http://store.summitracing.com/partdetail.asp?part=MRG%2D1131&autoview=sku

Or would the big bore cause problems on a little bore engine?

Those are not 4.370 bore size. I odered them for my 496 and they were the same size as GM shim gaskets and barely clear a 4.310 bore. I also had fitment issues with the 1131's and that is why I went to the GM shim gaskets. The 1131's that I received hung over in the bores and did not line up with the dowels properly. Just my experience from last spring.
Jeff

I used the old Felpro 8180 pt2 head gaskets on my 408. I think they are 4.25 bore so they worked better on the 4.15 bore motor.

What thickness are they? I wanted to run the original shim gaskets for the 1970 396 L34 for a 10>25:1 c.r. but the dealership says they're no longer avaliable. :confused:

No I'm sorry I was wrong. I just remembered I had an old one out in the garage and I checked it. It is a 4.37 bore just like the shim ones. It also is a .040 compressed so it won't help you. For some reason I thought they were smaller bore. I know that was what I used because I wanted the smallest bore gasket I could find.

I'm going to be looking for a steel shim gasket for my 402 as well-curious as to what you found that worked??

Just went and measured my 1131's and the GM shim #14015351 as I have three sets of these. The bore diameter at the narrowest is 4.330 and is wider where the notches are for valves. You are not going to get these gaskets on the block with a bore of over 4.330. I mentioned before the GM ones were very, very close to hanging in the bore at 4.310 (+.060 454). GM measures .022 compressed.
Jeff

Just went and measured my 1131's and the GM shim #14015351 as I have three sets of these. The bore diameter at the narrowest is 4.330 and is wider where the notches are for valves. You are not going to get these gaskets on the block with a bore of over 4.330. I mentioned before the GM ones were very, very close to hanging in the bore at 4.310 (+.060 454). GM measures .022 compressed.
Jeff

Jeff do you know if the #14015351 shim gasket is the same one used on 1970 350 HP 396 big blocks?

I do not know that for sure, sorry. I have never had a 396 so I just can't say for sure. Like I said in earlier posts save your money on the 1131's as they did not fit dowels or bores on my 454 block for squat. I would think that the GM shims would be ok for a 396 as they just barely clear a .060 over 454. The GM shims are discontinued though.

Jeff