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There is a dork flowed a C8 and a C4 and got 213 and 231#.500 intake

October 3 2017 at 6:13 AM
Bill Ballinger  (Login 65billgal)

Then he flowed the exhaust and got 181 on the C8(WTF) and 158 on the C4. This is on U-tube BTW. He doesn't have a chunk of intake attached to the intake, and my C4s stock were 175 just washing them out. So he is recommending a stock
C8AE head for a 445 stroker he is going to put in a truck. My issues

1. He called them low and MR heads and even remotely screwed that up.
2 No valve jobs listed, who knows what they had.
3.In a mild engine, in fact even not so mile engine the Exhaust to intake ratio does not mean that much Exhaust just wants out. A 460 that flows 300 at .500 and 140 at .500 will blow the 445 he is building off of the road. Exhaust that is at least 66% of the intake is good enough to have no to little effect on power.
4 You have heard the Mr Shitface being praised the original designer of the internal combustion engine.

Barry responded, and as we all know, you can make either one work, but why not just buys some Edelbrocks and have a competent machinist put them together, no muss, fuss, or just have a good valve job and some decent valves in the C4s and find out that they can make 480 hp. The C8s at 213 cfm ? are you joking? The C4s stock at 231 just with a valve job and work on the pinch to get it to really flow 231 can make 400+ on either

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Bill Ballinger
(Login 65billgal)

BTW, why I know this, is first my C4s, but I built a 460 for a guy

October 3 2017, 6:37 AM 

Mildish cam, 2.19 intakes in D0VE heads with flat-tops and 1.65 intakes. He ran it in a '68 Cougar. The intakes flowed 302 at .550 and the exhausts did a measly 148. The engine dynoed at 500/500 and would melt the tires to the rims.

My FE C4AEs at 12 degree angle cut with the widened ports and work that had been masterfully done on the port pinch, flow 274@.525 with 2.055s and 185@.525 with 1.58s. The angle cut and a chunk uf worked intake with the same pinch as I had quieted way down, BTW. It dynoed 452 and 488 out 394 ci. Thats not "hero" territory, but it is the sweetest sounding thing you ever heard.

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Tom P
(Login tomposthuma)


October 3 2017, 10:25 AM 

I have had dozens of C4AE-G heads and it seems rare to find two with exhaust ports alike, some seem to be cast with more lumps along the outer wall. Perhaps core shift.

I would think the guys running those in SuperStock before porting was allowed probably had to go through a bunch of heads to find the best ones.

The C8's at least seem to be consistent.

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Bill Ballinger
(Login 65billgal)

I am lucky I guess, i have three sets of C4s that are almost perfect

October 3 2017, 4:33 PM 

I just did a little bit of work on mine really just jot the oily crap out and they did 185 with 1.58's. I have a theory on C4s too, they were non emissions and most didn't even have PCV. The C8s ran as hot as a two peckered Billy Goat, so Ii bet that is the reason more than the unibody cars to keep them from warping and sooting up, plus corrosion from Tetra gas. My three sets are 64 castings. all are very clean. I have just put them on in place of C8s and really picked up a considerable kick in the pants.

For the most part, unless its down to 3-5 hp, exhaust just wants out, good headers and non restrictive exhaust really works.

This message has been edited by 65billgal on Oct 3, 2017 4:35 PM

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(Login Ranchopower)

air flow

October 6 2017, 3:37 PM 

Would be nice to have actual flow charts on both style heads

so you can see the flow difference in the lower opening rates

the C8s may flow better at lower lift rates than the C4s

The C4 exhaust port at the end has a lip on the wall that would disrupt flow.

the C8 has no lip and smooth wall just like the med riser head.

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