[tached93gt]

There's a 93 coupe running 6's in the 1/8th mi running a 306 with AFR 205s, I will see if I can get more info on the car, he runs at one of the local tracks...

 

[Badboss351]

Yes, you can have "too big" a head, but it depends on the combination. A 200cc runner, on a lightweight, nicely geared, manual car(or loose conv. auto), and the right cam specs will run. We had a stock bottomend with Canfield 200cc+ runner, victor jr intake, Holley 750, C4, 4,000 convertor, 3.73's, it ran 7.6's @ 94 mph, and 6.4's @ 108 with a 200hp shot. The car had no transbrake, and was far from optimum. How's this for a "real world" big head combo???? Then again, I had a car with ported 69' W's heads, stock bottomend, 3.73's, T5, everyday car. He ran 8.0's @ 91 mph NA. You will find many combinations that work, its just putting together one with what you have/want.

 

[nosmatt]

thanks chuck, that thing runs hard, congrats!
i assume the 2800 stall in the post was a misprint, as your sig states 3800....sounds about right now

i am knee deep in aod building right now.... but i have my other engine torn down, and trying to decide which way to go...... got the money for the heads sittin in a drawer at home, i can buy any set i want really....just want to make the best choice for me. this trans is kinda my practice trans, then next is a 4r gutted aod, or a 4r with a stand alone controller, or manual vb that i will also build..... and a high stall converter dont skeer me...especially with od and lockup.

as for your thoughts about stalling air column, thats pretty much why i started the post, try and cut through some of the misconceptions (both regulars, AND my own)...... and i like to be a little different, but also dont wanna be stoopid.... if an ed combo runs ~ 2500 for a top end that works, and it will cost me 3500 to do it "my way"......well duh. i am not poor, but not well off enough to blow a grand for no reason.


still really do not have the answers i wanted, but alot of good input! this was going to take another twist, assuming i got the info i was expecting to hear....but have not. the large head, small cam, high rpm screamer, that was not a TURD down low........add an s trim, or t trim pullied for a street freindly 12lbs.....and of course, another custom cam. im out 300 for a cam, and could likely sell the other one to someone else..... this saves selling heads, and cam down the road.

the wife is not affraid of me spending ONCE to get the parts i want, but in the past, it has become the norm to buy a ****load of parts, only to sell em later and buy other stuff..... eec tuner to dfi.........then back to eec tuner....n/a to strim, then back to n/a...... forged 331 for turbo, then to a 347 n/a, then a 347 blown....then back to a high winding 306......it gets old, and i can see her frustration


anyhoo, btt!!!!!!!

ohh, and tached 93, i would be very interested.

 

[2wld4u]

hmm, well I can attribute to the big head small cam thing, a 72 chevelle, 355 cid, 9.5:1 3200 stall, 4.10 rear gear, PTL 230cc heads, cast iron (out of the box), victor JR standard height intake, 800 Holley DP, I thought the heads were just overkill on this application, with a mild single pattern Solid roller I stalled it to 2200 on the footbrake and pulled the driverside wheel, so yeah, id say it had plenty of bottom end, Im not sure what it runs, I dont think its ever been to the track, fun to drive though, this was a case of the parts were there and we used them... so I think there is something to the big head small cam theory,

I would rather build a stout 302 with the AFR 185cc heads if I had a choice and I was going to use AFR heads, these heads will pull from top to bottom, and everywhere in between..

I also believe this head will allow you room to grow, add a more agressive cam, better induction and exhaust, MORE POWER... and this head with a power adder? lol...


A 200cc head might be a lil much, unless your going to turn the rpm up a lil then you'll see an advantage, along with more gear/stall etc..

the AFR 205 head imo, is suited well for a higher RPM 351W, or a lower rpm 393,408,

the 225cc head would work well with a 393,408 and higher RPM..

pretty simple way to look at it, and with this, you shouldnt go to far off base with your build... no matter what anyone says...


2wld4u

 

[short throw]

OK, I went through this thread and realized that I may have a fairly strong combination. I was flamed last month when I asked for thoughts on the combo. Would this fit the big head small cam theory?

