Why Does In Work On The Brand X Engines But Not The 318?
It does work and better than the brand F or C heads.
Let me ask you 1 question or so.
What is your plan?
How fast do you want to go?
Why did it take you this long to answer on piston height.
Generally speaking, when a question is asked here, if theres not enuff info giving to begin with, we, the responders to the question error on the side of caution and generally speaking offer advice on a more street orianted performance build up rather than a hot street or race type build.
If your not coming foward with details and what you want/expect out of this engine, then all the info your getting doesn't properly apply.
Enter the wrong numbers into the computer, you get a wrong answer.
We are no different. Come forth with some answers so you can get better advice and proper advice for the direction your going in.
This way, you'll achieve your goal the first time out instead of the second or 3rd time. Unless you don't mind spending lots-o-money.
(1) Will I Lose Combustion Efficenty With The Change To Aluminum.
Yes, aluminum has a higher heat transfer rate than iron.
(2) How Will The Heat Loss With Aluminum Effect Performance.
It will act similar to being down 1 point of compresion.
(3)will The Compression Ratio Drop Useingthese Heads With The Stock Flat Tops.
Best way to know is to know your engine. Starting with the exact amount of cc's the head has, gasket to be used vs. the stock one, how far down the hole the pistons are now, overbore if any, so really that's bore and also stroke.
There are on line ratio calc's that should be looked into.
(4) You Say That These Heads Work Well For The 318,340 And The 360, But Are The Ports To Big For The 318.
That actually depends on there intended useage. What are you planning?
(5) Are These Heads To Much Flow.
It's more of a port volume issue rather than how much they flow.
(6) Are The 202 Valves To Big To Keep Good Velocity At Lower Rpms, And Will Gears Like 410s Help Solve That Problem.
In short;
Yes & yes.
(7) Will I Need To Ru N Higher Compression Pistons With These Heads.
Again, this is build dependent. Givin the fact of your running a zero deck piston now, that will give a good quench area with a .039 gasket, your ratio should be very good for most applications from a basic grocery getter to a mild strip car.
The way I calc up the deal;
Standard bore 318. 63 cc head chamber and then add 5 cc's for valve reliefs, .039 thick/4.00 bore gasket will equal a 9.55-1 ratio. It'll be 9.71-1 @ a .030 overbore. 9.84-1 @ .060 overbore.