what can i do to my motor?

Question

what things can i do to my engine that will increase HP without adding a turbo or super? i have cold air intake(hood shaker) great heads, headers, a good intake a great carburator. i dont wanna swap any parts like pistons to make better compression becuz i need it low for when i want to add a SC. all thats left is port and polish? what exacally does that mean? and i heard of angling something? haha sorry but i dont know much about it

the motor is a 400 block made into a 461. all internals are great like cam.crank.rods.pistons

Answer 1

What is the motor and what type of vehicle is it in? Telling us this will help alot. You could upgrade ignition systems (MSD), get an electric fuel pump (if you don't already have one and yes this does actually increase horspower), porting and polising is expensive and will only add 1-2 Hp. You could get cams with a more aggressive grind although you would have to call somebody from like Lunati for example and tell them your plans and they will suggest the best grind for your needs.

Answer 2

Man, this is one BIG question! OK, lets start from the beginning.

Changing your cam will make the biggest difference - although you will probably want to up your compression to suit the new cam, since a larger valve overlap means less actual compression, no matter what your CR ratio happens to be - after all, valve overlap tends to be less efficient at low rpm, and at high rpm, engines tend to be less efficient at moving air into the cylinder, anyway. Also, if you want to add an SC, you'll need a different cam - usually with less overlap, since the charge will be pressurized before it reaches the valves - so expect to have to change it again. Pistons are the same - unless you want to run fairly low boost, you'll probably need lower compression pistons than stock once the SC is installed.

Port and polish: polish refers to smooth the surface of the combustion chamber so that the fuel can burn more quickly and more evenly. It also lets the gasses flow through the combustion chamber more easily. Porting means grinding the inside of the ports (in the head) and smoothing out the bend where the port turns to go past the valve stem, so that the gas can flow more quickly (however, don't polish the ports completely - you need some roughness to assist with swirl - which improves how well the fuel mixes with the air - which improves combustion and power. This is especially important with polished heads, as the combustion chamber doesn't have enough roughness or shrouding to give any real additional swirl.)

Port matching is also a good idea - it makes sure that the intake and exhaust manifold runners are the same dimensions as the ports in the head - that way, there is no added restriction as the gasses flow through the intake manifold and into the intake port, or from the exhaust port into the exhaust manifold.

Angling usually refers to either where the spark plug electrode is located inside the combustion chamber, or sometimes the angle of the valves within the head. Different locations and angles give different characteristics, but these can be pretty expensive jobs, with no guarantee of success. And if it's wrong, you get to buy a new head and start again. If there is another meaning for this term, someone else may know.

At this point, if you can't afford the SC but still want more power, I'd suggest changing the cam and re-curving the distributor (or whatever system your car uses to regulate spark timing.) Remember that if you match your ports to the manifolds, you might not be able to match them again - there might not be enough metal left where you need it. Ideally, installing the SC (and all the necessary extras, like cam, pistons, manifold, etc) would be the cheapest in the long run. This will also get you the best set-up, as all the internal parts will work together better, and the whole engine can be set up for optimum performance in one go.

Good luck!

Answer 3

GM. hae a Cast Iron Vortec Cylinder Head Assembly with 1.94 intakes, 1.500 exhausts, 64 cc chambers, straight plugs, no heat risers and will take a cam up to 4.60 lift with out machine work on the pistons.
Go to your Chevrolet dealer and for $5.00 pick up the 2007 GM Performance Parts Catalog. It's loaded with parts of intrest to you.


Great head porters are hard to find. Ask at a local composition engine builder for a name. Having seen a set of DEI. aluminum heads, intake and exhaust ports are no longer polished per say. If you has the opportunity to see them the intake ports have what looks like ball nosed Dremal tool dams machined around the circumference continuing to the bowl if the intake valves.

The four sided milled steps are continue to the intake valves with no polishing at all. The exhausts are milled with the same steps. The reason this type porting is done is to tumble and further atomize the intake charge. When it sweeps into the combustion chamber the fuel air is mixed so well it resembles a finely mixed air / fuel cloud. When the plug ignites the fuel the combustion is complete, wham, more power. When the heads are off these motors the entire pistion is clean as all the avalible gas has been burned completely.

If you could see a street motor with the heads off look closely at the pistion tops. In some areas there will be little or no carbon build up. There will be areas where the piston is clean as a whistle. Other areas are brown and other spots are black. The black areas are where incomplete combustion has taken place.

The cost of this type of porting can cost $6,000 - $8.000.
In my opinion you colld buy forged pistons and have your block decked. Check all four corners with a ringed piston with a rod connected to the crank. You'll be suprised how many thousanths difference there are in the corners of a block to the top of a pistion. It may be necessary to sweep the deck left to right more on one end than the other. The opposite may be true on the other deck. A ton of compression can be made here.

The same designed milling can be done to your intake manifold. Well mixed fuel makes more power

Answer 4

POrting and polishing is when you take the intake manifold apart and go in and enlarge the intake and exhuast ports and also polish them to make them very smooth. Larger and more smooth porting means better airflow. Better airflow means you can burn more fuel and make more power.

One more upgrade you can do, and probably should, is an upgraded ignition to make certain that you are completely burning that fuel. That will be a must for when you do install that blower.