2-barrel carb & intake to 4.1 intake swap note...

[Freddie's Buick]

If one has done this swap, use the 4.1's intake manifold pan gasket. I did'nt. As a result I've lost out on a little more HP, and I can't get the EGR system to function properly.

The reason for using the 4.1's gasket is that the 3.8's exhaust crossover heat passages on the cylinder heads are larger to promote 1975 and up emission standards. (EGR system). The 3.8's intake pan gasket is also set up with the larger openings. Race applications plug the openings up completely for more performance.

The 4.1's intake pan gasket has a reduced smaller 5/8 opening compared to the 3.8's excessively huge ports. For street car drivability it is recommended to have the ports opened, but the 4.1's pan gasket's openings gives one the best of both worlds by reducing the size of the opening for more HP, and maintaining the emissions control functions.

I will now have to rip it apart once again to install the 4.1 pan gasket once I can get a hold of one......

 

[RCI2990]

hey thanks for the heads up.looks like another trip to advanced auto for me.i go there so much they know me by name and my car.

 

[Freddie's Buick]

Hey RC12990,

Here are a couple more interesting tidbits. The 1981 Pace car, (which was a sooped up 4.1 liter), was in large part handled by Jim Baker and his crew. Another well known figure associated with this project was Jim Ruggles.

Ruggles had this to say about the 4.1 4-barrel intake, 'The stock
4-barrel intake is a damn good manifold'. In fact, by swapping this manifold onto the 3.8, Ruggles read an increased horsepower rating of 138 on his dyno.

It has been erroneously noted that the stock 3.8 horsepower rating is 110. Truth is, that this is the 1975 rating of which came with a one time 2-barrel intake and a 298 cfm carburetor. From '76 on a differant intake was used with a 205 cfm carburetor. This dropped the horse power rating to 105 and this application continued throughout the 1980's. So as one can gather, the stock 3.8 2-barrel application is geared for economy and not speed. It is truely a slug. Most 4 bangers today have more horsepower then the stock 3.8 V-6 non-aspirated engine.

But thats o.k., it aint too hard to bring it up to par with the faster cars. Your trips to the boneyard are cheap and easy horsepower. With time one can wake up this turtle and turn it into lion. Just look at what the turbos can do......