306 roller
Wolverine 1087
10 to 1 CR
Roush 200's as cast
1 3/4 LT's to 3" Prochamber
Torker intake with 650DP
MSD 6AL

 

[Jay Allen]

306 roller
Wolverine 1087
10 to 1 CR
Roush 200's as cast
1 3/4 LT's to 3" Prochamber
Torker intake with 650DP
MSD 6AL

The tq'er manifold is a tad outdated. You'll find that a Weiand Stealth would be a much better choice for that combination. Should run real nice. A middle 11 sec combo.

I guess this was skipped over or ignored. I agree we do not race dynos. I agree that theory is just that. But PROOF cannot be over looked.

In 1991 I had a 100% stock block. I flycut the pistons in the block with a dremel in the driveway. I used TFS Street Heats that were 205cc (2.02 X 1.60). At 600" lift they went 305/210 cfm. I used a Wolverine WG 1087 with 1.7's. 222/232 542/567 w/1.7's 112 LSA with a 107 IC. I had 10:1 compression. 1 3/4 Motorsport J-302 Headers. 3" exhaust. A TFS Truck intake that utilized dual 54mm TB's off of a 460 EFI truck. The first Pro-M EVER made and it was 24# injectors. A FMS 110lph pump (the biggest that there was). A stock T5. 100% stock suspension plus Lakewood slapper bars. 4.10 gears. 26 X 10 slicks. Nothing, absolutely NOTHING by todays terms. The car weighed 3280 with me in it. It was the ONLY car my wife and I owned. Thus, we drive it EVERYWHERE! AC, PS, PW, CD player, it was all there. I went 11.471 at 117.1! By the math that is over 400 RWHP! Guess where I shifted and it went the quickest? 5800 RPM and it crossed at 6300 RPM. I had a computer (Crane Interceptor prototype that was given to me by Doug & Mike Wallace) that allowed me to shift higher. I did. I shifted at 7000 RPM because I could. I went 12.30's right off the bat after I had went 11.60's with a stock computer. Thus, I began to short shift. The faster and faster I went as I short shifted. I ended up at 5800 RPM. Now I do not feel that the WG1087 was even near optimum, but back then there was only 3 cams available and *custom* was a Taboo word. The same combination today would be very close to a 10 sec timeslip because of the parts available.
205cc S/H's at 5800 RPM with a 3" stroke at 5800 RPM. Go figure.......

So who has 205cc heads and RACED it? There is one example that was raced on a track.

Daily driver that my WIFE drove.
At 3280lbs (by the math)(more theory) that is:
11.471 @ 3280 = 429.5 RWHP
117.1 mph @ 3280 = 407.2 RWHP

In the *Stock Cam* thread I posted that I went 11.60's and 11.70's with the same car & JUNK but I used cast iron TFS Street Heats, a GT-40 manifold and a stock camshaft with 1.72's.

My 289 (292) just a couple of summers ago went 10.80's at about 3100lbs. That was with Canfield heads cleaned up. Yes, this was carbureted and that is a huge advantage. Yes I shifted that at 7000 RPM (+) and that combination was NOT for the faint of heart. But never the less with PUMP gas, Mufflers, 200cc heads on a 2.87 stroke, it went 10.80's.

So, if running middle 11's (11.400-11.699)(Or quicker) is easy at FULL WEIGHT (3200+lbs) and is done routinely at 302 cid (Ah what the hell, 306cid), list those combinations here. I'd be interested to see what heads are on them.

 

[Ed Curtis]

The objective of my combo is to keep velocity up and to get it moving early int the RPM band. On the dyno my 306 makes 300+ RWTQ from 2800-5100 and peaks at 346 RWTQ with the converter locked through an AOD. HP drops off after 5500. Last winter with a 5600 pill in the shift light the car ran a 11.41 @ 116 on motor.

When I daily drove the car, it would get lugged at 1200 RPM in 3rd or 4th gear and never buck. I figure most OST cams are designed for 5 speed cars that can lauch off the rev limiter or be manually held in a lower gear to keep the revs up if need be. Which is why I went with one of Ed's cams.

