Anyone have any hints on the easiest way to do this for a given set of heads?

Rich

 

its usually at the pushrod pinch area, which can be measured pretty easily with basic measuring devices...

 

Feel like hearing a wild-assed idea that might actually work?

Set your head on a bench, use some Pam or something similar to grease up the port, then spray in some of that "minimally-expanding" foam you can find at home depot. When it sets you can pull it out from the larger of the two sides. Probably best if you don't completely fill the port, just fill enough to give you a good mold at the pinch point.

I don't know if that'll work for you, but it should only cost about $5 to try it.

 

I'll send you my spreatsheet on this Rich...

BTW if you search ole Mindgame's posts in LT1 tech he got into a heated discussion with Larry Ross about this topic and gave out all the calculations for it.

Bret

 

I vaguely remembered that but couldn't find it.

Thanks for the ideas so far, I may try the foam thing. I'm glad no one said you have to cut the port in half.

Rich

 

CUT THE PORT IN HALF!

That's for, "Not understanding the desire to run 18º heads on an LT1" Rich.

Lame, that's a darn good idea. I'll have to try that some time. One other way you can do it is to use a yankee caliper. Don't know if they have another name... that's just what I've always heard them called. The one on the left is the tool you're after.

Companies also make them with a dial on the end, but those have to be set with a micrometer and have a range of 1".

In regards to minimum cross section and true race heads... most of them aren't smallest at the typical pinch point but usually are smallest somewhere at or before the short side. Just from what I've seen anyways.

HTH.

-Mindgame

 

For performance heads.. 90% of valve area
For street heads........... 85% of valve area

 

Sometimes.....

all depends on the throat diameter... it might be that small might not.

 

Gee, sounds like a great idea! NOT!! If it is what I am thinking it is, (building/construction product type of foam) not a good idea. Expanding anything, be it minimal/maximal, not a good idea. Plus, that material isn't designed to conform, when it comes time to pull it through different contours/sizes. Stretch, it won't. If you care to go that route, at least use the rubber like material intended for that purpose. Naturally, the better products cost an arm and a couple of toes. It certainly will give a view of the port from a different perspective however. Can be very telling. In this case, and for what you are after, I would recommend the outside caliper, as suggested by MG.
My thot was, that (throat dia.) was what 'j' was referring to.

 

Dang I just use snap gauges and a formula I got