r.barn

Just wanted to make sure I understand this right.

If the same cylinder head is offered in 64cc and 58cc combustion chambers.
the 58cc head will make more power cause it will have a higher
compression ratio right?

So I would want the 58cc to maximize power from that head?

JeffUtica

Yup.

Dath

The smaller combustion chamber will increase compression. One of the reasons people go with the larger cc's is to purposefully lower compression and then bolt on a power adder.

I'm going with 64cc x303 heads for that reason.

WLingle92lx

You are going to gain ALOT of compression and power going from the stock 64cc chambers to 58cc chambers.

Ex: The pistons I'm running are 12.9.1 with 54cc chambers. I'm running 60cc heads so the compression is dropped way down to 11.2.1 according to Jeg's.

Thats 1.7 compression points loss from 6cc's. You are looking at going from 9.0.1 with stock 64cc heads, to 10.7.1 with 58cc heads.

Sombody Correct Me If I'm Wrong?

FullAuto

There is more to choosing it than just looking for that extra little compression for a few more hp. Piston selection and chamber design often comes into consideration when choosing the head. For example, the AFRs have a different design between their 58cc chambers and 61cc chambers. The 58cc is widely accepted as the better design and will buy that even if they are going boosted and choose a piston to reach their desired compression ratio.

Jared_blown5.0

wlingle your about spot on with that... I have 58cc head and that combustion chamber with my je pistons is 12.2:1 cr, and with a 64cc head it is 11.0:1

luckythirteen13

afr told me that their 58cc heads will get you about 9.6:1 cr. cant be much more because i run 10psi on those heads