Block decision 1.9L higher CR vs 2.0L lower CR

[all-mtr-teg]

My buddy is at a crossroad with his build's block options.
He's got a GSR head, all new Supertech springs, valves and k-series retainers, keepers, S2S2 cams, S2 IM, JDM ITR header.
We've got access to 2 blocks.
Block 1
B20, 84.5mm bore, with Manley rods and 11:1 Arias pistons. Originally built for spray.

Block 2
GSR block, 82mm bore, OEM LS crank and rods, ARP bolts, NPR PR3 pistons, fully balanced rotating assembly.

We were debating about which block would be best for an all motor setup.
I am leaning towards Block 2.
Pros
Higher CR (about 11.8:1 vs. 11:1)
Main girdle
No vtec conversion required
Cons
Less displacement (almost 1.9L vs. 2.0L)

According to the zealautowerks estimator, block 2 is about 1880cc. Will the
B20's 2.0L makeup what it lacks in CR with the added displacement?
This is gonna go into a daily driver with heavy weekend abuse (drag).
If it were up to me, I would rebuild the B20 with higher CR pistons, but he is on a limited budget and I'm practically getting either one of these blocks for him as a trade for some work I did for the shop that has these blocks.

[patriot]

Budget? Block B.
Me? Block A
...but also if the head is stock, you wont see much gain in the extra 120cc's.

[all-mtr-teg]

Originally Posted by patriot

Budget? Block B.
Me? Block A
...but also if the head is stock, you wont see much gain in the extra 120cc's.

That's what I was thinking, Block 2 has same stroke as block 1, but about 120-130cc less, but almost a full point higher CR. The S2S2 would benefit more from the CR bump than the displacement bump right?

[patriot]

Cam size really depends more on displacement but being in the 11-12:1 compression area I would imagine they would make very similar numbers with the B20 having a little more low end grunt...
The GSR block would be easiest plus without worry of sleeve issues.

[00Red_SiR]

you could always run a thinner head gasket, like 1 layer and jump up to at least 11.5:1 on the B20. The advantage of the larger bore is unshrouding the valves so it can breath better. It also has the potential to make more power with every mod.

[mar778c]

I would run block A. 11.1:1 is plenty of compression for most shelf cams.

[all-mtr-teg]

Originally Posted by 00Red_SiR

you could always run a thinner head gasket, like 1 layer and jump up to at least 11.5:1 on the B20. The advantage of the larger bore is unshrouding the valves so it can breath better. It also has the potential to make more power with every mod.

Very good points, I completely forgot about the possibility of a thinner HG. The valves are already deshrouded a bit, but you're right about being able to deshroud them more with the 84.5mm bore.

[all-mtr-teg]

Originally Posted by mar778c

I would run block A. 11.1:1 is plenty of compression for most shelf cams.

I had a talk with a local tuner about the 2 blocks, he was recommending Block B. He said something about how cast pistons are able to run a tighter piston to wall clearance = longer engine life and better ring seal which will make more power. I was under the impression forged internals can last just as long as cast and that ring seal were dependent on ring design and cylinder wall conditions, not so much the P2W specs.
He also said something about how s2s2 and the pro1 cams do well at
11:1 CR but will make another 5-10hp on the same all motor build if it had 12:1 CR, so that would almost compensate for the lower displacement, w/o the headache of B20/vtec leaks, etc.
But I still like the added strength the B20 block has to offer with the forged internals.
Damn this is a tougher decision than I originally thought, and now my buddy keeps changing his mind as to which route he wants to go.