So the plans I have for the car include a higher stall for my built 700r4 and of course 3.73's, but are these mods smog legal? How's the MPG with a higher stall?

 

How would tranny or axle mods effect an engine's smog output, to start with?

Other than a resulting different RPM at a given MPH, I don't see how it could affect smog. And since the tests (at least...here in Texas) are RPM based & not MPH based, I don't see any problems.

 

[quote=Stephen;4625437]How would tranny or axle mods effect an engine's smog output, to start with?

You'd be surprised at what C.A.R.B does not allow in our cars. I do live in California, after all.

 

cali is a train wreck when it comes to emissions...of course you can always find a freind to do it for you but...my dad has a high stall on his 98 t/a but idk about gas milage..

 

You will be fine. There is no way that would effect emissions bro. Stall away!

 

[QUOTE=camaromike222;4625645]But like I asked.....How would it effect the output? How could they possibly even know those things had been touched? I don't see how, without running VINs, check GM build RPOs on that specific VIN & crosschecking, after actually checking those things which would require a lot more than a smog check could reveal.

That is my point....HOW WOULD THEY EVEN KNOW?

 

Same for 3.73's? I had them before, but opted for MPG while I put together the LT1 in my garage.

 

youll be fine. remember a higher stall doesnt mean you need to hit that RPM to move. so when they do the test (its a lighter load then driving) the rpms will be fine. even then it wont effect smog in any way. you saw how my car drove with a 2600 stall, its more noticeable under load/ going up hills at at WOT when it flashes at 3k

 

as for gas mileage, after you swapped in my 342's i went from mixed 16-18mpg to over 25mpg. stalls keep you in the power band= better fuel. dont forget to get a lock up to keep the cruising speed rpm tolerable. also keep in mind those meaty tires you have waiting are a bit taller so that will also bring down your rpms

 

Once again you are lacking knowledge in a topic. The test in California is mph based as it is done on a dyno at 15 and 25 mph, hence, a change in torque converter and rear gearing could conceivably alter sniffer test results.
And while the practical application of the law leaves things like that alone, if they wanted to apply the letter of the law, I'm sure some bureaucrat at the CARB could construe things that are written to make mods like that illegal. You are technically changing the car from the configuration that earned its federal emissions compliance which is a far more in depth series of tests than is reproduced by any of the annual or bi annual tests at the state level.

But to answer the O.P. question, no, the practical application of the law does not concern itself with torque converters or rear end gears.

 

You REALLY need to learn some tact

I also posted with QUESTION MARKS, as to how it could possibly affect the results.

 

It has not been a problem with the cars we have taken to get smogged.

 

Thanks for all the info guys. It is inevitable that I swap my LT1 into my car along with the gears and stall. I have just always been curious. I also needed to know so I can take it to the "right" smog guy. I plan on going with an Lloyd Eliot cam, full exhaust, ported heads and all the bolt on goodies for the engine.

 

I do remember getting 17-19 hwy when I installed the 3.73's. As for the tires, they are the BFG KD 315/35/17. The ones I have now are 275/40/17. If anything the meats will be slightly shorter.

 

back then i had 323's(still do) as well a 3200 converter and a shift kit on my 700r4..(Which is now on my 70 caprice)...passed smog fine...sooooo i guess ur good!!!

 

Swapping an LT1 into your car WILL require going to the referee and having it recertified. Even though its more work, I suggest putting a stock LT1 in first and then going to the referee. The smog referee will go over the engine with a fine-toothed comb and ANYTHING that is out of place will trigger a red flag. Don just took an El Camino with a TPI conversion to a ref for a recertify from carb to TPI, and the ref failed it because it had a 3-wire heated O2 sensor instead of a 1-wire one. Once you pass the recertify process, then you're free to put any CARB legal mods on it you want.