Myth or does it actually work? I can't seem to get a clear answer, does anyone have dyno results?

 

do a search people have had this post tons of times

 

I had mine ported when I did the h/c/i swap I don't think its needed, but its not going to hurt anything. I also had it ported for my 58mm TB.

 

- I'm not certain if this has been mentioned here before, but there seems to be a difference in LT-1 intake manifold castings. '94 and earlier intake manifolds have larger port openings at the heads than '95 and later.

The '95 and later have enough meat to allow them to be safely gasket matched, but the 94 and earlier models need much less work to get there.

-Jay

 

Ya, it has. Earlier is larger overall, due to the 'crisp' rectangular shape, although length/width dimension is the same. Port opening shape of later LT1 manifolds took on shape of oem LT1/4 head port openings, making them virtually identical to LT4 manifold ports. BTW, I believe it was not coincidence, that the casting change on the LT1 manifold, was done about the time the LT4 manifold was put into production. Internally, the two are virtually identical.