[aumoore]

Here is what I did
Used very low milage 1997 Mountaineer 5.0 $1000
sold EFI crap for about $200 net
bought Holley 600 vac secondary $225(higher now)
Edelbrock Performer rpm intake $145
Mallory Unilight distributor $225(will run without box)
Trick flow stage one cam $140
Motorsport fox conversion kit $200
MSD coil $35
Moroso plug wires $40
motorsport valve covers and air cleaner $120
rebuilt 1985 mercury water pump $17
March alternator bracket $62
motorsport flywheel $100
rebuilt 1970 ford alternator $20

all the above netted in 267RWHP and 285 rwtq on a dyno. I have a 1985 corvette IRS so I can brobably day at least 17-20% drivetrain loss whick puts the flywheel numbers at around 321HP and 343TQ. I come up with a total of $2129 after I sold the EFI stuff. Now this motor had 12 miles on it from a FoMoCo test vehicle whick I doubt any still exist but there are a lot of V8 Exploders and Mountaineers with the 5.0 with the GT-40 or GT-40p heads. You should be able to find a good used Exploder/Mountie motor for under $1k and it should have had a pretty easy life compared to a GT stang.

300rwhp will probably require aluminum heads and a more radical cam. I do not think you realize how fast a Cobra can be with a stock 225 flywheel HP 5.0 motor. In a FFR that weighs about 2200# that is under 10# per HP. My car weighed 2450# on the same scale Engineer Ed's FFR weighed around 2200#. They will both get around a track pretty good. He does have a stroker(347) with ported GT-40 heads and he was over 300 rwhp.

I have since added a Mallory Hyfire digital box, Canton road race pan with windage tray and FMS roller rockers. I can tell the engine has more power so I may be pushing your goal.

Look for a GT-40p head motor and you will be pleasantly suprised.