[Motorhead]

I've just started porting my 460 heads (D3VE-A2A) tonight, and I've been extra careful not to go too deep anywhere to bust through to the water jacket. I was wondering, if I did happen to go through, are the heads scrapped? Or is there a way to save them?

Basically all I've done this far is completely grind away the thermactor bump down to even with the lowest part of the roof, and also removed the bump that runs across the roof at the base of the thermactor bump. I also ground all the excess off the valve guide boss and also the edge near the valve seat where the factory machined out the hole for the valve. But I am afraid to grind away at any flat surface that doesn't protrude into the port like the bowl and the walls. I checked out the pictures at http://reincarnation-automotive.com/ and they were really helpful, but you can't really tell how much the guy actually ground away in the pictures. Plus, I see a lot of epoxy in the pics, which makes me think he went too far, which scares me, lol!

I guess I should borrow a digital camera and take some pics and show them on here so maybe you guys can give me some pointers. The last thing I want to do is ruin these heads... my brother donated them to me, and he'd already had hardened seats and some other machining done to them, so they are in really good shape. But, I don't want to be taking all this time to do the porting and not get much out of it because I wasn't aggressive enough with the grinder.

Sorry for the long post, I'd appreciate any input (especially from someone who had worked on BBF heads). Thanks

 

[Troy Boswell]

I've done one set of D3 heads so I'm no guru, but I'll share my opinion on the subject. If it looks good, leave it alone. For us street guys, I don't think every last mm of material needs to be removed. I did nothing to the intakes but polish and remove a little bit of the guide boss. I attacked the exhaust much like what you've described. I drew a picture of what I did and have it on my computer at home. I'll try to remember it tonight and see if somebody here will post it. It's not a digital image, but you'll get the idea. Compared to stock, you can't hardly "hurt" an exhaust port. If you do go through, I would say they are junk. Longevity of any repairs will be questionable. I know some machinist around here that won't even look at a cylinder head if you say it's cracked. They know how hard it is to do repairs in that type of enviroment. Be cautious, but you can grind a shitload of metal away without hurting a thing.

 

[Motorhead]

Thanks for the reply Pale Rider. I wasn't planning on doing much to the intake either... just take some material off the boss, smooth the ridge above the valve seat, and gasket match the port opening. Obviously the main problem lies in the exhaust port, so that's where I wanted to make sure I cleaned it up good enough.

I really wish I had access to a flow bench, just to see how much of an improvement I've made, so I could actually see when it's 'good enough'. Also that would help to get all the ports close to the same. But I think I'd just get greedy looking for those last couple CFM if I had something to test them on, lol. I'll stick to being conservative, and just take off the huge obvious restrictions.

One other question; there is a vertical bump on the right wall about an inch from the port exit that looks like it can be ground all the way off to flush with the wall. It doesn't have a bolt hole behind it, so the only thing I'm woried about is breaking through to water there. Is it ok to grind that all the way down to even with the port wall?

Feel free to email that picture to me, and I'll post a link to it here in another reply. Thanks.