I have a 79 F150 w/ 302 w/ 2v Motocraft carb and EGR. I've been trying to find a mysterious exhaust leak forever. I'm not totally certain it is an exhaust leak. I have over time replaced the exhaust manifold gaskets. Removed the Exhaust manifolds and had them both surfaced. Used nice new bolts. It's not a real loud one. The truck doesn't have the greatest oil pressure, but the noise seeems consistent w/ an exhaust leak and not ticking lifters. I heard one recently that really did have ticky lifters. This is alittle more spitty. So I turned my attn to the EGR. Earlier I was battleing lean running conditions, that led to the carb being rejetted as well as ignition improvements. The Carb ppl told me to replace the EGR that it was coming on too early. So I did, and it had a variety of orifices to use depending on the OEM part number. My Engine had been rebuilt in 1990 according to a tag on the door jam, and anyway the OEM part number wasn't on the list. First I used the same sized orifice as was in it before. I was expiriencing pinging when the engine got hot. Recently after thinking about the system I took it apart and put in a very small orifice, which has pretty much conquered the pinging. However its become apparent to me that one of the bolts that bolts on the EGR was stripping the threads in the aluminum spacer. I bought a new gasket set for the carb and EGR (Fel-Pro) and replaced them yesterday. No change, still the leaking sound. The old gasket between spacer and EGR showed carbon evidence of leaking. The new gasket was in for about 3 hrs of driving and when I pulled it apart I didn't see the evidence. So today, I got Helicoil for the stripping out hole, and some Orange/copper hi heat RTV to seal the gasket in. After bolting it together I took it apart again and used copious RTV and two gaskets. Its sitting overnight to cure since it was not warm today. Any feedback or ideas? The next step is for me to use the 4V edelbrock performer manifold I have and the 600cfm Edelbrock carb. I hate to give up on the Motorcraft, because it's running well and been jetted for the motor. BTW... this is the second post I've composed today, apperently the other one didn't make it on to the board, perhaps I didn't submit it before closeing out.

BBT

 

I just replaced the spacer on my 76. Did the same as you replaced header gaskets ect. Strange exhaust noise stil there. It was the aluminun spacer for the EGR had a big hole in the bottom. Someone before me must have tightened the carb too tight and cracked the spacer. I looked for one in the u-pick JY and of course this spacer was only used on 76-77 Mine is a 360 so don't know about the 302 but there where plenty of 302 in the yard. Called dealer of coures this item was no longer made but he gave me a P/N. This co in OHIO Green Sales (800-543-4959) all OEM Ford part's had one in stock $30. Must have been a problen for ford because the one I recived was cast. It's fixed and quiet as a mouse now. Good Luck