I just put a 94 5.0 engine in my 72. I used the same carb and intake and distributer from my 72 302. I plugged the back of the heads with a bolt (air tube holes). Started it up today and she won't idle unless it's almost choked 100%. I am thinking vac leak. Has anyone had the same issue with a newer motor? Intake bolts tight, new carb base gasket and carb secure. Timing set. Any suggestions? John
also the 72 distributor gear is not compatible with the 94 roller cam. you need a steel gear distributor. a good option avaiable from the parts store is the 85 mustang gt 5 speed manual trans distributor. its a duraspark II one that is for a roller cam. it will work with msd boxs or dura spark box.
And a steel gear for the distributor... At least if you don't want to chew up the iron one that's on a orig dist...
Thanks guys for the advice. I replaced the dist gear with a steel gear before putting the motor in and I am using the 5.0 HO firing order. It does not back fire or miss it just won't idle.
the newer motor should not have any problems with your carb and intake. it could be a vacuum leak, timing, or carb issues.
Hey John, make sure all of the vacuum ports under the carb are plugged which I'm sure you already have done. Other than that check for vacuum leaks by using some carb spray and squirt around the edges of the intake and carb base while it's running to see if the rpm changes. Did the intake get torqued down evenly with the correct gaskets? Try a different carb if you can't find any vacuum leaks. Inspect the carb for cracked base or mismatched gasket to manifold. EDIT: Since you have to use the choke it sounds like it's either getting too much air (vacuum leak) or it's not getting enough fuel. Have you checked fuel pressure and float level in the carb?
are you using a phenolic carb spacer? I had a foxbody a few yrs ago that I got because it wouldnt run right, the egr port was not plugged/capped on the intake and it eventually melted the spacer causing all sorts of nightmares until i pulled the carb. looked ok externally and when i pulle dit i found the melted mess under the carb. a longshot but worth a look.? could also be an intake gasket leak.
Thanks bud. Gonna pull the carb off and make sure no debris got in the carb. I will let you know. Thanks for the offer.
Problem solved Thanks for all of the responses and suggestions guys. The issue was a vac leak from the intake combined with a timing issue. All are corrected and the car is running fine. Now it's time to put the 9inch locker 31 spline rear in. Once again thank you for the help !!! John
