Or another way to look at,..look at the heads used on BB 396's and 402's. Oval-port heads (much smaller than square ports) had 250cc intake ports. These engines didn't have any "velocity" issues. Even peanut port heads, literally used on 396 dump trucks, are bigger than the 180's.

Here's some great info:

http://chevyhiperformance.com/techarticles/41598/

Again, big cam w/ small heads is recipe for major diappointment.

Good luck!

 

Hi Ed,

I'll share my $.02 with you based on my 406 build.

I'm running a .510 lift cam and wish I went bigger. Mid .5s would be perfect for a weekend cruiser and the occasional award-winning burnout.

I went with 190 heads because the flow ratings were not that much different below 5000rpms. I think 200 would be fine and 220 a good choice also for intake runner cc's.

Low end torque is ~not~ going to be an issue for you. I would gladly trade some lowend TQs for high end HPs these days.

 

That is where a little wider LSA will help. In the larger duration cams the valve overlap, the point where the intake and exhaust is both open will bleed off some compression. Less valve overlap with a little wider LSA will help keep your dynamic compression where you want it with a larger duration cam. It's all a balancing act. You are going in the right direction getting all the input you can to make your decision. A street engine is what you are building. Seems like some of the advice you have recieved might be more geared toward a drag race engine which is not your objective. The heads you have will work fine with the right cam. With a 3:08 gear and wanting streetability the heads you have seem like a good option to me if they flow that close to an AFR 195. They will provide gobs of low end and midrange torque and if it will never see 6000 RPM I think the $1000 would be better spent elsewhere. A 3:08 with a 4 speed and 220 heads doesn't seem like a real streetable combo, it will fall on it's face taking off from a stop sign and in town stop and go traffic. You can't compare the stock heads with the new aluminum designs. FLOW is what you want. The 180 heads you have probably flow as much as the old big block oval ports. Good flow #s and a smaller port will give you good intake velocity to keep your fuel atomized and torque where you want it, 5500 and below. The LT1 and fuelly heads from the late 60's and early 70's had 165 cc intakes and lousy flow compared to the newer design heads and they pulled almost 400 HP out of a 350 with no roller cam. JMHO.....By the way, I got a rebuilt 3:55 rear end that would wake that new motor up.

 

AH HA...the light bulb just went on.
Eddie

 

Great info...thanks. It's much more in depth than the AFR catalog I have...but basically says the same thing AFR does for cylinder head selection.
Eddie

 

EXACTLY my thought as well. Looking at numerous charts tonight, the 200cc flow really takes off after 5k (200cc and up) and beats the 180cc-190cc hands down. If my motor doesn't live in that upper RPM neighborhood....why spend $1200 or more for new heads? More research and bank account shifting is the chore for now...
Eddie

 

Revised last post. Also, the duration numbers at .50 are a little misleading on the roller cams compared to the regular hydraulics because the ramp rates are quicker. You can go with a larger duration cam with hydraulic roller than regular hydraulic. Compare the duration numbers at initial lift on both and you will see what I am babbling about. A TKO 600 with the lower 1st gear or a lower gear rear end ratio would help with the stop and go and taking off from a stop sign situation.

 

You are forgetting it is a 406ci not a 350ci, all the theory in the world means nothing until you tryit in the real world. I have been driving around for 2 years with a 219cc race heads, a huge solid roller cam, a single plane intake, a big race carb and a 3.08 rear end. I tool around town in 4th @1500 RPM. I have over 450ft/lbs at 2000 RPM does that sound like it would have any trouble getting the car rolling ?

Just because a cam can rev to 7000RPM doesn't mean you are going to be driving around in the 5000RPM range. Like I said above mine runs fine at 1500 RPM and I do most of my drving between 1500 - 2500 RPM but the potential to rev it to 6500 RPM and rip up the pavement is there all the time.

There are many misconceptions here in this thread and on this forum about big inch small blocks. They are alot closer to big blocks than small block and behave that way.

Go with a bigger cam and don't worry about the bottom end, you will have so much torque from 406 that it doesn't matter what cam you put in there within reason. And in the future you won't have to change it when you can afford bigger heads, because believe me that it what you will eventually do

 

I just checked out your video. AWESOME sounding motor!

 

Hi Eddie www.ryanscarpage.50megs.com/combos1.html Check this site out. These are STREET engines only. Combo #17 is me with the tripower + nitrous Check out combo #71 383 with 525 HP and 535 FT. Lbs with 190 AFR heads and 9.4 to 1 comp. Cam is big lift to compliment the head porting. You can pull pretty big #s with the smaller intake runner heads if your components are properly matched. I think your 475 HP is easily done with them.

