intake runner cc to cylinder volume?/ heads?

[Guest Anonymous]

hey im here to bore yall with another small displacement question again... well here goes: im wondering if their is some calculation for comparing maximum intake and i suppose exhaust runner volume to the volume of the chamber it will be filling? i know that a smaller runner is going to be more torque friendly and low rpm happy and the opposite affect with a large port. here we go. ok im looking again for a suitable head for my 283(eveyone sighs!) anyaway im pretty much stuck between three heads: the edelbrock etec 170 , the trick flow 23 degree heads and the chev double humps 462. The trickflow utilizes 195cc intake runners which seems on the larger side, which would seemingly to me produce great top end but also a soggy bottom. the e tec 170s with their 170 cc intakes might be restrictive ? whats would yall suggest ? i seem to hear only good things about vortec-style heads but the fact they were designed as a truck d doesnt really seem to fit the description of the free revving motor im looking to build.?>?>?> as usual any input is greatly appreciated. 300hp goal..250-270 ft-lbs torque.. thanks Dan

[pparaska]

Dan, being another small-displacement V8-er, I have done a bit of research on this. WIth a 283, and notably, the 3 inch stroke, too much runner volume will hurt the carb venturi signal - if you use a carb.

 

I think the E-tec 170 would be a great head for the 283, if even a bit large. It flows even better than the vortec, but the 170 cc port will NOT be restrictive under 8 or 9000 rpm . Actually, the 170 etec is a great head for a street 350 or 327. Supposedly Car Craft has an article this month on the Etec 170 and 200 heads, on a 350. It supposedly (I need to get that mag) ran better on the dyno with the 170.

 

A 195 or 200 cc head is almost too big for most 350s, from what I've read. I agree with your assessment of it giving you a soggy bottom end on a 283!

 

The 462 has 160cc intake ports. It'd be a good head for the 283 also. But the Etec 170 would be my choice between the two. Lighter, excellent flow and chamber design, plus allow a bit more compression (due to the AL and the swirl).

 

Well, that's the way I see it. But I'm willing to learn more - I look forward to more posts on this one!

[Mike C]

Just remember, with the small bore of the 283, 2.02 1.6 valves are out. You will be yards ahead if you spend the $ on the newer design heads regardless. I don't like the etecs because they have the more leak prone intake design of the Vortec heads with its fewer bolts. Chevy high performance mag tested all of the iron eagle heads, 165, 180, 200, 215 and 230 cc. The 215 just lost out to the 165 for average torque below 4000, beating the 180 and 165. Their conclusion (and this has been my opinion for a long time) is that the cam has more to do with killing the low speed throttle response than the intake port volume did, because when you combine the large ports and a huge cam, of course low speed throttle response is killed, especially with 8.5:1 compression. Best bang for the buck for a small bore motor is the Dart SR torquer 305. The 4" bore and the ability to run the larger valve heads is worth a bunch. That's why a built 327 makes more than 15% more power than a compareable 283 even though it's only 15% bigger. A 302 is the best small displacement chevy hp/ci, but pistons will put you in the poor house. 350 with Northern Auto Parts high perf rebuild kit ($415 with forged pistons and Crane Energizer cam, this is a smokin' deal)and the Performer RPM heads makes for a super stout, reliable street motor. They will substitute any of the Energizer grinds at no extra cost. This will be cheaper than building the 283 even if you have to shell out another $150 for a core. Besides, the 3/8 bolt rods are much stronger.