I bought a Best Gasket full engine gasket kit, so far all the pieces have been fine. End of yesterday I was getting set up to install the heads and noticed the head gaskets have a 4.25" bore on my 3.78" cylinders (0.060" over 326). This don't seem right. I see Cometic makes a variety of gaskets that'd work better, and I read a couple previous posts.It looks like the stock 326 gasket at 0.040" compressed thickness would work, but don't want to lose anything off the 0.010" trim I took off the heads. The heads are 140's, should have given me about 9.4:1 CR. Could I go with a 350 gasket (3.95" bore) with the 0.027" compressed thickness? Not sure how much the gap at the bore impacts performance. I'm going to call Best Gasket soon as they're open to get the compressed thickness on this one, but it doesn't look like they make a 326 gasket. As usual, any feedback appreciated.
Thinman,No I wouldn't say that 4.250" bore on your gaskets is right. That seems more for a 455 than a 326. I just recently went through this issue, looking for head gaskets. There are several out there that make various bore dimension head gaskets. You might look at summit racing or jeggs, or year one, ames or numerous other sights. I wanted the smallest bore diamter that would fit for my application under the presumption that would leave more gasket material meat in between the cylinders for better sealing.
Yup, Jim, that makes sense. Also makes sense to match it up as close as possible because that open ring also represents a little extra volume that ain't doing any good and lowers compression ratio just a little bit. I called Best Gasket, the guy I talked to said their kit head gaskets are Felpro, and he checked with their 'factory guys' on whether the bore would be a problem and called me back. They said FelPro and Victor are all making these gaskets the same bore now (4.2") and it will be fine. Somehow I'm not convinced, but the only thing I can find that really fits is the Cometic at $200/pair. BTW, the Felpro is 0.055" uncompressed, ~0.049" compressed, which is going to nibble away a little more at compression.Online searching doesn't bring up any other options, and Ames carries the Felpro. Anyone have any other head gasket sources I missed?