So who has 205cc heads and RACED it? There is one example that was raced on a track.

Daily driver that my WIFE drove.
At 3280lbs (by the math)(more theory) that is:
11.471 @ 3280 = 429.5 RWHP
117.1 mph @ 3280 = 407.2 RWHP

Math?

Hmmmm...... :shakehead

Ed

 

[TrackDaze]

Some would do well to take a look at the Corvette LS6 and LS7 (C6 Z06). The LS7 uses huge flowing heads (300+ cfm) with a little bitty camshaft to make lots of power across the rev range and pass smog.

Is there potential for more power? Sure. Could you make the same power with high revs and less expensive heads? Probably.

However, having a docile, smooth idling thumper that will smog appeals to many of us who live in states with emissions testing...

 

[nosmatt]

LOL!

agreed on the ls1's.......
what is the port volumn of these heads, in stock form...???????

big flow does not mean big heads............ but, i believe comparitivly they are not quite the same as a ~200cc head on a 300" motor..... but i could be wrong...

 

[Ed Curtis]

LS-6 Stock Flow Numbers
206 cc intake runners

Lift In Ex
.100 62 59
.150 94 86
.200 126 108
.250 156 128
.300 184 143
.350 206 154
.400 224 163
.450 239 170
.500 251 176
.550 256 180
.600 257 183

Feeding 346 cubes too!
Not as big as you thought huh!

It's a relative to what works versus "theories"...

BTW... LS7 is 427 cubes.
It needs a bigger head to feed itself properly.

Ed

 

[nosmatt]

damn, that was a bit on the harsh side ed..... skip that second pot o coffee tomorrow!

sure hope your not takin anyhting personally, i have in no way attacked ya! think i even said something along these lines..............

but, i believe comparitivly they are not quite the same as a ~200cc head on a 300" motor..... but i could be wrong...

anyhoo, your opinions very welcome, and appreciated.

 

[Ed Curtis]

damn, that was a bit on the harsh side ed.

Nothing harsh in the truth Matt...

Unless you can't "handle" the truth...

Ed

 

[nosmatt]

I prefer to handle BOOBIES, but the truth might have to do.....


do you disagree that this setup can work, and work well???? or would you rather not get into that???

 

[TrackDaze]

Wouldn't the lower-rpm operating range of a small camshaft make up for some of the lower rpm torque lost due to having larger intake ports and lower port velocity?

Up top, is it better to have the power curve fall off because the ports are running out of air flow capacity (sharp falloff) or because the camshaft is optimized for 5000rpm instead of 5800rpm (gradual falloff?)?

CompCams has an article where they put a 224/230 cam in a 408 with Edelbrock Victor Jr. heads. The author says the engine is being used to tow boats. The engine peaked at 5500rpm, but made 88% of its peak torque at just 2000rpm.

What's happening there? Is that cam relatively small for a 408? Are those heads relatively big for a 5500rpm power peak 408? Or is a 408 just so big that Victor Jr's are like GT40Ps on a 302?

Comp Cams Article

 

[Jay Allen]

Ed those are impressive LS-1 numbers. Sounds like a 12 second car. Imagine that! 206cc LS-6 head (5.5" long port) is the same as a 178cc TW head. The same as a 187cc AFR head. The same as a 197cc Canfield. Hmm.......I thought Canfields were *Too Big*? Plus the LS-6 has a much better TB.. A much shorter intake manifold runner. A teeny tiny bore. Oh ya, what are the ZO-6 camshaft specs? Right from the *GM Performance* catolog:

204/218 at .050
With factory 1.7 rockers 553/550
117.5 LSA
120IC/115 EC

Small duration (with BIG split BTW ); Tall lift; Wide LSA; Pass emmissions; Idles smooth. Those idiots at GM! Why would they want and go and do that??? So let me get this straight. A short duration/tall lift cam with big split. A decent head by Ford standards, ie *Too Big*, and the cars are friggin' fast. Hmmm.......Isn't that what you are arguing against?

