Ported Exhaust Manifolds

From: https://rivperformance.editboard.com/General-c1/Welcome-f1/THANX-HOPE-THIS-SITE-WORKS-OUT-p11829.htm#11829

"This MORNING, I spent a couple hours porting my extra front exh manifold (thanks AA) and I can hardly wait to swap it on. Needs cleanup/paint first though. The stock front has unbelievable restriction at the openings, ridiculous casting flash to clean out. Alternatively, you can get a "PowerLog" front manifold from ZZP. It is a compromise between the stock cast iron manifolds, and going to headers. The rear exh manifold is a much less restrictive steel piece. I may do a Powerlog next year, but wanted to try a ported front first."

Hope it works out for you. let us know if you feel a difference. Dave, you've been trying to say "no" to modding your Riv, but it seems you just can't seem to put down the tools!

AA wrote:

...... Dave, you've been trying to say "no" to modding your Riv, but it seems you just can't seem to put down the tools!

Yeah, I know... my problem is that I like to see the results of my mods at the track, but since the Riv is my DD, track appearances will be limited, and may in fact be finished. I can't afford any major breakage to my DD. So I will likely continue with a few more mods, nothing major like cam, rockers, IC or headers. If I'm not satisfied with the front mani, I may go the P-log route. Want to run a 3.5 as a final pulley change I think. Though a summer 3.4 and winter 3.6 might work out ok too. We'll see.

And thus, my attention will turn back to getting my 68 project moving again. Tomorrow it will TAKE OVER the garage! The van and Riv will be relegated to the driveway, and the GS will move to the middle so I have lots of working room. I've got 3 weeks of vac time coming up in Aug/Sept/Oct, so maybe I can make some headway. I want to see that thing in the 14's.

I think you'll find running your bigger pulleys in summer will work better. I run the 3.4" in summer, 3.3" when it's below 75º, and 3.2" below 55º. It seems the cold temperatures offset the added density in the winter months... to a point, I'm sure. I've run zero KR at WOT in 25º temps. If there was any traction to be found, I'm sure the car would be good for a 13.5 in the quarter.

Of course, that makes sense.

So anyone else here play around with porting their own front exh manifold? I think I've done a fair job of it, and was going to post pics, but turns out "our" digital camera got left behind 4 hrs from home a couple weeks ago...

I DO think I could use some finishing touches though. It's a bit rough in places, and some more leveling out should be done. Is polishing one of the steps to consider? What would one use to do it? I'd like to see some pics of finished ported manifolds, will have to start searching.