1999corvettels1

First off this isn't about a Corvette but old Chevy engines, I don't have a C3, I have a 1965 C10 short bed pickup with a 1968 pickup 396 and TH400.

The exhaust just stinks, maybe I'm used to modern fuel injected and cats.

Just wondering if others with these era of engines have any that don't make their clothes stink, or garage?

I put this engine and transmission in the 1965 C10 in 2004, from a 1974 running pickup I bought for the engine (supposed to be a 454) and rebuilt TH400.

The engine decodes to a 310 HP 396 from a 1968 pickup.

I'm wanting overdrive but the idea of a LS engine, even just a 4.8 or 5.3 with overdrive attached might be the better way to go instead of buying a rebuilt 700-R4 to put behind the smelly 396.

Curios what others think.

Tiger Joe

Short answer is no


a carb'd engine is never going to run as clean as fuel injection, so it will always have some sort of stink, however a properly running engine shouldn't stink

crawfish333

Mine kind of stinks when it is first cranked up. After it is warmed up, no smell. I assume that is just the choke causing it to run a little rich.

doorgunner

A 700R4 is a great transmission if set up correctly.......and a boat anchor if set up wrong. There is a year of manufacture (I forget) that is "built" better than previous years "late 1989"? There are rebuild kits that make them even better. I had 20,000 miles on my street truck 350 cid 700R4 transmission when I sold it to buy my Vette project.

As for the "stink"....tune the engine properly....take notice of the smell. Add a "cat".....two cats if true dual exhausts are installed.
Cliff's Notes...........


Example: Single exhaust/buy a quality free-flowing cat.

Dual exhaust: Buy two cats equal to the engine C.I. D. Example: 400 cu.in.engine----buy TWO cats, each designed for a 200 cu.in. or larger engine.....install one per exhaust pipe.

You can also install/DIY a HEATED O2 SENSOR in one of the dual exhaust pipes and use an inexpensive digital multimeter to read the output as you fine tune the carb/ adjust the other side of the carb by counting screw turns from closed position (or take the time to install a 2nd cat in other exhaust pipe)`

Result: No more smell/no burning eyes/no stinky clothing or garage..........performance remains basically the same for a street vehicle (performance oriented members will disagree)

YES....I HATE CATS.......but the improvements are worth the time to modify the exhaust system.

Also.....if you like the deep sound of a Corvette (NOT a noisy resonating sound) you may NOT need mufflers with a dual cat set up.

crawfish333

You kind of lost me, please help me out. Why would you need to put cats on a car that was not orginally equiped with them? I have never heard of anyone doing that, but I am not an expert.

oldgto

I agree with Tiger.... it shouldn`t stink like you describe it. And I`d love to see pics of your truck! We`re building a 65 long fleetside C10 with a 1966 283 engine.

Crimson Thunder

It's mostly caused by the way todays gas is formulated. There was an article in Hemmings a couple of years ago about it.

Haggisbash

I would expect any carb equipped non cat engine to smell a little more than a similar engine equipped with a cat and or fuel injection. If it is eye waveringly bad though I would suspect the state of tune needed checking.
In answer Crawfishes question, fitting cats to the non cat car will provide a decrease in emissions with the side benefit that they can act as resonators to improve the exhaust note, I agree with Doorgunner modern cats shouldn't affect the performance of the average street engine.
I have had to fit resonators to my '70 recently to get it past testing because it was too loud after I upped the compression and changed the cam. The exhaust note is deeper and the droning in the 2000 - 2500 rpm range is gone.

flyeri

If the exhaust has a gas smell you need to tune it. You still may smell that somewhat when the choke is on. After it is tuned correctly you will still have the exhaust smell, sort of like a lawn mower. The cats will help reduce the exhaust smell by further cleaning the exhaust. The practice is not uncommon.

doorgunner

I'm not an expert, either....I'm learning as I go along. (Have you ever been behind/on the side of a vehicle in stop 'n go traffic that had a terrible smelling exhaust odor?) You don't need to do so, but a stinking garage/foul smelling clothing/"burning" watering eyes/etc. would be good reasons to consider a cat or cats.

I will fit my project with dual cats and will document/take pics of the modification.

scrappy76

I am not sure how much stink you are talking, but it shouldn't smell as bad as you are describing. Though older cars without cats and carb'd will have a different smell.

I have a 100 mile round trip to and from work everyday. I can always tell when there is an older car ( carb'd, no cats ), in front of me. Honestly, I am old school and i still enjoy that different smell.

derekderek

May well be the 454 carb on that 396. Jetted too rich. Jets are cheaper than exhaust upgrades, but a boat guy made an adaptor to stick a wide band heated O2 sensor up the tailpipe to get the A/F ratio set up correctly.

crawfish333

I guess I just remember the old days when the first thing some people did when they bought a new car was remove the cats. I had a 1 year old 81 Olds Cutlass that had low mileage on it but was out of warranty. The engine went out becsue the cats were defective. My wife was driving the car at night and when the light came on she did not know what to do so she tried to drive on. I had to buy a GM replacement engine. Back then Catalytic converters were not very popular.

1999corvettels1

I bought a 850 cfm Q Jet, the ones Edelbrock made at one time, only run a few times according to the guy I bought it from, it looked new, and it was in the original box with owner's manual.

According to the Q Jet guy Cliff Ruggles, these #1910 Q Jet carbs came set up with a extremely rich idle for a big cam, so I need to tear into it and put in smaller idle tubes and smaller jets and open up lower IAB.

When I got the engine swapped into the '65, the Edelbrock (Carter AFB style) 750 that came with the 1974 pickup would not run very good, so I put on my CarterAFB 600 left from my SBC I pulled out of the '65.

The exhaust stunk with that carb also, maybe not as bad.

I will do what Cliff Ruggles suggested, and see if that helps before moving on to installing cats.

The idea of cats I really like, I was wondering after someone swaps a LS family into a classic with no cats, would it stink?

Sounds like a LS with no cats would stink.

Strokemyaxe

I think the OP is misfiring on info. Likely you are just smelling cats vs no cats or rich vs stoich. All engines that run gas will smell relatively identical given proper/similar tuning.