I have a set of 6x 4 castings (i believe they're 1977) that I'm dropping at my machine shop today to get cleaned and checked for cracks. I want to run these on my 455 and use the stock cast iron intake that's on the car now (with 47 heads). I can't remember the exact date, but the intake is around a 68 - 69 4 barrel cast iron intake. Is this a direct bolt on with the 6x heads, or is there some nonsense I have to deal with on the exhaust crossover -- seems like I read this somewhere. Thanks! -paul

OK, I just read the Jim Hand article on this and it sounds like a leaky spank with the stainless and silicone. I don't mind the effort, but I'm concerned about the results. Is there a better solution to this, like running an Edelbrock Performer or something like that?

If any of you guys have done the ho-made block off thing, let me know how well it works. Thanks! --paul.

I'd go with the Performer.
Not only will the performer run better, it'll drop a bunch of wt over the iron intake.
The cross over fix is ok I hear but personally never done it.

I've never could get a performer to beat a 68-72 factory intake.
Nearly drove me crazy do to the wieght factor.
But the plenum and runners are smaller.

As far as early intake to later heads.
Fill exhaust x-over unless you drive all winter.
Not needed during summer months.
And should be done if using hedders.

The Performer is a better match for the 6x heads.

Thats what i had(78 TA/X7 400 w/6x-4's). Stock cam.
A stock 68 and 70 intake ran better.

That is a matter of opinion. The Performer is a better match with the gaskets.