Intake Manifolds
I've just been doing some more reading and I have a question concerning intakes. I found information on edelbrock, weiand but nothing really on the offenhauser intakes, are they a good intake for low to midrange torque and all around drive ability?
Dan, doing research is good. For intake manifolds, generally the factory 4 barrel intake, the Edelbrock Performer or an equivalent dual plane competitor work well on the street.
I would spend time finding a car and planning the long block assembly. You need to research piston manufacturers to find one that makes a hypereutectic piston that with the crank at TDC will put the outer diameter of the piston crown flush or possibly 0.005" above the deck surface.
For heads the best is quench heads that have a flat part even with the gasket surface that extends over the cylinder bore. You could use the Chev LS 1.9"/1.55" valves with the beehive springs, retainers and locks. The stems are 8mm so guides need to be installed in LA heads. These valves are considerably lighter than the factory valves. Melling are fairly reasonable for price. The machine shop can cut the seats large
R and install larger exhaust seats if required, and use a bowl hog to get the bowl shape and size started. Some minor bowl porting and port match to the intake gasket size will be a big benefit. Watch David Vizard Powertec 10 porting videos, especially on the Mission Impossible project which is based on a 318. For a first build, do not worry about what is best and getting spendy on forged aftermarket rods.
On the piston discussion, try to find reasonable cost pistons machined for 1/16" compression rings. Once you get thinner the costs for 0.043", 1.5mm, 1.2mm and 1mm go up quickly. NASCAR is even using 0.7mm compression rings and gudgeon pins down to 0.787" diameter for low weight and give more room for the ring pack with long rods. Those rings are titanium nitride coated for wear resistance and low drag. Big reduction of the bank balance there. But then a NASCAR egine is $50k or more and the rod journals are sized for Honda or Toyota rod bearings.
