Ok so the more I learn about my 1966 Ninety Eighty LS the more I am puzzled. Everything I read mentions that the car ONLY came with a 425ci BBO with a 4 barrel. My car has a 425ci BBO with a 2 barrel.

I vaguely remember the guy mentioning that he switched it to a 2 barrel (NO IDEA WHY). So obviously I would like to switch it back to a 4bbl but that would mean getting an intake, carb and air filter housing. The intake and carb are relatively easy other than $$$. Its the air filter housing I'm worried about. Are these things still common enough not to cost me an arm and a leg??

DSCN1164.jpg

DSCN1165.jpg

 

Std was the 365 HP Super Rocket, and optional was the 375 HP Starfire, both 4-bbls. The number stamped on the front of the passenger side head will tell you which one you have.
Guessing he changed it for gas mileage. Truth is, you'd get better gas mileage with a 4-bbl if you stay out of the secondaries.
A 4-bbl air cleaner should not be that hard to find, nor too expensive. Decals for either engine version are available.

 

From the pictures the valve cover breather looks to be 67 vintage.....

 

Can't wait for the spring so I can get in there and clean up that engine bay. Its really buggin me.

 

Another odd feature - it has a throttle dashpot. To my knowledge, they were used only on A/C cars. The engine number on the head will end with an "S" if it is the optional Starfire engine. The intake, etc will still be the same either way. That also could be a low compression export engine but they were also 4bbl. That number would end with an "E".

 

Man did I ever make a huge mistake a couple years ago, I had a 66 425 4bbl intake and carb, sat for years and thought nothing of it and chucked it at a local dump, I know its a sin!!! I coulda just gave it away instead..........

 

How can you sleep at night??? That poor intake and carb!!!!!

 

I did the swap to my car and I had to add an 1 1/2in. to the throttle rod to make it work with a quadrajet off my trans am.

 

At first it was very hard, LOL I know I still can't believe I did that!!!! Can't wait to see that engine bay will look once you're done with it.

 

Doesn't Offy or somebody still make intakes for the 425 and 455? While looking for Tri-Power or something cool for my 394 Sky Rocket (like the 303, 324, and 371, the 394 is from the '50s and apparently counts as a 'First generation rocket', the 425 and 455 from the late '60s and '70s were a different generation, more modern design) I seemed to come across a lot of stuff for the later engines like the 425 and 455, more so than for the 394's for sure. Good luck hunting. I once drove a '66 Olds 98 with the four barrel, its a mean setup and I loved it. Apparently those 425's got decent mileage, too, I think I've heard 18 mpg highway. Can anybody confirm this?

 

Here's a link that might have what you need. Look at the bottom of the page...the stock 4bbl. intakes from '49 to '72 should include one that fits your '66 425.

http://www.oldsmobilecarsandparts.com/catalog9.html

 

I have to say 66 was the first year for the quadrjet as we know them today. The 66 carb was different then any of the later models, had an arm and plunger assy to operate the secondary air flaps on the top of the carb. I remember my dad saying that year was a problem with flooding over even when the cars were new under warranty so some owner might have been fed up with the carb problem and just put the 2 bbl on so he could drive it without any problems.

 

Good point! That is quite plausible, and certainly a valid reason to consider swapping to a 2-bbl.

 

NO NO NO!! There is no valid reason to switch to a smaller carb!!!!

Just got my shiney new carb in the mail today. Should look sweet!!

 

No I wouldn't switch carbs either but I can remember those first Q-jets being a real bear, I actually had 2 of them, sold one to a guy with a 66 Starfire after I rebuilt it, and it worked very well, saw that car at a local car show here this past weekend and he's had that carb on it for well over 5 years now

 

From what I understand, the plugs in the bottom leaked and caused the problems. And a few fires! Epoxying the plugs was the cure. I'm sure there was a Service Bulletin about that too.

I dunno, but I think a fire is good reason to consider the swap. An there was the misconception that that a 2-bbl would save on gas. Yes, there were those concerned bout gas mileage even back then.

 

That epoxy trick was a service bulliten in the 70's that I know of but for a real mechanic we first flattened the plugs with the aluminum seals before applying the epoxy, the company standard carb kits came with a foam insert to put under those plugs to seal it but really the epoxy worked very well. The plug thing was in the bottom of the float bowl so if you didn't seal them a few day sitting would turn into a long crank time to start because you had to fill the bowl before it would start

 

actually I remember something about JB Weld as the product to use or another one was 3M they were the only ones listed