7K revs! That must be the original version I gather, as the Gr C version is limited to about 6300? The original car shouldn't wind out much beyond 6000 at the most in top. 5500 is possibly slightly low, but it is still in WIP mode. It's very difficult to match these cars up be historically accurate as they cover production to Gr C regulations, plus there's the other issue of only 1 HQ racing in 73-74 (first with a 308 then a 350). There's other issues with how 'realistic' to make them. The cars weren't matched for lap times & things such as over revving the engine will rapidly stress the motor (eg. Brock had to keep the A9X under 6200 revs down Conrod Straight at Bathurst otherwise the motor was inclined to expire rather quickly). There have been testers who have already pointed out that the cars overheat in only a few laps, but that is how they would actually be if you did that in real life. Trying to get a balance between enjoyment & reality is the hard part. We're also trying to get a balance so that they retain an individual 'feel', but also can match each-other over an endurance race (the Gr C version at least).There may be a 'Muscle Car Masters' version, so a 340 V8 Charger is still a possibility!