69 Mach 1 Engine cutting out issue
 

Here is the problem. My buddy just installed a brand new 351w stroked to a 418 motor along with a TCI automatic transmission in his 69 mustang. Car started out running well but after a bit of driving we noticed a huge problem. When the motor hits about 4500-5K RPM's when accelerating extremely fast, the car seems to pull and forces the motor down to cut down to about 2K RPM's. My buddy and i uploaded several videos to youtube for people to check out and perhaps give us some advice on what could be the problem. We just replaced the dist and added an electric fuel pump thinking the problem may be solved but not so. Anything helps! Thanks for looking!:)

YouTube - Mustang cutting out at high rpm
YouTube - Mustang Cutting out at high rpm

Re: 69 Mach 1 Engine cutting out issue
 

Appreciate the few people who looked at this thread but we found the problem. A little brass piece in the carb was restricting fuel enough to cause the car to cut out at high RPM's. Problem solved!

Re: 69 Mach 1 Engine cutting out issue
 

Glad to hear you figured it out. That would have driven me crazy!