305 compression ratio

[377tk]

New to site,
thx for your inputs and posts
Needing estimated compression ratio on this
I’m building a flat top 305 with 601 heads with 305 head gasket shims hopefully this summer
Block is a 77 std bore no machine work done
Stock crank arp main bolts
Scat rods with arp bolts
OEM flat top pistons for a Monte Carlo ss L69
Been reading a few posts and some say I am looking at close to 11 to 1 but I think it should be closer to 10.25 to 1.
Haven’t disassembled engine or have pistons pressed on rods. So not sure how far down the piston is in the cylinder have .016 head gasket shims. Combustion chamber on heads are 53cc
Thank you

 

[axisg]

hate to be that guy but save your $$ and put it all in a better motor

 

[ck80]

hate to be that guy but save your $$ and put it all in a better motor

Was trying not to go there myself, although I do agree. I can't think of a 77 anything worth more with a 305 in it let alone as a swap.

 

[Mac442]

Any reason why you are sticking with the 305? It’s not the expensive to find a 350 block and you may kick yourself down the road for not going with the larger displacement.

 

[bracketchev1221]

I think you’re pretty close with the 10-10.25 number. Probably .020 down in the hole. This is with a 4 valve relief true flat piston. You want to aim for .040 piston to head, so .016 gasket and .020 in the hole is good.

 

[Cuse99]

Funny you bring this up. I'm trying to decide what swap I plan to do over the summer and I started researching 305 performance. Not as uncommon as I thought. The concept is that these motors are a dime a dozen and if you already have one the build can be cheap. Some of the 305 motors are making as much as 325 hp. I think the question for the OP is what are his goals and can he achieve it with a 305 cost effectively. For my application 300hp is plenty, especially for a daily driver and a huge benefit if I can use regular gas. From my research so far, the 305 can achieve 300 hp without too much fan fare. Just need a good base to start with.

Here is a sample of one of the articles I found...

305 Chevy Small-Block Engine Build - Car Craft Magazine

We rebuild a Chevy 305 small-block and upgrade a couple of bolt-ons for 325 HP. See how we do it at www.carcraft.com, the official website for Car Craft Magazine.

www.hotrod.com

 

[bracketchev1221]

I think it would be cool to try something different

 

[57 Handyman]

What each of us does with our classics are PERSONAL. Only we make the decisions on what to build! It can be as simple as doing something different and not doing what everyone else ultimately builds. One of my restoration projects was a 92 Chevy S-10 and I received countless of questions and recommendations to do a V8 swap. However, for me, a semi-mod 4.3L V6 was what I wanted, built, and installed in MY ride. Go for it!

 

[Cuse99]

I don't think it would fit in my engine compartment but I think a 250 straight 6 would be a cool build.

 

[377tk]

I think it would be cool to do something different