.

Re: Pure stock 340 Mopar
 

Ihra Pure Stock

So, roll bars as a safety item is OK , would weld in frame connectors be allowed to tie it all together?

Steve

Re: Pure stock 340 Mopar
 

I can't see frame connectors being a problem, I'm putting them in without a roll bar, but we should wait for Terry to chime in here on it.

Re: Pure stock 340 Mopar
 

Terry, I see in the 2012 rule book that 9x30 tires are legal as well as "accepted aftermarket" ignitions. Would those include like a MSD 6AL for example ?

Re: Pure stock 340 Mopar
 

9x30 tires? Does that include radial slicks? I showed up once at 42 with a set on my Camaro and was told to 'make sure that they were off the car the next race I went to".

Re: Pure stock 340 Mopar
 

Its been 10 years since I delt with any of this. I heard they increase the tire diameter to 9X30's. In the beginning many years ago only 9X28.5 was allowed so the fender well lips would not have to be "Massaged". Tied frame members were allowed early on. You might want to contact Mike Baker, Hank Blankenship, or maybe Danny Waters will jump in here. Electronic ignition conversions are allowed but the OEM distributor must be used. Again I would check with Mike Baker or one of the other guys still working.

Re: Pure stock 340 Mopar
 

Cool, thanks Terry.

Re: Pure stock 340 Mopar
 

The flowtechs do not fit good at all, they hit the T bars and other places, i ran then on A body for about a year took them off and intalled Hooker super comps, the fit and performance is very good.