I have a set of block hugger headers that I was going to put on my SBC. I noticed that the heads were square port and the headers were round port. They will fit and the gasket shows that the shape is pretty close. How will this effect my performance? Should I off the headers and get square port headers? I haven't noticed any square port block hugger headers in my catalogs. Do they make square port block hugger headers?
as long as the ports are similar sized you should be fine performance wise. The real test is getting gaskets to seal...
You won't have any problems. Performance isn't really what block huggers are about in the first place, they are mainly for fit and convenience. We make most of Our Block Hugger type headers with an Oval Port configuration. Don - Doug's Headers/Patriot Headers
If performance is not really what block headers are about, will they give any improvement over stock cast iron exhaust maniforlds?
Probably not that you can tell by the seat of your pants. For round (or Don's oval port) headers I like Fel Pro Performance 1426 gaskets. Hey Don, I bet I put a set of your headers on a customers car last week. Larry T