High velocity header collectors, are they worth it?

[Jacob Pitt]

Hey guys. I'm in the market for some new header collectors and was wondering if those high velocity units are really worth any e.t. on a stocker. I know the price on these over the traditional collectors is quite a bit higher. Just wondering if any of you guys that have tried them have picked up any mph or e.t. Thanks.

[Alan Roehrich]

What your combination requires will determine whether or not you see a gain. If you have a set of 4 into 1 headers that are the correct primary diameter and length, and your previous collector was the correct size and length, you may not gain much at all, and you may need to do some tuning to gain anything at all. If your headers are not the right size and/or length, then a good merge collector may offer a decent gain. But it still may require some tuning before you realize a gain.

[jmcarter]

There was a good thread started by Wahl recently that had some savvy tech comments by SSDiv6 and others that led me to order Performance Welding's merge collector. Think we run similar combos even (360 Volare??) so I can give you input as soon as I get the car back out. Suppose to be worth 4 or 5 Hun. Suggest you call Mark and discuss with him and read the articles on his website.

Alan is correct as well; I've only got a 3" collector and step primaries that are all over the place so I don't expect full gains until I get some true equal length tubes as well.

[Wade_Owens]

Jacob, do not buy anything until you talk to Mark @ Performance Welding. Trust me, he will get your header and collector program in order!

Wade O

[Jacob Pitt]

Awesome! Thanks for the info guys. I'll give him a call and pick his brain a little.

[Jeff Lee]

I had some custom headers built by REF who is recognized as a pretty good builder. Based on my dyno inputs, he selected a merge collector with a big venturi and big outlet. Car felt lazy but it was pretty close in ET to the headers I had previously (Headers by Ed).
I called REF and of course he said my engine didn't make the power I claimed and he sent me a smaller venturi, smaller outlet. It immediately had a fuel starvation problem off the line (bowl running empty) but still had the best 60' ever. I installed a larger needle and seat which I had been wanting to try (but never seemed to have a problem) and immediately picked up .200 over my previous best ET with the best incremental's I had ever experienced.
So the point is, the collectors can make a HUGE difference, more so if something was not quite right previously.
And I have seen Marks work and he does great work and his performance is exceptional. He incorporates large sweeping bends with as much of a straight shot off the heads as possible, even if it means not being a "true" exact length primary tube design. To me, thats the way to make a header.

[Chris Hill]

Is equal length headers really all that important, especially on a stocker with a dual plane intake?

Reason being is on the stocker with dual plane, the intake runner length is all over the place and I thought the exhaust AND intake runner lenght need to mesh to get the full tunning effect.