I have a 1999 Bonneville SLE and I want to put in the series III 3800 engine in. The stock motor has a 3.8" pulley on it and i want to put a smaller pulley on it like for example 2.8". The smallest they goes is 2.4" but i would have to machine the snout of the supercharger to get it to work. If i was to put on the 2.8" pulley would the motor be able to take it or not.

Not without a LOT of work.

You will need a cam, CNC heads, headers, and intercooler. Not to mention the transmission work needed to handle that power.

well i am getting the trans fully built anyways. but thanks for the feed back was not sure what need to be done or not.

When you've put in all the supporting MOD'* contact Billboost37

He has a turned down snoot on a series II

Unlike with turbo'* the supercharged motors are not necessarily all about adding more boost or positive pressure.

An S3 motor would be a nice choice as it has the more efficient charger (same amount, colder air). Guys running pullies smaller than 2.8 would be cammed, have heads, headers, larger injectors, stiffer motor mounts, intercooler and many other supporting mods in the engine.

From a trans perspective you'll not only need a rebuild but an upgraded rebuild with stronger single chain instead of two seperate, HD output, upgraded clutches, valvebody etc etc. And even then, there'* no guarantees that once you start getting up in power you won't murder it.

Now..adding a cooler charge into the cylinder and upping the timing a little can have a great impact on power levels. A person with a tuner and experience can do amazing things to even a stock motor. Then when mods are added it has a much more profound effect.

well i am sending my old trans and they are going to rebuild it into a racing trans with all up grads to it. example Thrasher Shift Kit, Brand new stock dual drive chain is installed, Heavy duty Thrasher Clutch Packs are installed in 1st, 2nd and 3rd gears, All new seals and bushings are installed as the transmission is re-assembled, Any damaged or worn parts are replaced with new, and from there i can up grade it with/ * C-Ya Racing Limited Slip Differential
* C-Ya Racing High Torque Input Shaft
* C-Ya Racing Single Drive Chain (60% stronger than stock)
* C-Ya Racing Torque Converter & Flex Plate
* C-Ya Racing 2.93, 3.29 or 3.69 Gears for single drive chain (PCM reprogramming may be required)
Any of these can be installed in the trans with extra cost, But since i have been looking around and gathering info about the motor ans such. i am going to build the motor with all forged internals and go from there. But thanks for the feed back.

Sounds like you have done your homework and not jumping in blindly. OK, once the transmission is set you will need a good set of heads and a good cam. With the right heads you can install higher lift rockers as well to increase flow. Larger valves will help. Real good headers and 3" down pipe. ported and polished intake and a good intercooler. 3" core if you can. You will need large injectors and a large MAF. I don't think I missed anything. Other then tires that can hang on to the road, because you are going to boil nearly anything you put on that car.

Honestly the price is a little high for what I'd call a basic rebuild. Having gone through a few transmission parts personally and dealing with a few guys in the performance building arena I'm not sure I'd be comfortable with the parts they are not planning on changing for the $1949. Things like soleniods, you want them new.
Performance 4T65E/ HD Race Transmission: 3800 Performance

Here'* the Thrasher home page. Customer Service - Meet our Staff - Pontiac Grand Prix GTP, Chevy Monte Carlo / Impala SS, Buick Regal GS - Thrasher Engineered Performance It explains how Thrasher was bought out by Autotrix a while back. Which is why very few things from Thrasher are new or innovative. Their intercooler isn't available in a Gen V M90 configuration according to the site.

Here'* another site for a transmission in your reasonable area. Triple Edge Performance - Home Page The guy running the show is Dave Norris, available via phone, many forums etc. For the price of $1500, the transmission has everything of the Thrasher, plus all new soleniods and valve body upgrades. Guys wanting to build a serious transmission will talk to Dave and read up on his site as there is tons of information there.

When my trans was first rebuilt it was updated from a 97 valve body etc to a 2003 which is the latest version. From one guy that spent his share of money learning these things to another, please never stop asking and researching options. Last thing I want to see is someone have their transmission out as many times as mine was this past summer.

put just a 3.4 pulley or 3.2 the most you can go without do other mods

NO!! Sorry buddy. Nothing smaller then a 3.5" on a gen3 supercharger with out mods. I barely run a 3.2" with my setup. You also need to scan for KR when that small.