Could it Pass??

[avsfan992004]

I have an 83 C-10 and it has the stock 305 motor in it. I recently came across a 350 motor with a high compression ratio. (I think it's 10:1 or 10.5:1, but I can't remember completely.) According to my buddy who has the engine, it came out of a 69 Corvette. My question is if I was to do the swap could I get the motor to pass smog out here in California?

[piecesparts]

Doesn't the smog numbers follow the year of engine that it is, in California? I thought it was like that the last time I was staying your great state. If you put a 69 engine in a truck of a later vintage, then the readings should be the same as the vin number that it came from. However the Smog Nazi's are always changing the rules.

[chevybuldr]

It would pass as being a 305 since they both look the same externally. As for the passing the sniffer that might be a different story. Each area is different in fine place we call the bay area. Go to your favorite smog guy and ask him what is needed on a visual underhood.

[AceX]

Just off of the very limited information you've provided, I'm inclined to say, No, it won't pass without some help.

You'll need to make sure that the egnine is clean, and the cat(s) are VERY hot when you go to do the test. this could mean a good bit of driving around first. Somewhere in the range of 45 minutes to an hour. I'm not 100% sure, but switching to updated cat(s) might be a good idea. Newer cats are more efficient than the original one, but they are meant to run much hotter.

I'd look at getting a set of cats from a mid 90's 5.7L truck, and give the engine the Seafoam treatment a while befre the test. At least a full tank.

There are other tricks like mixing alcohol with the fuel, timing, and bribing the official, but I don't suggest ANY of the above...

Best bet is to update the cats, and makes sure the the entire intake, exhaust, and fuel system is clean as can be.

[Malo83]

Just smogged my 83 Silverado with no problems , If your 83 is a Cali truck you'll have problems with the swap,our trucks run a Computer to control all the functions along with the electronic Qjet and you would need to reprogram the chip and you have to pass the visual

[avsfan992004]

Originally Posted by Malo83

Just smogged my 83 Silverado with no problems , If your 83 is a Cali truck you'll have problems with the swap,our trucks run a Computer to control all the functions along with the electronic Qjet and you would need to reprogram the chip and you have to pass the visual

How do I reprogram the chip??

[Malo83]

Get in touch with these guys
http://hypertech.com/

[smogdave]

In the State of California, You can upgrade an engine if it was available in that model and year. You are not allowed to downgrade or replace with an older engine. I have a 1976 c10 and installed a 1988 454 TBI. I had to smog as a 1988 with the California Smog Referee station. I have done smogs since 1986 and they are pretty strict here in California. My alternate plan was to buy a 1975 truck and reregister as a 1975. I had all new exhaust put in with 3" pipe (factory for that engine) along with a new 1988 OEM/aftermarket cat. It runs clean as a whistle and all of the computer control components function as designed for a 1988. The transmission is a THM400 and the truck kicks butt! There is on major problem that I am having, TRACTION! It's all good though! Good luck!