I don't know if this has been mentioned and I'm not going to read through the entire thread, but if installing EFI exhaust manifolds to a carbureted block, the Mahle gasket is the easier to use. Less likely to tear and or leak.

We have used the Fel-Pro (2 piece) gasket twice and have torn it both times.

This is if you are working with the motor in the truck.

If on an engine stand, I assume either would be fine.

 

Understood! back in the 70's the "family" lived and operated the company out of their home in Cedar Glen (California) in an area known as Hook Creek... near Lake Arrowhead.... the father who started the company at one time was a very good machinist but IIRR became an alky in his later years....worked at a gas station in Lake Arrowhead and he would come get fuel.... appeared to be a partial to full deuce most of the time and was not a "nice" person... they got into financial difficulties, IIRR they filed for bankruptcy, the son took over and they kinda disappeared from view for a few years and IIRR the son lived in the desert...Temecula IIRR..... when after the dad (Jack) passed away he officially moved the company to.

 

I had no issues and had mine on and off a few times.
EFI exh factory log intake manifolds.
Were you using the factory bolts & washers to bolt them to thehead?
I used studs, factory thick washers and nuts.
Dave ----