Pure stock 340 Mopar

[Myron Piatek]

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.

[Todd Boyer]

Originally Posted by X-TECH MAN

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.

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.

[X-TECH MAN]

Originally Posted by Todd Boyer

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.

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

[Peter Ash]

Does IHRA allow a 2.08 intake valve in the 340?

[X-TECH MAN]

Originally Posted by Peter Ash

Does IHRA allow a 2.08 intake valve in the 340?

The specs are below.

[Frank B.]

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

[Todd Boyer]

Originally Posted by X-TECH MAN

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

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.

[James L Miller]

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

[X-TECH MAN]

Originally Posted by Todd Boyer

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.

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

[X-TECH MAN]

Originally Posted by Frank B.

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

Yes...Its considered a safety item.