I talked to the machine shop that I'm going to have work with me on my 081 heads. I asked them to machine the seats for 1.94 int and 1.6 exh and they told me that there was no room in 305 heads for larger valves. They haven't seen the heads so I'm not sure if he's giving me a line because he doesn't want to do it or what. I'm pretty sure that I've heard of it being done before. Should I just find a different shop to do my work?

 

Yea, find another shop.
I have 1.94" intakes in my 416 heads, and left the stock 1.50" exhaust in there. But others have modded those heads with larger valves.

 

sorry to interrupt, but for the amount that it costs to have your heads cut for bigger valves, is the price actually worth it for the amount of power it gives you?

 

That's a decision that I will have to make when I find out how much it costs to put larger valves in. Right now I just want to know that it can be done.

 

I think I paid $80 to get the intakes cut for the larger valves. Then I stole the valves off some 993 heads I had lying around, so it wasn't a big expense.

 

I just read the 083 or 081 thread and that got me to thinking. How do you calculate compression ratio. I'm pretty sure that my engine has dish top pistons and I have about 8.5 to 1 right now. Will my 081 heads put me into premium gasoline land?

 

http://kb-silvolite.com/calc.php?action=comp

You'll need some actual hard numbers if you want an actual accurate compression ratio.

 

when they say piston head volume, I assume they mean the amount of dish? That's the only number that I don't have a good educated guess at and it can sway my ratio from 9.3:1 to 11:1 with the 58cc 081 heads

 

What 350 is it?
12cc is pretty normal on older ones. 7cc is normal on later ones. Look that one up.
If it's a stock shortblock, then .025" deck height.