Coupla things to consider while motor is apart.
Compression ratio. Might want to dial the CR around 9.5 - 9.75:1 to run motor on pump gas with iron heads. You can go 1/2 to 1 point higher with aluminum heads. My TFS' dialed in at 9.65:1, a little conservative, but runs fine on pump gas.
Cam. That is a wimpy cam for a 351 Cobra motor. No wonder it idles like a stocker. (I put a cam like that in a full size Olds 455 station wagon some years back. Lotsa low end grunt.) Hydraulic roller is the way to go, but they're a tad pricy. To upgrade later, there's some machining that needs to be done to the lifter valley. If you do it now, the cam can be installed later with the motor in the car.
One more thing. These cars corner like roller coasters. Now would be the time to put a baffled
oil pan on the motor. Canton makes a 9 qt., and (I think) Milodon makes an 8 qt.
Oops. What kind of valve stem seals did this turkey put on your Rousch heads. Probably the rubber ones that came with the gaskets. You want to replace these with teflon, or teflon insert seals.
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