badone07

I picked up a set of 193 heads from a 87 Suburban. I know, I know... I got tired of looking for a good set 083's. For the $40 I paid for the set, I'll cut the swirls back to the guides, some bowl work, gasket match the intake and polish the exhaust and combustion chamber. Since slightly stepping up the cam and springs, I removed the pressed in studs and will tap for Mr. Gasket type screw in studs. Might be overkill, but I do not want to have to take them off, since I might put 1k miles on the truck a year. I've seen conflicting statements as to their cc size of the 193 heads, so I'll cc them myself. Since they are going on a 350 for my truck, I think they'll be fine.

Anyway, after disassembling them, the intakes had positive seals and o-rings, while the exhausts had reminents of the o-ring seals. I plan on putting viton positive seals on both the intakes and exhausts. The guides OD measure in the .560-.565 range. I measured the ID of the old seals in the .525-.530 range. I can get the viton seals in either .530 or .562.

My question I guess would be which seals do I get? The band on the seals stretches and looks the same as the seals I removed.

Thanks,
John

boogie

I always cut the OD of the the guide bosses to .530 and reduce the height at the same time with a cutter available from comp,crane and others and use the positive seals from felpro,however you can install them as is,just a tighter fit. Don't have part#'s handy but i use the blue felpro's on the intake and thier light tan colored high temp viton seals on the exhaust.

I have CC'd that particular casting and it spec's out to 64-65cc

badone07

Thanks Boogie. I think the people who claimed they were 76cc, never owned a set. Most likely just echoed misinformation from others who never cc'ed them. Guess I'll look for the felpro seals.

Thanks again,
John

Damon

I agree with Boogie- .530" is a real common diameter to shoot for. Lots of seals available to fit that dimension.

I should mention, however, that if you're talking about the soft rubber-looking black posi-seals (which I beleive are what you're referring to as "Viton" seals) you should leave it a bit bigger than .530. They like to have a slightly larger boss so they grab on nice and tight. If the spring around the base of the seal doesn't put some decent pressure on the boss the seal can "ride up" the valve stem in my experience.

In other words, try using the .530 Viton seals on an UNMACHINED guide boss and use your "feel" to tell you if it's just a snug fit for them or if you're really pushing them beyond their limits. I've used .530 rubber (Viton) posi seals on stock, un-machined guides like yours with excellent results in several cases. They got a lot of "stretch" in them around the guide boss vs. a hard plastic posi seal- those you must machine to size.

badone07

Thanks for responding Damon. I was thinking about using the .530 seals on the .560-.565 guides also. I sent a few emails back and forth with the seller. He suggested that I use the .562 metal clad viton seals, instead of the more universal type .530, where the retaining ring expands. He said the .562 metal clad were a OEM replacement. However, the universal type looks more like I removed from the heads, just black instead. I borrowed some pics off the internet to show the two different types down below. I'm just not sure if the .530 metal clad will stretch enough to fit over the stock guide boss.
Metal clad type:


Universal type:




John

boogie

The metal clad seal you have pictured is a very good seal and will fit the stock guide bosses but they will be too large for .530

8Mike9

Hmmn, about the CC size...I happen to have a set of those in my garage, and laid them next to a set of 461's I had...461's are supposed to be 62?cc IIRC, anyways, the CC's looked larger on the 193's.

Maybe that big ole spark plug boss protruding into the chamber makes up the difference.

I guess I could CC them, but I don't see the need..too much grinding to get the vanes out, IMO, for what they are worth after it's done.

boogie

Yes, the chamber looks like the 74-76 variety, so much so i cc'd them myself to know for sure

badone07

They looked like 76cc to me too. I'll cc them anyway, as soon as the graduated syringe I bought gets here. I don't mind cutting the swirls down. It's much better than getting another set of 083's, bringing them down to the machine shop, 40 miles away. Waiting a few days and getting the dreaded phone call that they are cracked. I've been through 4 sets of heads so far, with the same results. So far for me, the 083's have been good for wheel chocks. Well at least the ones that I have unfortunately come across. I also just have to tap for screw in studs. Then I'll drop these off to get done. The way things are going, I'm sure I'll come across a good set of 083's right after I break in the motor.

Which a few minutes ago I found out my new Proform #66783 Rocker stud remover & tap alignment kit from Summit isn't accurate as claimed on the package. Pulled the studs fine. The tap doesn't line up when using the arbor. Always something.

I didn't plan on getting the bosses cut. The guides feel pretty good and most likely still with specs. I'll let the machine shop determine if any need replacing. Therefore, I guess I'll get the .562 metal clad viton seals. Thanks for all the help guys. I really appreciate it.

John

AJ_92RS

I have those heads and cc'ed them also.

Mine are casting #193, and they came to 64 cc's.

badone07

AJ_92RS, I emailed a few questions to you a few weeks ago. Maybe you didn't get it. KFoley has been a big help outside the boards, regarding these 193 heads, since 083's don't like me. I read about Dyno Don's previous experience with them too and hopefully he answers on the other thread...
https://www.thirdgen.org/techbb2/sho...hreadid=192114

8Mike9

So do you guys think it's the sparkplug boss that "fills'em up"?

Just curious.

Did any of you guys flow them with the Vane left in?...I'd be curious to see what they'd do up to about .42-.45 lift.

AJ_92RS

That's exactly correct.

That's what we're trying to find out if Dyno Don did.

Damon

The top picture with the metal-clad seals won't stretch as far as .560 if they're designed for .530. You'll split them, if you get them on at all. Bottom ones will stretch to fit.

badone07

Yeah Damon, I bought the metal clad (top pic) in .562 for the stock bosses.

badone07

The .562 metal clad vitons fit perfectly and snug. Came with a set of 8 intakes and 8 exhausts. All for only like $23 shipped. Looking forward to cutting the swirls out of the ports. Thanks again for the help.

John