TBI intake restriction?

New member here with a '92 Roadmaster 350 TBI.
I'm familiar with TBI truck engines as I've had a '91 Chevy 1-ton, 350 TBI for 10 years.
However, this car has a different TBI intake setup.
On trucks you have the restrictive "collar" between the TBI unit and the air cleaner housing. This collar shrouds the injectors and reduces flow in the engine. I installed the Hypertech "salad bowl" on my truck that allows a smoother airflow under the injectors and into the TBI.
On the car, it has the factory air cleaner and ducting that appears to be a pretty good, semi-cold air design.
Inside the airbox though, there is a similar collar that is even a worse design than the trucks have. The air is supposed to flow through four, one inch diameter holes and a slight cutout, then make a 90% turn into the TBI unit.
Is there an aftermarket solution?
Is my only choice to take a saw to the collar and cut big windows into it?
I really like the look of the stock housing and would like to find another to remove the intake tube to make mine a twin snorkel.
I've seen the "DeVille" mod and the "Home Depot" mod and am not really a fan.
Thanks.

If you like the way the stock housing looks, I'd leave it alone. You're not going to gain much from cutting and grinding to get more air into it. It's a wheezy 180hp 5.7 liter V8. They're quiet, smooth, reliable, and can sound nice with an exhaust. That's about it, really.

Welcome to the forum, btw.

Thanks Ray.
I've got Summit longtubes , H-Pipe and Jegs Impala SS exhaust waiting to go on.
I did all the TBI mods to my truck to get more power on the highway but the best mod by far was Hedman Elite longtubes, Hooker H-pipe and duals. Everyone on the truck boards said the factory Y-pipe was the biggest power robber and boy were they right!
When I look at this car it doesn't even have a Y-pipe, it has a T-pipe. The exhaust pulses don't merge, they collide! What a restrictive system.
I can't wait to get my new exhaust on and see the difference. I picked up a used GMPP Vortec to TBI manifold so I'm looking for a good deal on some Vortec heads.
I put a Lunati Voodoo 250/256 cam in my truck and it makes good torque, maybe I'll go with the same one or a step hotter in this car.

My car had exhaust done when I bought it. It was pretty nice. Hedman shorties and 2.5" stainless pipe into a single exit (kinda lazy, but I guess it worked). It sounded great.

AFAIK, there aren't any TBI intakes other than the Caddy hat or the chrome hat sold for trucks you sometimes see on fleabay.

If you need a little more air, there are different size TBIs. Stock is a 42mm. I have a 46mm that required me to open up the manifold a little to match, so that I did not trip the airflow. If you get a 46mm, make sure it has the correct fittings for throttle, trans kickdown, and cruise control on the throttle arm. You can also get a set of 9C1 injectors and put an extra gasket under the injector tower to open up the air path. If you put the extra gasket under the injector tower, you have to make longer screws, and it will not fit under the Caddy hat without removing the internal ducting. If you want to be able to measure your fuel pressure, the 91 and 92 Caddy FW with LO3/5s in them have a Schrader valve port on the pressure line, and are an exact fit for the B body. The 93 FW also has a Schrader valve on its pressure line although it is in a different place, and the lines are a little different, but it will bolt up to a B body as well.

The LT1 cam will bolt in to the LO5. You should have a chip burned for the different specs. The LT1 cam tends to come on at about 3K rpm, but makes decent power from idle as well.

Just about any filter holder/adapter for a 4 bbl carb will fit on the TBI, but you might have some height issues with the injector tower. You could rig something to make it a cold air intake. The 93 FW might be a good starting place. It is not really pretty, but it can be adapted to a snout or two, and chrome plated. It would produce an old school look. You could just repaint it black for a more "stock" appearance.

Thanks Fred.
I've seen the 46mm throttle bodies with the "Ultimate TBI mods" and adjustable fuel pressure regulators. Seems like a no-brainer. TBI chips offers a fuel pump, chip and AFPR combo but I would wait until I swapped cams and maybe Vortec heads.
I really like the GM TBI because it is so basic and easy to work on. Not much to go wrong, IAC valve, TPS or a dirty injector. You don't have to be an computer scientist to troubleshoot it.

dwightlightning wrote:

Thanks Fred.

I really like the GM TBI because it is so basic and easy to work on. Not much to go wrong, IAC valve, TPS or a dirty injector. You don't have to be an computer scientist to troubleshoot it.

pretty much same thing with any efi motor,. just maybe a few more injectors,.