I thought only the last year or two had the 'big' turbo (and EFI). IIRC the draw through setup they had was a smaller turbo.
86 & 87 had a larger turbo but it was not that big.
Yes the older Regals had a draw through set-up w/a Quadrajet 4 bbl carb,& yes,the turbo was smaller.
MBHD