 

Have you got that built already ? Are you going to run it on a dyno ? Very nice combination

 

Is in the machine shop now. Hava all the components. My Machiniist builds a lot of big block truck pull engines and has been really busy. It should be done in about a month. It will be tuned on his dyno as the large base tripower, nitrous combo will be a pain to dial in. Anxiously waiting to post info when done. Lets help Eddie get his 406 to where he wants it. I thought some of the info in the site I sent him will help him make an informed decision on cam choice for his. this is the old 327 setup.

 

Looked at combo 71 why did they take a 190 runner head on a 383
and port it?? do they have any 406s to look at. a 180 runner stock
head on a 406 will make a good pickup motor.

 

He is going with those heads until he can afford bigger that's all there is to it. A 406ci requires big heads because it pumps more air, there is no getting away from that, anything smaller that 210cc is going to hurt performance, but will be OK on the street.

There are two 406ci motors on that engine combo site and one uses Edelbrock Victor Jr. CNC heads which flow even more than mine at 300CFM+ and would be over 220cc intake runner and the other uses Air Flow Research 210 heads which flow in the 290CFM range

 

motorhead ok I will leave it alone probably said to much anyway. I
just hate to see a good motor gone bad.

 

The heads Eddie has he says will flow right at what a 195 AFR head flows. That is WAY better than a stock 180 runner head and actually is better than a lot of other manufacturers 200 or larger cc runners. I think with properly matched components they will be fine up to 5500 RPM or so. Granted they are not big enough to pull huge HP numbers at higher RPM. That is where they will be weak. But if you look at what he wants which is a streetable combo, the supporting drivetrain which is a 4 speed and 3:08 rear, his statement that the motor will never see 6000 rpm and he is going hydraulic roller which drops of at around 6000 RPM anyway the heads will be fine. Sure he could get more power out of a bigger runner but this is what he has to work with now and the difference at the 1000 to 5000 RPM range is probably negligable especially with the increased port velocity to help with efficiency. You have to remember there is always someone faster. and you can always build it bigger but we all have different budgets and priorities. A stumpuller type engine is not all bad with a 3:08 4 speed

 

I've always wanted a gold plated toilet, just isn't in the cards right now

 

Hope this comes out AS TYPED!!!!

Protopline 180cc (Cast Alum) 2002 CATALOG
Intake Valve Test Data @28" of water
.200----.300----.400-----.500----.600----.700
150.89--206.86--242.68--257.90--263.27--270.12

Airflow Research 195cc (Cast Alum) 2002 CATALOG
Intake Valve Test Data @ 28" of water
.200--.300---.400---.500----.600----.700
132---198----240----260-----262-----N/A

Airflow Research 210cc (Cast Alum) 2002 CATALOG
Intake valve teat data @28" of water
.200---.300----.400----.500----.600----.700
135----197-----245-----273----282-----285

I won't bother posting other brand #'s because AFR is known for their great flow numbers, and their CNC'd heads flow awsome...then so is the price. Too bad Protopline went south, cause they were knocking on the door of greatness when internal trouble/strife sealed their fate. They're still made on a limited basis...but I wouldn't trust them anymore. I still have their catalog from when I bought them 2yrs ago for my L-48 '77. The AFR 210's obviously kick azz at .500 & above, and may have the best flow #'s at that runner size. Maybe in the near future I can afford them. Funny how many of the head manufactures WON'T publish their numbers. I've emailed many and got few responses.
Thanks for all your replies, info, and patience with my stupid dumb-azz questions. I'm am now an enlightened guy
Eddie
P.S. will call ya tomorow Kevin

 

I'm running a Comp 236/242 hydraulic roller with a 112lsa on a billet core. Idles nice at 1000rpms, pulls hard to 6000rpms. It pumps 500hp respectively at around 5500rpms. this is on a 10.2cr 383, with 6" rods, 1.6 roller rockers (.555/576 lift), AFR195s, and a port matched Victor Jr. intake. The wider lsa makes it very friendly on the street...Should do very well on your 406 combo.

 

That's the cam! You will have to go with the 1.5 rockers though. you will be at 520 intake lift and 540 exhaust. The 112 LSA makes this setup! I have the same situation and actually went with the 1.52 Comp pro magnom rockers. Will give you 527 lift on intake and 547 on the exhaust which will work fine with your springs if the are rated at .550 lift as mine are. There is a safety margin built in to the spring height. With a properly tuned 406 I would think you should have a little more than redshark6974