What Size 4bbl for 81 buick 3.8
- Thread starter 81regalta
- Start date
- Status
Don't need anything over 300cfm for a two barrel. If you search junkyards for big 80s Buick Electras, LeSabres, Park Avenues, and the 4 door oldsmobiles and pontiacs those could have a 4.1 Buick V6 (just a Buick 3.8 bored .030 over and with the bottom end of the turbo 3.8) and all of the 4.1's came from the factory with a quadrajet and a four barrel intake. Bolts right on. Get the computer too if it has one and your car has one. Never get a quadrajet with any kind of blue or black electrical plugs and skip the computer stuff because it wont run worth a damn without the computer controlling it.
I decompressed a bit with some schnapps while deciphering the above post re:4.1L engines and the like. (Surfing here is what I do when my bad rib and such keep me awake.)
My answer presupposes you do not need emissions for the car and your purposes.
Simple answer to your question is a 500 cfm edelbrock would do nicely. Get a pair of tube headers since you won't need the sensor in the cast iron ones anymore.
Eliminate the computer entirely, pulling the smog pump off while you're at it.
Cat converter can be replaced by what they call a "test pipe" or "dump tube" in the grand national circles.
Also, do yourself a favor while you have the intake off and fluids partially drained: pull off the front cover and switch the factory nylon teeth timing set to a steel geared one. The extra $100 and hour or two of your time is worth it.
You're going to want to alter the timing when tuning your new carb setup anyways.
Edelbrock carbs have a lot of issues, so many people who have shitty running cars have the Edelbrock carbin common. Get the Street Demon 625 cfm or Holley 390 cfm. Almost any aftermarket carb will need jetted down to run right with that 100 HP wonder. Do you have dual exhaust? Go with 2" dual exhaust, not sure how bad Buick's exhaust is but Olds cross over set up and manifolds are awful. My Olds 260 factory other than dual exhaust isn't that terrible.
I agree some people with cars have issues with edelbrock carbs, part of that goes with the sheer number of them out there, number of second hand used purchased, etc.
But there is NO way a Demon 625 is going to run worth anything in on a n/a 231. It's just too big, too much carb.
The 500 cfm is at the upper limit and can be made to work ok, also affording room to grow into over time with cam, heads, or later rebuild.
Holley 390 I would agree to be a good choice, however, it is easier to out grow over time. I'm of the buy once mentality and reuse arls much as possible through advanced levels of builds.
The Street Demon could be made to work, basically a Thermoquad. The 800 cfm version of that carb will work fine on a 318. That 4.1 factory Qjet was 750 cfm, if not 800 cfm, probably with the secondary throttle blades and air door limited for the small cubes.
Thanks for the information, what all would be involved when removing the smog pump and emissions? And where can I find a steel geared timing set?
yank it off remove air hoses,plug with vac caps where needed and remove the belt or if you have a one belt setup you'll need a smaller belt,go to orileys for the timing set you can get a cloytes setup for like 20ish bucks,ive never run into issues using them and personally hate the sound of a gear drive
sorry double post but forgot the emissions part,as stated in the other thread pretty much yank the computer,get rid of the air system plug the holes with npt pipe plugs though REMEMBER to get the little flutes in the air ports out,spray with a bit of pb blaster than tap a flat head into the port,dont go nuts but when you feel a bit of resistance twist it alittle and yank it out.get rid of the cat and strait pipe it back to the muffler,obtain vac advance distributor and carb not much over 450 cfm to optimal performance...too big a carb and your gonna have issues.pretty much what everyone else has told you but i didnt see mention of the air port flutes so remember those they do screw up exhaust flow a bit.atleast the 3.8 is semi bullet proof,pretty decent engine to do some learning on
- Status
