christianeasterby

Hi I got a 350 with the #8 heads, I got it bored .30 over and put speed pro flat tops in it. My deck is at right around 25 thou and I'm lookin for around 9.5:1 or 10. I'm assuming it's impossible but I'm putting the ferrea 2.0s and the 1.7s in the heads and I don't know if I need the heads to get milled or if I need the seats cut or what so if anyone could help it would be greatly appreciated.

rickw30

Piston CC and how far you are in the hole are just a few variables you need to know when guestimating compression.
Thickness of gasket and head CC will change compression ratio. Heads don't always need to be milled. Get your valve job completed and CC the head. Look on line and use a compression calculator for a guestimated compression ratio. Plug and play with different #'s. Not always precision accuracy but close enough for a standard street build.

christianeasterby

Thank you so much man that helps a lot!

cutlassefi

Are you using L2320’s or L2321’s?
And don’t waste your time putting 1.71 ex valves in it. 1.62’s are fine for your application.
#8 heads are typically about 80cc so you’ll need to use that as a constant.

olds 307 and 403

The few sets of #8, I measured were 77 to 78cc, just under the 79 CC spec. Follow Mark's advice on the exhaust valve. Obviously you want both bowls opened with a cutter. Positive seals aren't a bad idea either. Good luck.

Rellsad

I thank you, I can repeat step by step by just watching what you did and explained one time. This video helped me loose the fear that I could never do this but now that I know what goes on I can feel that this is easy or rather could be easy at least for me. You boost my confidence to possibly one day pursue the mechanic life so thank you for sharing not many mechanics share this idk why but you are a good man.


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