Pure stock 340 Mopar

[1971ls6]

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

[Todd Boyer]

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.

[X-TECH MAN]

Originally Posted by Todd Boyer

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.

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.

[KRatcliff]

Is there a list of the current Pure Stock records?

[Todd Boyer]

Originally Posted by A56

Not old enough, im only 43. You need to put a small header on the car to draw as much air into the engine with a cam like that, your lucky though the 340 had a pretty decent cam though. 1 1/2" - 1 5/8" - 1 3/4" Merge Collectors to dual 2 1/2" with an X pipe. Maybe that will be of some help. Sounds like a fun class, wish I had the chance to give it a go.

Mark Lelchook
F/SA #704

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 !!!

[mike coates]

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

[Todd Boyer]

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.

[James L Miller]

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.