Hey guys I am using 430 heads on my 455 for now. I got a good set of big chamber 69cc heads In great condition here. I am in the process of porting them right now. I will use a set of Stage 1 valves & spring from TA. The 455 block will be decked to 10.550 as JW recommended. Head gasket arround .40 How much should I will the heads to possibly gain some compression? Goal is a decent pump gas compression
F*** it can get hot out here. It's never gonna be a daily driver motor. Rather performance oriented Possibly with a bit of NOS
What is the compression height of the pistons you will use? Have you actually measured the chambers on those heads? I know 69cc is the published figure, but they may not be.
I would. If you know the compression height of the pistons, you can figure out how much in the hole they will be at TDC with a deck height of 10.550"
I have to get the valve job done 1st. The old valves where rusted and wouldn't display an accurate meassure. So let's change the question.. What's a avg max min head milling before there will be problems with intake fittment
My TA aluminum heads were milled .040 and I had no problem, but the stock iron heads may be different, I'm not sure. TA makes composite intake gaskets as thin as .015" which will help.
That should be no problem. For every .004" you mill heads, you lose 1cc in chamber volume. So if you mill the heads .020, you lose 5cc. That could mean 64cc chambers, but I would measure and confirm.
Just from the head milling, potentially about .5. I'm going to post this article again, http://www.empirenet.com/pkelley2/DynamicCR.html At the end of the article is a calculator you can EASILY download and install on your computer. The calculator lets you figure out static compression ratios and dynamic compression ratios. It's easy to use. You can make changes and see the results in seconds.
Those are big port castings,..have them psi checked b4 spending any time on them Wiescos sit low like .052 on the last engine I had with them Leave the port entry alone on the intake side spend your time in the bowl,..opening the chamber up around the valves .just lay that hard edge back,.and work the exhaust side good,..shorten the guide boss about 1/8in and thin it out
Not pretty but definitely worked. especially on the exhaust side. the runner had a hump on the top that i completely removed, i worked the bowls and valve guide boss. I removed casting imperfections on the runners and was smoothening everything with sandrolls, but didnt go over board since i want flow and not a nice appearance. I will drop the block and heads at the machine shop today Heads will get "leftover" parts i got "donated" Stage 1 plus springs, and 2.00/1.625 Valves possibly a milling of 0.020 to bump up the compression Block will get 4.350 bore, new cam bearings and freeze plugs + 10.550 deck
ok.. Machineshop called... the heads no good to build. Well i l take the porting as a practise run. i have a good set of 661 castings here, that i will build. unless i find a reasonable priced set of alu heads. Focus on bottom end 1st
