PSMCDR...new "tech"

[Rowdy Rat]

Ray,

I agree with you completely on this topic. The burden of proof for this combination lies with the owner and currently, I am unaware of any documentation which confirms that any 1968 L-89 Novas were built. I also have my doubts (as it seems you do) about the 311 1969 L-89 Novas supposedly built. I'm afraid it's too much of a coincidence that the exact same number of 1969 L-89 Camaros were built and that the engines carried an identical broadcast code. While rare, you would also think that a few documented examples would have surfaced by now (L-89 Corvettes, Camaros, and Chevelles have); I am not aware of any at the present time. Anyone else know of one?

As far as the L-89 heads (casting 3919842), you are correct again Ray. The heads have a few changes that improve performance over the 840 heads normally used. A pair of 842 heads are typically about 72 pounds lighter than a set of 840 heads which will certainly help with weight distribution. The exhaust valves are 2.19/1.84 (vs. 2.19/1.72 in the 840) and the intake port has been slightly revised to improve port flow. In addition, I believe the chamber volume of the 842 head is a bit less which should bump the compression ratio somewhat (going from memory on this one - will verify this). Obviously, the 842 heads offer several advantages over the 840s.

If anyone has additional information on L-89 Novas, I'd love to hear about it!

Regards,

Stan

[Chevy454]

Very interesting, Ray! So, anyone have proof of ANY L-89 Novas? I wish someone would find proof of the aluminum heads on the L-72s, as I would LOVE to run them on my Chevelle!

Dad's Camaro, the best we can tell from talking to the previous owner, other people who knew the car, and other people that know about Francis Chevrolet and lived nearby, came with aluminum heads. I seriously doubt GM did it, but somewhere along the way before the first owner got his hands on it, it had aluminum heads put on it. And, naturally, he had problems with them. We have talked with a guy who knew of another Francis Yenko Camaro that had aluminum heads, and had the same problems. Not only did the heads give them problems, but Francis wasn't too eager to warranty them. Frank Radake said Francis gave him the "run around" on warranty claims for his car as well.

The original owner of our Camaro said it was a pain to get his car fixed, as they told him at the dealership it had "special" heads on it, and they would be expensive to fix...they woulnd't warranty them! So, the car sat for 6 months before a zone rep finally came and had Francis fix the car.

[bowtie3168]

Stan,
I know that 311 1969 Camaros were built with the L-89 option, but I was unaware of the 311 1969 Novas. I found out last night that I was wrong in my comment about the L-89 1968 Camaro, Chevrolet built something like 272 of them. I agree with you that the 311 # for both models sounds odd. I would like to find out more info before I assume that it is real.
Andrew

[StealthBird]

I can fully understand the reason for teardowns. Anyone that has raced (or knows someone that races) in a Stock Eliminator class knows that these racers can find 100 ways to œbend the rules”. At the Pure Stocks, solid lifter cars can easily have NHRA cheater cams, getting 50+ hp over the factory grind. On hydraulic cammed engines, the use of a hydraulic roller cam is virtually undetectable, and can produce another 50 ft lbs of torque with a substantial increase in hp. Only the owners know whatÃs in their own engines, but they seldom relay that info to anyone else. AllÃs fair in love and drag racing.

Since teardowns were never performed at the Pure Stocks, someone could easily build an engine using the lightest aluminum connecting rod (and pin) available, lightweight racing pistons, custom crank, and a roller cam. With less reciprocating mass, youÃll have an engine that will rev like your hitting it with a 50 hp shot of nitrous, and in conjunction with a roller cam, these œstock” engines can pump over 100 hp more than what they had off the showroom floor. Of course, the owner will just shrug his shoulders claiming ignorance as to why their car runs so fast.

Because of all the hype and press given to the winners of the Pure Stocks, itÃs inevitable that people would begin to build œpurpose built” cars from the ground up to win this event (just like the Nova SS was that won the 1999 Pure Stocks). Odd, because there was no prize money offered, but some people will spend an outrageous amount of money simply to have bragging rights. Those of us that are more œseasoned” Musclecar fans quickly realized that 69 Nova SS 396Ãs did not run low 12Ãs on street tires in stock trim. Quite the contrary, as some original 1969 magazine tests claimed they were disappointed at how the SS 396 Nova performed, and one magazine went as far as to call it a œpig”. They were fast, but not quite the 3000 lb. big block terror that people expected, and usually ended up running in the 14 to 15 second range off the showroom floor.

