mis matched heads and a vacuum leaking gasket?

[Grumpy]

I am having a intake vacuum leak at all the runners were they meet the head. Tried 3 different gaskets and 2 different intakes. Doesn't seem to stop. Any ideas the heads are suppose to be compatible. It is a rebuilt motor came that way from the re builder.

ON A 30-40 PLUS YEAR, OLD BIG BLOCK ENGINE ITS NOT ALL THAT RARE TO FIND MIS-MATCHED COMPONENTS AS PREVIOUS OWNERS OR MACHINE SHOPS HAVE BY NOW HAD THE OPERTUNIUTY TO MAKE A FEW REPAIRS OR PARTS NEEDED TO BE REPLACED,
the first obvious question is where . on the gasket around the ports.is the intake to cylinder head gasket leaking
if the heads were angle milled or decked more than a few thousands of an inch the intake will need to be machined to duplicate the angle and clearances

https://www.napaonline.com/en/p/BK_7001006


http://garage.grumpysperformance.com/index.php?threads/milling-heads-and-intakes.2988/#post-7845

http://garage.grumpysperformance.co...-peanut-port-big-block-combo.2900/#post-61085

http://garage.grumpysperformance.com/index.php?threads/big-block-head-comparison.319/
CASTING NUMBERS
353 049 .....73-84...oval...OPEN...454, 122cc chamber, 255/119cc ports

336 781 ....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports
the heads are very similar, now obviously running two different heads with different ports and combustion chamber sizes if not ideal but your hardly the very first guy to do that, the vacuum leak, its more than likely the result of a stock intake on milled heads and theres an angle difference or the blocks been decked on one or both sides and the intake manifold seats on the block china wall and won,f clamp to the heads, if the lower intake seats on the block before the intake gaskets firmly compressed youll have leaks at the runners
http://garage.grumpysperformance.co...stalling-the-intake-manifold-distributor.464/