BlueTwoToneCorvette

1985 C4. I bought the Fel-pro gasket kit and the head gasket set is 7733PT2. This is listed as having a compressed height of .039. Everything I see online is around .04 or so. I read on a website that the OEM gasket for a 1985 L98 C4 is .021. Don't I want to use the OEM thickness?

The old head gasket had been replaced and the edge is .033.

I read that the OEM gaskets were a metal shim type and were not durable. I don't know anything about gaskets, so I have no idea what to order. I'd like to get something closer to .021. Anyone familiar with Victor Reinz 1178BS? Thanks

VikingTrad3r

hi two tone, i just finished mh 85. i used the same kit you referenced. worked excellent.

the oem i belive were actually .015. metal shim. felpro 1094.

in the end, i used the one in the kit u referenced cause it was less hassle and i did shave a smidge off doing my head machining which i did by hand.

fwiw, i used hylomar everywhere. worked great!

Joe C

I just finished the head gaskets on my 85. FWIW, I used the fel-pro 7733PT2 as my replacements. you are correct on the .039 compressed thickness, and somewhat wrong on the OE steel shim as being reliable - mine lasted almost 30 years. anyway, by using the thicker fel-pro 7733PT2's, you'll loose approximately .5 on the compression ratio - performance wise, YOU'LL NEVER FEEL THE DIFFERENCE. my 85 is as strong as ever - even with 155K miles on the clock. unless you're tracking the car, in competition, and looking for every ounce of HP and torque, any quality head gasket will work just fine. just make sure all surfaces are clean and flat (within specs), and go for it. BTW, I recommend new ARP head bolts and sealant. no need to over think this....

VikingTrad3r

^^^^ joe was one of the guys who walked me through mine. great advice. i was just short on money so i reused mine.

BlueTwoToneCorvette

You used the hylomar on the felpro blue head gaskets?

I thought sealant was only needed on the thin metal shim type like the felpro 1094?

I looked up the felpro 1094 it said it was extra thin .015 for raising compression. It's not expensive, I would try it to get the compression back to stock levels. Thanks.

VikingTrad3r

pretty sure im the only one who has used hylomar.

i did it because i read everything i clould and it still made sense for me. i did my own manual head decking, and i wanted to have a sealant of some sort, hylomar came out on top for in mh analysis for a few reasons.

time will tell if it was smart or not.

the manufacturers all have thier recommendations, i dont know if any recommend coatings of any type. yet people still use the copper or aluminum spray. some use hylomar. some use nothing. hylomar is the "most forgiving" and as i am a noob it was my first time, i wanted a sealant that--if i had to open it up again--it wouldnt be a huge pita, hylomar is re-usaeble.

turns out i did have to go into the valve covers again as i did my lash too tight. the hylomar and cork (yeah, cork) worked excellent. it came aprt, and went back together, easily with no cleanup or mess.


lots of different ways!

BlueTwoToneCorvette

I ordered this. It came marked as Victor Rientz. $20 each. I was surprised to find that it was an identical match to what I took off the engine.

Clevite CLE-5746
Head Gasket, Nitroseal, 4.125 in. Bore, .026 in. Compressed Thickness, Chevy, Small Block, Each
(Mfr. #: 5746)

mlm0

I'm changing out my 89. The SPECS tell me it was a .21. I went to chev dealer and he order me one out of their corvette part book, but it's .51. I had him recheck , and he told me that's the correct one. I'm confused, I only want to do this one time and I don't want to lose any compression

Joe C

BTW, its .021 and .051, not .21 and .51. my thought is the thicker replacement gaskets allow for a machine shop milling the heads for flatness. trust me, even if you don't run your heads through a shop, and you use the .051 you'll never feel the difference in compression or performance.