One thing that bothers me though, is that on some powerplants (most notably Pontiacs and Mopars), a very slight amount of head porting can increase swirl and cylinder filling substantially, increasing low lift flow, and that can be virtually undetectable in a teardown. Grind marks can easily be covered up, and unless the person doing the teardown has an intimate knowledge of that particular cylinder head, cheating can and will occur.

I like the idea of a teardown at the Pure Stocks, but people will still find ways to skirt the rules. The bottom end of an engine can have a multitude of race parts that will be undetectable. ItÃs sad I know, but even professional NHRA racers are caught cheating every once in a while. Because of this, itÃs very hard to accept the etÃs these Pure Stock cars run, but itÃs indeed fun to watch! I, for one, applaud Dan Jensen and Bob Boden for their efforts, and love seeing the results, and wide array of Musclecars represented every year. My only œbeef” with the Pure Stocks is that IÃve run across a few people that take the etÃs these cars run as gospel, and think thatÃs what these cars were capable of running back when they were new.

I agree that dealer prepped cars should have their own class! It would be a blast to see a Baldwin/Motion 454 Camaro running against a Fred Gibb prepped ZL-1 Camaro, or a Royal Pontiac prepped 69 RAIV Firebird running a 69 Yenko Camaro. Most of the rules could go out the window with these cars because of the different levels of preparation and equipment the dealers used, but it would be great to see them running in their own separate class at the Pure Stocks.

[YENKO DEUCE REGISTRY]

I agree that Dan and Bob are doing a great job with this event, and I really enjoy going to it. The teardown thing would be frustrating for me, but I will consider doing it.
M

[bbdon]

The number 311 being the same for both Novas and Camaros just doesnt pass the common sense test. It must be a mistake. Especially if you know that the engine code suffixes were normally the same for Camaros and Novas. For example, an MQ code is correct for a 375 396 car for both Camaros and Novas in 68. And those engines were the same. I don't have any proof that L89 Novas were built. I have looked. The book Chevrolet by the numbers does not list any codes for L89 Novas. Also, the option does not show up on the Vehicle price schedule that I have, dated April 1 1969. It would be interesting to look at the same kind of price schedule for Camaro and Chevelle to see if the L89 heads are listed there. By the way, the only spec I can find for the 842 casting shows a 1.72 inch exhaust valve. The 074 casting used on the L88 and on the the ZL1 does use a 1.88 valve

[Chevy454]

Just wanted to let everyone know that we have made a suggestion to the folks at the Pure Stock Drags. Our suggestion is this. Have each racer wanting to run in certified stock sign up in advance, stating that they would agree to a full POST RACE TECH on their car and at that time, prove the legality of any parts in question. After a car's last pass, it would precede directly to the impound/tech area. If a car does not pass this post race tech, then all times, media coverage, etc. associated with this car is moved to the regular class. If some one refuses tech, all times, media coverage, etc is destroyed and the racer is banned from future events. We feel that a post race tech would be much simpler, as the cars could be put back together at home, rather then at the track. It is not the teardown that people dread, its the thought of getting the car back together in a timely manner, plus, getting everything set just right to run the times the car is capable of running. A post race tech would allow cars to be dialed in before they reach the track. This would make for more accurate bench mark times. Also, a post race tech would allow the officials and the media as much time as needed to go over the cars. Tom

[Edited by sYc (10-27-2000 at 05:48 PM).]

[COPO]

Great suggestion!

[Ray Morrison]

Stan,
I do not have any casting numbers, but looked at production numbers on the 67 L-88 Corvette, and find both the L-88 & L-89 options with production beginning in February, 1967. According to this information, 20 L-88's & 16 L-89's were built with these options? I know this doesn't fully answer your question, but this might be of help?

Concerning the exhaust valve size on the 842 aluminium heads, my reference lists them with 1.84 exhaust, also? These are Closed Chamber Aluminum Heads with 106.8 CC's. While looking for information on the 842 heads, I did come across another aluminum head casting number with no application, I did not know existed, that being 838. Is this the L-89 head? Does anyone have the specs. on these?

[Rowdy Rat]

Tom,

That seems to be the best solution to the teardown issue. I hope that Dan and Bob see it that way as well.

bbdon,

The 3904392 (1967) and 3919842 (1968-69) closed chamber aluminum heads did indeed use a 1.84 inch diameter exhaust valve and were the only big block Chevrolet heads ever to use this valve size. I don't know why Colvin chose to use 1.72 in his book, but it isn't correct. The 3946074 head used on the ZL-1 and second design L-88 engines in 1969 were the first to use the 1.88 exhaust valve.

There may have been an even earlier aluminum head used VERY early in the 1967 model year, casting number 3904387, but I have yet to gather any details on this head. Anyone have any information on this particular casting?

Regards,

Stan