Hello, sir!
Dang, that stinks... so an El Camino went out of el camino just to smack your car?? Sorry, terrible joke, but I couldn't resist. Seriously though, I'm glad you're bringing her back to her former glory and we'll look forward to a few pics of the finished car for sure. So yeah, as far as head mods... Opening up the port entrances can bite you in the butt in certain applications, and often times the effect on flow is hardly worth the time spent. I don't think I'd put a ton of effort there unless the discrepancy in head port to intake manifold dimension is quite substantial. On a small block Ford using OEM heads, the gasket is quite often much larger than both. There MIGHT be something to gain there if you were in need of more cross section and trying to feed more cubes, and took some out of the pushrod pinch area and worked the entire port, but honestly in this application, I would suggest simply making sure that the head entrance isn't smaller than the manifold exit, which even with most aftermarket street type dual planes, it won't be. If it is, then a guy can blend out the head port to match, yes...you just don't want a dam at the end of the intake port for your charge to collide with. And in some applications, even the effect of that is debatable. Most gains are to be had right under the valves, and the valve job itself, and on those particular heads the exhaust side is the port that needs the help. I guess I got way ahead of myself and I never really asked, which was dumb of me, but what are your actual wants and needs for this motor? I ask because depending on that, those heads may be just perfect as is! I mean if we're talking about a basic overhaul and just making it new and built to cruise and live life easy...run 'em. If we're talking about near duplicating the 271hp motors...run 'em. If you're wanting a max effort little screamer, then yeah okay...you'll probably wanna get out the carbides and cartridge rolls, along with doing some screw-in studs (or get Trick Flow or AFR on the phone;-)). But for mild street, they'll do the trick stock, even with the 1.84/1.54 valve combo. I hope at least something is helpful here...I'm just sharing what I've gathered from my own experiences, but perhaps someone else will weigh in and have totally different info...ya never know!