1975 engine and exhaust options

Hi, got a question about my recently acquired 1975 LeSabre.

Mine has the 455/4 option. The strange thing is that it has factory fitted dual exhausts. Those weren't available in 1975 officially according to Buick, the brochures and the interwebs.
In 1974 that option was available.
1975 had a catalytic converter. Mine does not.

It was bought new by a gentleman in Canada. It was built in Fairfax KS.

Is it possible the original owner asked the dealer to fit the car with the exhaust system of the 1974 LeSabre? (1974 had dualexhaust options for 350/2, 350/4, 455/2 and 455/4 and stage1 455).

Also I read in the 1974 brochure that the 455 came in 3 flavours (first two with option for dual exhaust): 2 barrel 175/190hp, 4 barrel 205/230hp and 4 barrel stage 1 with 'electronic high-energie ignition' 245hp.

Is the 'electronic high-energie ignition' the only difference in the Stage 1 Vs normal 4 bbl?

And if so, given the fact that for 1975 that 'electronic high-energie ignition' was standardised and my car having dual exhaust, would that mean my car has 245 hp? Or just 230?

Hope someone can help me with this mystery.

 

The 'Stage 1' designation on the big cars meant you got heads with bigger valves. So you could flow a bit more air, thus the 245 hp. The HEI really doesn't have much to do with the extra hp, but I do feel HEI is superior to points. In 1975 the head design was significantly changed for emissions reasons. So no more Stage 1 option.

As far as the exhaust goes, very likely someone put in the duals and got rid of the cats. It's almost a 50 year old car so a lot can happen in that time. Unless you have some documentation that says the duals were from the factory?

 

I agree with Luxus; many people had driveability issues from the emissions equipment. The restricted exhaust hurt power. Factory carbs were lean, too, but fixing that could kill the converter. Clogged converters would cause overheating (as on my parents’ new ‘76 Electra). Although it was violation of federal law, gutting or removing converters was very common and the smartest way to go was a factory style system from an earlier model.
Patrick

 

Okay. Thnx! The seller showed me on Skype ,when I inquired about the car, some documentation that the dual exhausts where installed before the car was delivered to the original owner so it really was factory or dealer fitted. Guess maybe the dealer offered it and ordered 74 exhaust system for it and threw out the converter.

I didn't knew about the difference in heads in 1974. Thought that was with the pre 1973 cars only. Thanks for that info.

So now assuming I have a normal 1975 455/4 which normally would make 205hp is it now safe to say the power went to 230hp because of the dual exhaust (Just as it did in 1974 when you ordered dual exhaust on your 455-4)?

Everything under the hood is still there and bone stock. So all the emissions stuff is there. I don't mind it. It runs great and smooth and I don't 'race' it. Just when somebody asks me "how much power does it make?" I would like to have the correct answer.
And of course I am curious about it myself hahaha.

Also I noticed in the brochure of the 74 that the 455-2 made significant more torque than the 455-4 (although less hp). How come 2 bbl makes more torque?

Again many thanks!

 

I can’t remember if the two barrel had a different camshaft than the four, but that would be the only real explanation (versus Buick just fudging the numbers). As for the heads, they’re the reason your compression and power aren’t spectacular, but the bottom end is solid. A swap to ‘74 and older heads wouldn’t be too difficult and would wake it up some.
As for ‘how much power does it make?’ pick a number; you won’t be far off (and the people who ask likely won’t be impressed in this day of hot little engines making 100+hp/litre). I don’t know how much of the ‘74-‘75 difference was heads, converter, or just ‘we changed the number’. Tell them the displacement and weight and let it sink in that, at one time, US personal coupes were bigger than Suburbans.
Patrick

 

I am curious myself on the a little higher torque with a two barrel thing. Maybe one of the engine experts here will chime in.

My guess is the smaller opening (carburetor) makes the incoming air go a little faster and packs the cylinder a little more. But it's just a guess.

 

1975 455 4bbl had 205 hp

 

True. But that was the power figure with single exhaust and with the catalytic converter. Mine had duals fitted with the catalytic converter deleted.

 

The converter was a Federal mandate, SOMEONE removed the converter, put a crossmember in from a ‘74 full size Buick, and added duals. I did the exact same thing on my 1975 Electra, not hard to do.
Your car did NOT. Come from Buick that way guaranteed.
205 hp was all you got

 

It was delivered in Canada. Maybe that makes a difference. We (the seller and me) believe the dealer who sold it new maybe did the exhaust swap for the guy who bought it. He showed me the order/receipt paperwork for it when I was looking to buy it and it clearly stated the dual exhaust extra on it. So idk. But I sounds possible the buyer wanted it this way and the dealer just doing what the client wants and order a 74 exhaust with the car and swap it out at the dealership. Anyway... I know and always knew what the powerfigure is with the catalytic converter installed. The question of this topic was what kind of power does it have without the CC and with duals added....

 

None from Buick. The seller had a dealer orderform and some papers where it showed. It was from the same dealer that is on the dealer plate on the car.

 

Does it say anywhere under the hood like on the emission label on the radiator top plate or the A/C box that the car was built for export and conforms to Canada emissions?
I honestly don’t remember what Canadian emissions standards were for 1975.
I DO know the old pellet type Catalytic converters we’re very restrictive
I DO know you could buy a “Test pipe” at most any auto parts store for awhile after 1975, heck well into the ‘80s

 

If you can post pics of the drivers side exhaust manifold.
There was something different between the 74 and 75 left manifolds, IIRC it had something to do with the heat riser valve.
I can’t remember right now