Cali Smog Engine Rebuild

[srfinatsunset]

I was wonder if anyone has bored and stroked a 454 and had it passed the California Smog Sniff Test.

I have to rebuild my engine out of my 1980 C3500. We believe it’s a cracked head casket.

Since we are pulling the engine and taking the heads off I might as well do the bottom end since I am right there. I would like to put a Mild to RV Cam in. Possibly make it a roller cam and roller lifters. I just don’t know if it would pass the sniff test. How far can you go before it fails the sniff test?

 

[HotRodPC]

I have not done so to answer your question, but so long as it's tuned correctly the bore and stroke should not matter much. What's more important than the bore and stroke would be the cam and any valve overlap if any. Valve overlap is a certain inefficiency.

 

[HotRodPC]

If it's the truck in your description, the 1980 1 ton, no Cats required, not a CCC (Computer Command Control) Feedback Carb system, I do believe your specs are quite lenient and as said, so long as it's properly tuned, no engine misses, you should be able to pass farily easily with a new remanned engine with good rings and new valve seals etc. Just be sure to have to have it well broke in before you test so that you know the rings are seated well and you're not burning any oil.

 

[hirschdalechevy]

I built a mild big block for a federal cab. stepside that I had a while back and it passed smog , no problem. My machinist , (who was the ****) told me you have to stay 268ish or under for cam selection.

My set up was .030 over 454, early model 396 closed chamber heads, 268 comp cam, 9 to 1 compression, cali. legal eddie performer intake, cali. legal headers, dual exhaust , hei. dist., q-jet carb.

This set up passed smog and hauled ass, but one kicker is that this square was federal so it had no cats and no smog pump, I always look for 78 and under federal square's in cali. for that reason. All that's required is thermatic air cleaner and pcv valve.

I think this set up would work well even with cats and a smog pump. Remember though your tuning needs to be spot on and you will burn clean for the sniffer.

Just a side note , my girls truck with a small block and a 270 roller cam we cannot get by the sniffer no matter what we have tried, (it's a Nevada truck now), and its a 78 federal as well.

So if you bump the compression up a bit and run an rv cam and some cali legal bolt on's, with good tunning you should be good to go and have more power than stock for sure.

I am a fan of early model, big oval port, closed camber heads for mild big blocks. I myself am not a fan of peanut port heads.

 

[DoubleDingo]

I was wonder if anyone has bored and stroked a 454 and had it passed the California Smog Sniff Test.

I have to rebuild my engine out of my 1980 C3500. We believe it’s a cracked head casket.

Since we are pulling the engine and taking the heads off I might as well do the bottom end since I am right there. I would like to put a Mild to RV Cam in. Possibly make it a roller cam and roller lifters. I just don’t know if it would pass the sniff test. How far can you go before it fails the sniff test?

I doubt the sniffer test will matter much. It's a 3500 so the regulations are way more lenient than if it was a half ton. Build it and get it smogged and run it. You just need to pass the visual. That's where they get you.

 

[DoubleDingo]

Mine is an '81 3/4 ton with all the factory goodies on the engine and I can take it in nearly cold and it will pass just fine. Not needing cats and the other bs is huge help with that. They get you on the registration though because they consider it a commercial vehicle. But the emissions testing is a breeze with the 3/4 and bigger trucks of this era.

 

[srfinatsunset]

The block the has 049 head. They are oval ports. I plan on putting new valves and springs.

The block still has the smog pump and charcoal canister still on and working.

Yes it’s 1ton with no Cats with a dual exhaust with a cross over.

 

[DoubleDingo]

Should be fine.

 

[K5ride]

Being a licensed smog tech in California for over 25 years, I deal with this scenario daily. Bore and stroke will not matter. Increased compression ratio will raise your NOx so be careful if your decking your block or taking anything off your heads. As for cam selection, just check that the one you choose has an CARB (California Air Resource Board) executive order number. These have all been tested to ensure they won't negatively affect emissions. As others have stated, your year and weight class is very lenient.

 

[rt66paul]

A clean running engine(new build) will far surpass what the state allows on older engines. Where people get in trouble is when they flap their gums there, or even tell the inspector that it is a fresh build. Make sure to leave all the original parts on the outside of the engine, have a GM intake and carb. You can get away with a cat not sold here in Ca, if asked, tell them it went bad while you were in Phoenix on work. Carbed engines have a lot of leeway, don't go crazy on cam or compression. They might check numbers on the engine if suspicious or even heads. Go in on a weekend when they are busy.

 

[HotRodPC]

The block the has 049 head. They are oval ports. I plan on putting new valves and springs.

The block still has the smog pump and charcoal canister still on and working.

Yes it’s 1ton with no Cats with a dual exhaust with a cross over.

Keep that AIR pump and the Canister, EGR too, farily certain it has EGR so you'll need all that to pass the visual as well as the Thermostatic factory OEM Air Cleaner with no holes drilled in it or lid flipped. So this means the heat riser off the exhaust manifold too.

 

[Jrgunn5150]

I had a 71 K5 with a 307 that failed, I replaced it with a 350 Goodwrench and Crane Fireball cam recomended by their tech line and pssed with no issues. I would worry more about the cam than the bore and stroke.

 

[DoubleDingo]

I had a 71 K5 with a 307 that failed, I replaced it with a 350 Goodwrench and Crane Fireball cam recomended by their tech line and pssed with no issues. I would worry more about the cam than the bore and stroke.

The visual will fail you quickly if the items @HotRodPC mentioned aren't in place too. It may not have an EGR, mine doesn't, but it has all of the other stuff. The guy opens the hood and see a factory engine with all of the items it needs to pass. I asked him about the vortec heads and intake and he said that doesn't matter. It runs clean and looks like it needs to. I was kind of hoping I had to smog mine this year to see what the improvements have done to the emissions, but I have to wait a year. The guy digs my truck, says they are rare, and the 1/2 tons a next to impossible to pass because the added regulations on them. I even asked him about the exhaust, and he didn't even leave the office, just looked out saw 8 lugs and said you can do whatever you want because it doesn't have a catalytic converter. I chose to leave it 2.5 inch single because it runs really well with that setup. But if I wanted to I could run 4 inch duals or run stacks out the hood.

 

[Jrgunn5150]

The visual will fail you quickly if the items @HotRodPC mentioned aren't in place too. It may not have an EGR, mine doesn't, but it has all of the other stuff. The guy opens the hood and see a factory engine with all of the items it needs to pass. I asked him about the vortec heads and intake and he said that doesn't matter. It runs clean and looks like it needs to. I was kind of hoping I had to smog mine this year to see what the improvements have done to the emissions, but I have to wait a year. The guy digs my truck, says they are rare, and the 1/2 tons a next to impossible to pass because the added regulations on them. I even asked him about the exhaust, and he didn't even leave the office, just looked out saw 8 lugs and said you can do whatever you want because it doesn't have a catalytic converter. I chose to leave it 2.5 inch single because it runs really well with that setup. But if I wanted to I could run 4 inch duals or run stacks out the hood.

I put the stock manifolds and everything back on, it was a straight swap, I made it very easy. Then I said/asked nothing at the station, just let em run it lol.

 

[DoubleDingo]

I put the stock manifolds and everything back on, it was a straight swap, I made it very easy. Then I said/asked nothing at the station, just let em run it lol.

I've been going to this guy for years. A Vietnam Vet and a cool guy. I'm not afraid to ask questions, and have got some good info from him. If I didn't have a rapport with him I'd just keep my trap shut.