flowing, porting

[maytag]

Originally Posted by The Radium King

thanks - some potential inthe heads, hey? i was wondering more if there is any need to work the intake or exhaust manifolds where they mate with the heads.

you're talking about what I've always called "port-matching". I have never seen a motor that was machined or cast so precisely that it couldn't benefit from a little work that way. But I'm sure the Porsche Purists will tell us that these motors were all hand-ported / matched before they were assembled on a shaker-table...... ::eye-roll::

If you don't have experience with port-matching yet, (you probably do? but just in case) one of the first rules I use when looking at doing the match work is that adding material is just as important as removing it, in most cases. Here's why: if you simply scribe the ports to each other, and then grind to the scribe-line, as most beginners do, what you'll inevitably end-up with is a "bulge" at the port, where you've made it bigger than the rest of the runner, on either side of it. This can be HORRIBLE for velocity. And depending on your cam duration / overlap numbers, it can cause some real rough-running issues under certain part-throttle conditions, where that bulge "absorbs" a pulse. Much better to blend those ports together by adding here, removing there, until your ports are the same shape and match perfectly.
If you check the best porting-work, you'll find the use of epoxies is very common.