Anyone have some flow numbers from some ported aluminum L98 heads??

 

I just ported/polished my set of Al L98s. I wish I had a way of doing before/after testing to see if my mods did any good!

I followed SOME of the recommendations in the David Vizard book, but others didn't seem to make sense. For example, it sounded as if he had to do more work in the exhaust than the intake, but mine sure didn't seem like they needed much more than a clean-up. The intake side however, had a lot of sharp edges, not to mention the fact that its a much longer tunnel of twists and turns, and had the pushrod bulge to deal with. *shrug*

Another thing in the Vizard book is the picture where he shows the finished, polished chamber.. With the square "wedge" above the plug hole ground away! Why would you eliminate that?! seems like it would really increase the chamber volume and lower your compression. I assume the only reason why they put it there was to fill up space and give you higher compression!

As long as I'm talking about it.. He speaks of the intake valves needing a back-cut, and generally requiring work to make them flow good. My intakes didn't seem like they needed any help at all, while my exhaust valves had a sharp parting line about 1/2 way from the seat to the stem. This seemed like something that needed smoothing out.

anyway.. search for "l98 porting" on this board and you'll find some previous posts that talk about flow numbers.

 

I've got some numbers up on my website. Got mine ported from SDPC. I've got the stock numbers as well as the ported numbers. To find the chart, click on "Modifications" and scroll down to phase three. Then click on the link for the cylinder heads.