The edelbrock heads that im planning on ordering have 170cc runners compared to most that have 180cc or 200cc. The heads are the edelbrock rpms. What benefit is the lower cc?

I think the air is supposed to travel at higher velocity. I've got the 64cc heads. It's a good street head.

Hmm, it might benefit low end torque, other than that i'd say the bigger the better. Makes it easier for the engine to breathe.

But that's just my guess.

Olli

If you are building a more mild combination or running a small displacement motor the smaller port maybe a better match. It will make more low end torque. I would say it will work well on a middle of the road 350 or motor in the 350-400 hp range. But above that I would opt for a larger 180-210cc head.

Hehehe this never ceases to amaze me. A mear 25 years ago there were no 200 CC heads out there. Back about 20 years ago a good friend of mine spun his C/ED car in excess of 10,000 RPM with 210 CC heads in a 317 in SBC... To me those heads were HUGE when compared to the 165 to 180 CC iron heads that we had previously ! Now everyone runs 200CC on the street and think they are too small in a 383 for 6500 RPM !

How times have changed !

Bill Jenkins said something once that made alot of sence about heads. He said to maintain a good allround balance of torque and HP to run the smallest runners consistant with your top end HP needs.... or to turn the same statemant around to run the largest runners consistant with your low end torque needs... either way is about the same.

One thing for sure if they are sized wrong they will hurt you somewhere.

The motor im building is a nice 350 street motor with hopefully plenty of torque. Its a 9:73 compression motor with a xe 274 cam. The edelbrock rpm heads seemed like the perfect heads for it. i just hope they are.

That should be a good combo. Should make peak power at 5200-5400 RPM. Good street motor, easy on parts if you use good valve springs.

With an engine like yours something between 160 and 180 MAX would be plenty.The 170 Edelbrocks or 180 AFR's are more than enough.... The factory Hi Perf solid lifter 340/ 360/365/375 HP 327's could be spun to 7000 useing 160 to 165 CC heads in totally stock form.... And most of these new heads are abit better than the old 1960's GM casting !