NHRA rulebooks: '69 or earlier
 

Anyone have any old NHRA rulebooks? I've got '70-72, but am curious as to if '69 and earlier are pretty much the same. I'm betting they are, but just "curious". The part I'm interested in is the wording on the exhaust:

EXHAUST SYSTEM: Exhaust system must be equal to factory equipment per h.p. claimed. Dual exhaust pipes, with mufflers, are permitted. Headers are also accepted, but exhaust must be production type routed through mufflers and tail pipes. All mufflers must be production type and installed in the stock location - may be moved forward if original location was located behind rear axle - with tail pipes extending at least to the rear axle. The main body of any replacement muffler must be at least 18 inches in length. Open bypasses may be used, but mest be installed in front of the muffler and in such manner as to direct exhaust away from the strip, tires, and car body.

That's verbatim from the 3 ('70, '71, '72) book that I have...was it the same in '69? '68?

Thanks!

Re: NHRA rulebooks: '69 or earlier
 

Rob,
I have NHRA rule books all the way back to 1959. If you're specifically interested in the exhaust wording from the '68 & '69 book, I can check them tonight and let you know tomorrow. Unless someone else pipes up today.
Verne.

Re: NHRA rulebooks: '69 or earlier
 

I know that rule changed at some point because in the old pics you see some cars with tiny mufflers and pipes that were hung on the car just to meet the rules. They were small light parts and were not connected to the headers as the rules allowed open headers. Then at some point they changed the rule to where you had to have more of a stock looking ex system.

An afterthought
 

Rob,
What class are you interested in.........? I'm guessing Stock, since Pure Stock doesn't allow headers, and Super Stock didn't require a full exhaust system.
Verne.

Re: An afterthought
 

Yeah, stock is what I'm after. Just curious when, and how long, the exhaust rule was in effect.

Re: NHRA rulebooks: '69 or earlier
 

Rob,
I looked back as far as my '65 book.
Results:
'69 had the exact same wording except for a 3 1/2" outlet size limit on the exhausts, rather than 4"
'68 the same. They also grouped stock and Super Stock under the same exhaust rules.
'67 Same as above
'66 Same as above
'65 Same as above

I didn't look back further, but I know in '63 you could still get away with any tiny muffler and pipe. The wording did not specify an exhaust as per the original horse power rating of the car. But from '65 up, it did.

Hope this is what you were looking for.

Verne.

Re: NHRA rulebooks: '69 or earlier
 

What did a Z-11 come from the factory with ? 63 SD Catalina swiss cheese came with a tiny single exhaust and those gorgeous exhaust manifolds with dumps.

Re: NHRA rulebooks: '69 or earlier
 

Thanks Verne! Someone also emailed me off line and said that they rules almost identical until 1974.

Re: NHRA rulebooks: '69 or earlier
 

I think the Z-11s came with a stock exhaust system with cast iron headers from the factory. They may have been a special cast iron header? [img]/ubbthreads/images/graemlins/dunno.gif[/img]

Re: NHRA rulebooks: '69 or earlier
 

Verne:

That helped a lot! One last question: was there a compression ratio rule? It's my understanding that currently you have to be under the advertised cr, but was it that way prior to '74?