C&L Throttle Body Upper Intake Plenum (02-04 GT)

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i was reading on the american muscle "when should you upgrade your throttle body" that with mild bolt ons like a CAI and exhaust its not good to exceed a 70mm throttle body size but i hear a lot of people saying in the comments that they paired this upper plenum with a 75mm throttle body, i bought a 70mm, is a 70mm good with this plenum with mild bolt ons or could it have handled a 75mm throttle body with mild bolt ons (CAI and exhaust) with no issues? did i make the right decision using a 70mm throttle body? will it create back pressure at the interface and if it does is that back pressure a good thing if eddy swirls and turbulence are created? 1 answer

• The C&L Upper Intake Plenum can work well with a 70mm or 75mm throttle body without issue. The issue that decides what size throttle body to utilize comes down to the work done to your vehicle, as a more heavily modified vehicle will draw enough air to utilize a 75mm, however a lightly modified vehicle may see some benefit at higher RPM, it will loose some low end power, and throttle response if paired with a 70mm Throttle body. We typically do not recommend the 75mm for cars with anything less than CAI, headers, and cams, as performance gains tend to be negligible going from a 70mm to a 75mm on these setups, and throttle response will tend to suffer. On cars with mods as described, airflow is significant enough that we see good gains going with the larger throttle body.

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Work with Vic Jr? Would the C&L plenum work with the Victor Jr intake and if so, would it be better than the Edlebrock plenum that is suggested with the intake? By sight alone , I see it doesn't match, so is there an adapter to make it work or is it just not possible? 3 answers

• It will work with victor Jr intake,, you just have to get the adapter plate for the plenum to bolt onto the intake. I have a 02 4.6 that I'm doing the victor Jr intake on. MMR is the only place I've found that offers the adapter plate

• After some research I did before I bought this plenum, I found out this product was designed and optimized to work with the PI intake manifold and a 75mm throttle body. The Vic Jr would definitely respond better to edlebrock's plenum and the 90mm throttle body they suggest. Plus their could be hood clearance issues. If you are stepping up to the vic jr manifold I would go with what AM/Edlebrock suggests.

• It will not work with a Victor Jr intake as the base is designed to bolt to a stock intake. I am not aware of a Victor Jr intake available for the 4.6L V8. There are aftermarket intakes that will probably work with this Plenum that are available.

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