You want to be irrelevant. So will I. How about the DOHC Cobra? Seeings how everytime I bring it up YOU side step it. 281cid. 300cfm heads. Same *Port Volume* as a 200cc Canfield (TFS S/H or Z304). Passes emmissions. Idles baby smooth. Lots of power everywhere. Guess that engine is theoretical as well huh? Guess the Ford engineers are wrong too. Let's do this. We'll take a 4V. Make the heads smaller and flow less. We'll then put a larger cam in it. Wait......Hang on.......OMG, it'll be a 2V then! I'm SURE a 2V will outrun a 4V right?

Airflow = Power. The MORE air you can process through -ANY- engine the MORE power you'll make. How in the hell is a 165cc head that moves 250cfm going to out perform a 200cc 300cfm head? What is *CFM*? Cubic Feet per Minute. per Minute is unit time. You are left with *Cubic Feet* Funny, I thought that *Cubic Feet* was a VOLUME measurement. Thus:

Volume of air/Given Unit Of Time. Sorry, no theory there.......

Forget the smoke screen. Where are the middle 11 second, 165cc heads, 3200+ lbs cars? I have done it twice with "Too Big" of heads over 13 years ago with friggin' JUNK! One of them with a *stock* camshaft & iron boat anchor heads! Show me one, please.

No friggin theories. More proof.

Here is ANOTHER one. No theory, he has video. Trent Thompson. 306, Systemax, Canfields (Stage I Plus from Fox Lake), one of the Anderson cams. At full weight he went 11.40's.

Tell ya what, I'll get a few of the guys who have the wrong heads to come in here with REAL WORLD examples. I am sick & tired of your "Theory" words. There is no theory. There is proof. It is YOUR smoke screen to hide the obvious.

Ya know, Columbus had a theory as well. Think about that *Theory* too.

 

[Jay Allen]

Wouldn't the lower-rpm operating range of a small camshaft make up for some of the lower rpm torque lost due to having larger intake ports and lower port velocity?

Yes. Simple concept.

 

[N8Miller]

Guys,
while i am not totally up on this thread, all i can say is that Jay Allen really knows what he is talking about. he made a cam that is "smaller" than my comp cams xe274, but runs SO much better with my "bigger" vic jr head setup.
when i saw the specs, i was a bit worried how the car would perform, but now that rick got it together and the MAF is rebuilt, the car runs AMAZING!

thanks again, Jay

 

[FastDriver]

Forget the smoke screen. Where are the middle 11 second, 165cc heads, 3200+ lbs cars?

Is that a joke?

Anyway, does the intended powerband of the motor make a difference as to which head you choose? i.e. wouldn't higher revving motors require bigger heads to perform in their powerbands? Just asking.

I'd still like to see someone with an AFR205cc 302W running a small cam. No offense intended, but preferably that person will not be from Jay Allen, or Ed C. but rather from someone aloof from the argument.

Thanks,

Chris

 

[FastDriver]

Guys,
while i am not totally up on this thread, all i can say is that Jay Allen really knows what he is talking about. he made a cam that is "smaller" than my comp cams xe274, but runs SO much better with my "bigger" vic jr head setup.
when i saw the specs, i was a bit worried how the car would perform, but now that rick got it together and the MAF is rebuilt, the car runs AMAZING!

thanks again, Jay

I'd really like to know how it runs. Take it to the track or if you already have, post the times, please.

Chris

 

[damage]

You want to be irrelevant. So will I. How about the DOHC Cobra? Seeings how everytime I bring it up YOU side step it. 281cid. 300cfm heads. Same *Port Volume* as a 200cc Canfield (TFS S/H or Z304). Passes emmissions. Idles baby smooth. Lots of power everywhere. Guess that engine is theoretical as well huh? Guess the Ford engineers are wrong too. Let's do this.

I can take a stock headed 302, port it only (no valves), use a medium duration cam (say 218/224), put a nice intake and exhaust system on it and make the same power. I know cause I've done it. Putting another motor just like it for my brother.

I guess you forgot about the butterfly valves too....

I think you also forgot about the 3V heads making the same power with substantially less flow. Granted they have VVT...but talking pure horsepower numbers.