The intake manifold issue can be resolved with a adjustable slip collar MSD billet distrib.
There are also Tall deck intake manifolds machined to use the factory height collar distrib. I run a Edel. Victor 454 TD. I also use a MSD with the before mentioned adjustable slip collar. As far as header fit it can be a issue. Nearly all headers need clearanced to clear factory A- arm and Steering linkage on GM ( A ) bodied cars. That said Lemons headers fit tall and short decks alike VERY well. They are spendy but you get what you pay for. My next set of headers WILL be Lemons headers with Nitroplate.
There are also Tall deck intake manifolds machined to use the factory height collar distrib. I run a Edel. Victor 454 TD. I also use a MSD with the before mentioned adjustable slip collar. As far as header fit it can be a issue. Nearly all headers need clearanced to clear factory A- arm and Steering linkage on GM ( A ) bodied cars. That said Lemons headers fit tall and short decks alike VERY well. They are spendy but you get what you pay for. My next set of headers WILL be Lemons headers with Nitroplate.