[68c10owner]

When you decide to build a engine you have to match everything. You need to decide what size engine your going to use first. Then what are you going to use it for? What RPM do you want to spin it to? Then you start planning out what parts your going to use.

Cylinder heads-you need to know what heads your going to use on the engine. This will match the use of the engine. If your building a street engine or even street /strip your going to want the smallest runner that gives the most air flow and velosity. Cross section area of the port is important as well. Valve size is important. If you have a big CID engine like over 500" then you might be able to get away with a small square port head but best to go on the smalelr side. For high RPMs then the square ports will work fine but dont usually mix so well on street motors but there are always exceptions to the rule.

Camshafts-Do you want hydraulic? Solid? Flat tapper or roller? Roller cams will make more power and wont require as radical of a camshaft to make the same power of a flat tappet because the lobe profiles are more aggressive. There is too much to get into with cam profiles but lobe intensity,lobe profile and lobe sepereation all play a part. Some engines will make better power with a single pattern cam, some will need a split pattern. It depends on the cylinder heads used. Some have weak exhaust ports like OEM BBC heads and some are very strong like the AFR heads. You cant pick a camshaft without knowing the size of the engine, what RPM and what heads are being used.

Compression-More compression is more power. Tighter you can squeeze the charge the more power it will make. Problem is you can only run so much compression on pump gas before you get detonation. Cylinder head material (iron or aluminum) will have effect on this as well as camshaft over lap. Aluminum heads will usually allow up to 1 full point of compression over iron heads because of heat dissipation.

Intake manifolds-You have 2 styles typically. Single plane which are open and dual plane with individual runners. Single plane intakes usually work best in high RPM or all out race engines and dual plane intakes generally produce better low to mid range torque and throttle response. Again there are exceptions to this rule. Generally you want to match the RPM of the intake with the RPM of the engine.

Headers-smaller tubes will give better low-mid range and throttle response. Big tubes have less back pressure and usually produce the best HP numbers. There is a formula to figure out what size header will work based on engine size and RPM. For street cars its best to go on the smaller size.

It`s not just about bolting parts together, its about planning your combination. Everything comes into play which is why its important to be 100% honest with your builder.

Intake manifold style and headers size play a part in the over all HP and torque numbers of the engine but the camshaft and cylinder heads play a bigger part than anything else.

This is all I can offer the OP. Good luck with your build.