Turbo 383 in a A-body Barracuda

CUUDAK said

Also,
1" 7/8's Weld-up header kit, Header flanges(did not come with the header kit), 3" v-band clamps, T6 1/2" flange, Carb bonnet.

Now I need to find a local muffler shop around Hempstead for the 4" downpipe.... The S480 has a 5" exhaust housing. The turbo comes with the 5" starter pipe and a 5" to 4" reducer. Hope reducing from 5" to a 4" downpipe won't cause issues????

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I'm not a turbo genius, But I do know that turbo's hate restriction in the exhaust. The standard exhaust that most people run for NA BB's is dual 3" which gives about 14.14 sq" of flow area. To go to a single 4" you would be cutting that down to 12.56 sq" of area. If you went to the 5" you would have 19.63 sq". There is a reason the turbo has a 5" housing. Turbos pump a lot more air than NA engines. Just some food for thought.