What compression with these gaskets?????

What about these gaskets?????

I am getting ready to install my new heads on my 455 and have a question for you all-knowing Buick lovers. I have a 1973 455 stock block. My heads are shaved .010 and are 1970 models with stage 1 valves in them. Ok, TA has the new gaskets for sale that are .027 thick. I have felpro .049 composite ones. With the heads shaved 10 and the earlier smaller cc heads with stage 1 valves what do you think my compression would be? Also, how much would I gain if I forked out the cash for the thinner gaskets? Thanks for any help you have. Glad V8 is up and running!!!!!!!!!!!!!!!!!!!!!:grin:

 

Anyone have an opinion on this??o No:

 

Bottom end is all stock. Stock dish pistons. Not decked. CC's on the heads stock except for the additional stage 1 valves. Not any chamber work done on the heads. All I need is a ballpark figure. Wanted to know if I was close to 9 to 1 or not. Thanks

 

Re: What about these gaskets?????

WIth the thicker gaskets, you will probably be around 8.3 to 8.4 to 1, with the thinner gaskets, possibly 8.8 to 1. Really hard to say without all the particulars. I have'nt done much compression calculations with low comp pistons. Jim Burek

 

I'd say you're back where you started. 8.5:1. At least you can run cheap gas :TU:

 

Thanks guys. I don't understand why it would be lower compression than it was from the factory since I have the smaller chambered heads going on it now, but I will beleive the words of the wiser. Thanks again

 

Because the actual compression of the engines were typically lower than advertized. To obtain the exact factory compression the engien would have to built to factory blue print specs, they did not come out of the factory this way, far from it.
That's why you can't just throw in a set of 10.25 to 1 pistons on a stock 455 with 70 heads and have 10.25 to 1 compression. The block would have to be decked.
When they mass produce this stuff, they have to assume that the engines will go through some rebuilds over time, with that usually comes block surfacing and head surfacing. SO if the y for instance built the engines with a correct zero deck height , after 1 or 2 rebuilds, you would have pistons sticking out of the hole. Jim Burek

 

Just to hit home Jim's point. I have a 68 430, stock re-build. .030 over. My new pistons looked identical to the stockers. I used the original small chamber heads and the fel-pro gaskets. I was sure my compression would be 10.25. I pulled the heads off, found my pistons in the hole .090-.100. That puts me right around 8.5 or so with the thicker head gaskets. That was with stock replacement 10:1 pistons. good times ou: The only way to get your compression would be to figure it out through mesauring.

 

Thanks for all the input. After getting into the engine more, I was pleased to find 1970 pistons in my 73 block!!! Little better compression than I had expected. Now, the time to finish it???