In June 1969 the HK Monaro was replaced by the facelifted HT Monaro. The 'GTS 327' became the 'GTS 350' with the replacement of the Chevrolet 327 in3 (5.4 L) V8 by the 300 bhp (224 kW) Chevrolet 350 in3 (5.7 L) V8.
There was also an automatic version of the 'GTS 350' introduced which used a lower power version of the 350 in3 (5.7 L) engine coupled to a 2-speed Powerglide transmission. HT Monaro also marked the phasing out of the 5.0-litre Chevrolet V8 and the introduction of two locally made V8 engines, the 253 in3 (4.2 L) and 308 in3 (5.0 L). Late in the HT model run, a new locally produced 3-speed automatic transmission, the Trimatic, was offered as an option, although it was not available on the 'GTS 350'.
The HT Monaro can be distinguished from the HK by the adoption of plastic grilles (previously metal), a round speedometer instead of "strip" style allowing for bringing the tachometer into the main instrument cluster instead of on the floor console, rubber front suspension bushes instead of the HK's sintered bronze, and larger taillights where the turn indicators also wrapped around the now slightly undercut edges. Bodywork 'go-faster' stripe designs (delete options) varied for each series; HK stripes were offset to the driver's side of the bonnet (hood) and bootlid (trunk), the HT had two broad stripes down the centre of the car. HT also had twin air scoops / vents incorporated into their bonnet, which served no real purpose in delivering air into the engine bay.
The HT Monaro GTS350 was successful in Series Production racing. The Holden Dealer Team was formed in 1969 by long time Ford Works Team boss Harry Firth with the team using the GTS350 in competition. The HDT entered three Monaros in the 1969 Hardie-Ferodo 500 the lead car driven by Colin Bond and Tony Roberts winning from 1968 winners Bruce McPhee and Barry Mulholland who had switched to driving a Ford XW Falcon GTHO. Coming home third in the Dealer Team's 3rd Monaro was Des West and Bathurst rookie Peter Brock.
In January 1970, Bond and Roberts would win the Rothmans 12 Hour Series Production race at Surfers Paradise driving their HDT Holden Monaro.