View Full Version : 283 compression ratio
09-08-2007, 10:06 AM
I need some advice on heads for my 283. I need to rebuild it after 83,000 miles of faithful service. Now, I know I can do a 350 cheaper and have more power, but I want to stay with the original engine.
I would like to get a little more power out of it with different heads, intake, cam and carb.
I do not know what cc head to use if I install flat top pistons. The original was 9.5:1 with the pp heads. I would like to use something less than 92 octane and still have a little performance.
I have a ZZ4 in my other car and have to run retarded timing just to keep it from pinging on 92 octane.
I have been told the 305 heads #601 are good heads, but they are still only 60cc.
There is a lot more knowledge on this sight than I have on this subject, that is what I need!!
09-25-2007, 08:27 PM
you have to buy pistons to match the heads 10.1 with 1.94 valves the 57 corvette dual 4 barrel cam is a good street cam that can run power brakes if youhave them 550 or 600 cfm carb run a after market distrubutor that can run high rpms I shifted the one I had at 7,000 and could bark 3rd with a 350th b&m trans pack and 2700 stall and 3.73s in a 82 regal make sure you up the stall if you are running an auto to around here or it will be a dog it killed alot of 5.0s its was also bored out to a 4 inch bore. Bore it out as far as you safely can and spend the most money on a good set of heads afr I recommend. 1.94 are the biggest valves you can run on stock bore alot of these blocks can be bored out to the 302! like mine was
09-28-2007, 12:37 PM
The 601 heads are more like 54-56cc. 416's are similar 305 heads, have 58cc chambers, good ports (with minor clean-up), easily support 1.94" intake valves.
I would agree to choose pistons based on cylinder head chamber volume, deck height (how far in the hole the pistons are), and head gasket compressed volume (thickness). The "quench" distance, the distance between the top of the piston edge and cylinder head, is key to preventing pinging. You should shoot for .035-.040", and obviously this is dependent upon the pin height of your pistons, the block deck height, and head gasket compressed height. Get that right first, and pick piston volume to get the right compression ratio after you measure your cylinder head chambers as-finished. You can easily live with 9.5:1 CR with proper quench height and polished chambers.
And, performance-wise, dished pistons are a better way to control CR than cylinder head volume. Also, aluminum heads allow/need about half a point higher CR than iron heads for the same power and octane requirement.
09-28-2007, 02:25 PM
If you want to use factory heads, I'd suggest the Vortec 305 heads. They are about 60 cc, have 1.84 valves, and much better ports than the other 305 heads.
09-28-2007, 04:47 PM
Or Vette aluminum heads like your ZZ4 has on it. 58cc chambers, same effective CR as 64cc iron heads.
09-29-2007, 04:07 PM
Thanks to all of you for the information! Between this info. and some of my own research, I think I am getting somewhere!!!!!!!
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