[richtazz]

If that is a typo, and you meant GTP not GTO, then they should be the same (or similar enough to be easily modified). GM has never produced a GTO and Regal based on the same body style platform, so regardless of whether you're talking about vintage muscle cars or more current models, they are not interchangeable, nor did they ever use the same motors. The 98 Regal GS in your profile is based on the GM FWD W-body platform and shares many parts with the Grand Prix GTP. The newer 04-up GTO's are based on the Australian built Holden chassis, and are RWD with a V-8. Back in the old days, the Regal name didn't debut until 73, and was based on the GM mid-size A-Body (shared with the Chevelle/Malibu, Olds Cutlass and Pontiac Grand AM...yes there was a Grand Am in the 70's). The GTO in 73-74 (what an insult to the name) was based on the Nova/Apollo platform. The older GTO's (72-back) were based on the same chassis as the Chevelle, Skylark (GS), and Olds Cutlass/F85 and didn't share V-8 engines like they do now. Save for a few exceptions, each GM division had it's own V-8engines.