just to be 100% sure 5.8 efi plenum to intake manifold aluminium six bolts please verify torgue lb on bolts i have a spacer inbetween them with total 2two gaskets i believe thats where my low vacuum condition if from I DONT WANT TO DESTROY THE THREADS please reply cheers i might just tig weld the spacer to plenum so utilize just one gasket , i changed all vacuum lines already with a little improvement. and will remove a seperate throttle body spacer tomorrow might improve vacuum in plemun THE LOW VACUUM CONDITION IS WHEN LOAD IS APPLIED DROPS TO 0_ZERO I HAVE A VACUUM GUAGE TO REFER