okokok... Header Question

[Earlsfat]

Alright here's the deal.

The heads I've got are of a 71 vette (pretty sure they're 71's, the guy said they're one year only and VERY good heads... for whatever that's worth) that have been ported "a LOT, but done well".

They're on a 454, with a comp cams cam (not sure which yet, still looking for a stamp on it) with a 3" exhaust.

I'm guessing what I have will work ok, but not sure if it's right. The new ones are the same dimensions as the old headers I took off.

Question: The header's I got are Dynomax Ceramacoats - 1.5" primaries and 3" collector, is that right or should I be looking for a bigger primaries on the headers since the heads are ported pretty heavily?

[goldz28]

Now I am no mechanic but I would think you would want your headers that go to the heads, the opening to be the same size so you don't get a lot of turbulent are affecting the exhaust gases leaving the heads. But like I said I am no mechanic.

[Morley]

For a big block you want 1 7/8" primaries...I'm running 1 3/4" primaries on my 350 and that is the recommended size for a well built 350.

[Earlsfat]

So I should be looking for something around 1 7/8" - 2" into a 3" collector?

(I shouldn't be looking at going to 3.5" exhaust or something like that should I?)

[1986Z28]

1 7/8" atleast 3" collectors should do and 3" mandrell all the back would work, btw really sorry to hear about earl

[Earlsfat]

Thanks, it been really hard to accept he's gone.

Thanks for the info guys... gotta make some phone calls now. (I KNEW I shoulda asked first... DAMMIT!)

[Morley]

Yep, go 1 7/8" primaries to a 3" collector and 2.75-3" to mufflers and out.

[Earlsfat]

Hmmm... It has a full 3" exhaust on it. WHICH some jackass put 2.5" pipes on after the mufflers to make it street legal. I think I'm going to put the turn downs back on (after the mufflers) and get rid of the 2.5" extensions.