I am installing edelbrock heads on my 350 ,the place were I bought the heads
gave me fel-pro 1003 gasket .I read the instruction and it gets me to drill
larger coolant passage holes in the centre of the block and the gasket restricts the flow on the outer passages . Should I do this drilling or should
I use another brand like the edelbrock 7310 gasket .
Thanks for your info.

 

Do the drilling.... it REALLY helps.

The hottest place in the entire motor, is the spot where the 2 exhaust ports are right together, in the center of the head. All that heat makes the center cyls run hotter than the end cyls, with the front 2 being the coldest of all. The drilling thing, coupled with an appropriate gasket, delivers more water to that hot spot, and evens out the casting temp of the various cyls.

On some block, rather than drilling, it's easier to use a die grinder to enlarge the hole. You won't have any trouble figuring out what to do.