Best Brand for FK5 match

I have a 1970 Dart on which the owner wants me to paint the engine compartment while his 440 is out getting built. The dilemna is that he has already had the exterior of the car painted and is not happy with the paint color - it is a little bit "off" from what you can see under the hood and in the trunk. It's too brown. The body shop actually painted it twice because the first time it was way too brown. They used PPG Shopline and gave him the leftover paint when they finished the car.

He really want the engine compartment to be the right color instead of matching the body because he actually plans on repaint the entire car some time down the road anyways - he's not happy with the body work on one of the quarters.

I know from experience that colors can vary greatly from one manufacturer to another. I had some FK5 made in Omni a while back and it was WAY off from what it should have been. I only want to do this once and need to get it mixed right the first time(since it is really not a high enough paying job to do twice). Anybody with experience painting FK5 that looked good, please let me know what brand you used.