Looking through the afr website and comparing the street 180 and 195 heads, they are pretty much the same flows. The 195's are a tad higher on the intakes, but the ex are the same. Which one would be better to use? Probably not going to turn over 6200-6500 in this motor. The CHP engine they did made almost 500hp with the 180's and a small hyd camshaft. I'd like to build something close to that. Is 180 too small for a street/strip motor? Thanks for any info.

For a 406 I would use the 195.

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70 SS 454 CI Dynoed 684 HP, 702 TQ All Aluminium Fuel Injected Small Block , plus 200 - 500 HP NX nitrous system.

I would go with a set of 227s, you are going to want to step things up someday, why buy another set of heads when someday comes ???

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1970 1/2 RS Z28 S.B., Pump Gas, Radials, Full Tails ( 3 1/2" ) 10.59 @ 129

I bought a set of 220's for my 355 so that I can move up later,cheaper now then later.

Anything over the 210 starts getting strange with the valvetrain...
I would either look at the CNC ported 195's or the off the shelf 210s for a 406
The 180's are too small a runner for a 400cid motor

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1971 Camaro
383 stroker ~500HP
M21 4spd
12" brakes
16x10" Wheels
Autocross competitive
Sales / Tech - The Speed Merchant, San Jose, CA
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I used the 210 because I figured they were flowing similar to comp ported 195s, probably with comparable sized runners. Dont know how many CC that comp port adds to the 195s. Also, I believe the 210 is a different casting than the 195 and can be ported to a greater extent in the future. So if you get the 210, it will work well on a street 406 now, and when you want to go wild in the future, have it professionally ported for another $1200 bucks or something and you'd have a real decent head.

I dont really know much about all the high end stuff, I'm more into the street car application. But I thought the 210 was kinda at the merging point of those two genres on a 406.

I read a few articles and they say not to go over 200cc for a street& mild strip motor.

I have the 195's on a 350+.060 with mild solid street roller and I really wish they had more top end power.

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1978 Z-28 purchased new by me -$6750
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1994 Formula
1982 350 S-10

Re-read that CHP article on the 406 with 180 AFR's that made 490HP. If you read real careful and close they just breeze over that the 180's are competition ported, and full CNC. That will put you over $2,000.00 for 180 runner heads, and that is how you make 490HP with 180 heads.
There are 3 levels of porting from AFR, Std, CNC, and competition CNC, be careful what flow numbers you are reading, some of the full comp CNC heads are $2,795.00.
180, 195, and 210 will take standard valve train, the 227 full comp need offset lifters, and special girdle. A few guys have custom cut and made guide plates to fit the 227's, but I think thats risky myself to cut and weld guide plates.
My pick would be 195 CNC for 350, 210CNC for 406, but to take advantage of those, a solid, or solid roller to get the valve lifted as fast off the seat as possible in the low lift area. AFR advantage is the low lift flow numbers, so match the cam to the heads.
CHP's 490HP 406 used a small hyd, but full race port 180's. A solid roller on that same 406 / 180's probably would make 535HP.

Not to difficult to make 575HP with AFR210's solid roller combination.


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406 Stroker Brodix 200CC Race Rite Heads
Tremec TKO 600 5 Speed

I'm going to use a solid cam for sure. Can't see the expense of a roller set-up for what i want to do. Too much money to get a set of lifters that will live with street use. Probably going to get a custom ground from UD harold. Whats the best chamber cc to use? Some people say small like 64 is good, and other say 72 or 76 for more room?? What do you guys think?? Also what is better straight plug or angle? Does it make a difference in performance?

[This message has been edited by BLKnBad71Z (edited November 25, 2004).]

I don't think I have ever seen a definative and tested answer on power difference angle plug VRS straight. With the new generation CNC type heads, I don't think there is a lot of difference in a street engine.
I have done however some research on head chamber size. My take on it is that you want the smallest chamber possible. In simple terms, you do not want the explosive pressure pushing up against a big expanded chamber with lots of surface area. You want all of the force pushing DOWN against the piston. In a small chamber, the only room for expansion is DOWN.
Dome pistons try to fill a big hole with volume, my research said a flat top, or in my case a slight dish made best power on my 406 with 68CC chamber.
I am sure there are lots of opinions on this topic.


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406 Stroker Brodix 200CC Race Rite Heads
Tremec TKO 600 5 Speed

If you talk to AFR they will recommend their 74cc heads as being more efficient than the 68cc ones. The shape produces less valve shrouding, better swirl, etc for higher VE. You want to select a combustion chamber that produces your desired compression.

In a small chamber, the only room for expansion is DOWN.
In any ICE combustion chamber the only room for expansion is down.

In simple terms, you do not want the explosive pressure pushing up against a big expanded chamber with lots of surface area.
You can't push down on the piston unless you push up on the head.