I was looking at Small Block Pro Action 14 degree CNC heads with 285 cc intake ports and wondering about the advertised flow numbers. Does anyone have experience with these heads. Any independant flow numbers.

They advertise intake:

.3" 234 cfm
.4" 299 cfm
.5" 353 cfm
.6" 383 cfm


These seem like they would make awesome heads for a 440 to 454 cu.in. tall deck SMALL block if the flow numbers are accurate.

The flow numbers are on their web page:
http://www.procylinderheads.com/aluminium_main.htm

 

Yes, they would run great if you have the money to run Kinsler fuel injection with 15 to 1 compression and methanol for fuel. Great power band from 6400 - 8600 rpm. You can lift your front tires off the ground at 100 mph in a 1320 pound sprint car. They cam them to make TQ so they only make about 800 hp in a 410 ci motor.

The Key word is "285 cc intake"

 

Those are certainly awesome flow numbers, especially the .300" lift number. 234cfm @ .300", that's almost unbelievable, especially from a 285cc port. There are alot of heads that don't even flow that much at .600".

 

Gkull is right on, not streetable at all, unless you are looking for 800 + HP :chevy

 

Monty - Aren't companies bound by deceptive advertising laws? I have been in contact with a person at Dart who is involved with flow bench and design work. He told me that their posted flow figures were repeatable with any head out of any box within less than 5%.

Instead of buying new heads with all new shaft rocker setups. I've been searching for improvements. It really comes down to my intakes are near the max cfm for .600 lift cfm and exhaust short side radius work could get me slightly more cfm across all lift ranges without changing the exit dimension which would require bigger than 1 3/4 headers.

So I'm stuck with these. I didn't go with full CNC. Mine had factory work and then a local speed shop. all my figures are very close to this site. :)
http://www.dartheads.com/sbpro227.htm

 

George,

I think that head companies can pretty much claim any flow number they want, because different flow benches will yield different results. I always see heads that flow less on a bench than what the head manufacturer/porter claims, but I can't ever recall seeing a head flow more on the bench than what the manufacturer/porter claims.

I just looked at the Dart site and the data for my Dart 18* heads - http://www.dartheads.com/sb18sbc.htm, the flow numbers that they show for the intakes are nearly identical to what we saw on the bench at Fast Times, while the exhaust was actually better, especially at .300" and .400". Of course, some of the difference could be how much attention to detail the person paid who was doing the flow testing. My Dart 18* heads were CNC'd right out of the box, we didn't do anything to them other than put them on the flow bench to see what they flowed, mostly out of curiousity. I don't think the old Dart site had flow numbers on it, this is the first time I've seen Dart's claims for these heads.

Valve Lift.....Dart's Intake Claim.....My Flow bench #'s.....Dart's Exh....My Exh
.200............138..................... ........132............................1 11..............111
.300............192..................... ........197............................1 54..............188
.400............250..................... ........258............................2 15..............224
.500............304..................... ........309............................2 41..............242
.600............346..................... ........346............................2 53..............253
.700............373..................... ........355............................2 58..............260

The site also listed some intake flow numbers witht he addition of a 32* back-cut intake valve, and the intake flow really jumped up. Since I'm replacing the exhaust valves with some Inconel valves, I might look into checking out some of the 32* valves as well!

Valve Lift Intake Flow w/ 32* B/C valves Difference b/w current intake
.200.............136.................... ............................-2
.300.............213.................... ............................+16
.400.............274.................... ............................+16
.500.............323.................... ............................+14
.600.............359.................... ............................+13
.700.............378.................... ............................+13




[Modified by Monty, 11:16 AM 4/2/2002]

 

Monty - I'm not up on the effects of blower motors and the effect of max porting and back cuts to get that extra ounce of cfm. The Dart 227 is a new product. Mine were purchased as and have a cast on " Pro1 215 cc " With a stamped on different product # I ask for extensive mods including the 2.08/1.625 valve size. They must have thought that it was such a good idea that they have brought out a new product. I guess I should have gone with 2.10/1.6 like I originaly considered during my first discussions with them. :lol:

For anyone on the forum I would recommend them for all street/strip 383 and up applications. anybody that knows heads understands that over 300 cfm is not that easy to attain.

 

Those Dart 227's look pretty good, besting AFr's Full-Competition 227's overall.

For comparison, here's what AFR claims for their 227cc heads....

The AFR 227cc w/ Race-Ready porting:



The AFR 227cc w/ Competition porting:






[Modified by Monty, 11:58 AM 4/2/2002]

 

I'd like to see a LS6 head ported and see how those numbers compare to the AFR227 competition. It seems that now a days tuners are getting 310-315 cfm out of the LS6 heads with good porting.. Is it possible?

 

I believe LS1/6 heads are 14* or 15*, so it wouldn't surprise me. Alot of effort by GM engineers went into designing those heads.

 

I have Lt-5 ported heads flow numbers, is not too relevant for this topic, let me know if you guys want me to share them..

 

I'm always interested in seeing flow numbers....

 

I'm talking about using them on a 440 or 454 rocket block setup. It seems to me if Monty is using 257 cc intake ports on a 427 and has the broad torque curve he has, another 28 cc along with 27 cu.in. wouldn't kill the torque. These heads compare well with a good set of big block heads. Use the 14 degree Pro Action single plane intake converted to fuel injection, a mechanical roller, custom 2" headers and you essentially have big block power that fits, weighs and looks like a small block. I'm not saying it would be cheap. I'm looking for an alternative to power adders that will make about 700 flywheel HP and still be streetable. Similar to Monty's 427 that makes 650 hp before the turbo.

Looking at the numbers Monty posted for the Dart 18 deg heads with 32 deg back-cut valves I would geuss the Pro Action numbers are possible but I'd still like to know someone who's flowed them before I go down this path.

 

here it goes...

Greg Van Deventer Machine 11/26/2001
14919 E. 6TH ST.
Yale, Oklahoma 74085
(918)387-2837

Cylinder Head Flow Data


Customer name:
Date: 10/6/2001
Type: Chevrolet
Model: LT5 LH LT5 cylinder head, cly. # 3
This test is after re-work.

Intake Lift Intake CFM

0.450 308.28

0.400 299.47

0.300 254.91

0.200 187.52

0.100 97.53


Exhaust Lift Exhaust CFM

0.443 245.55

0.400 236.62

0.300 212.07

0.200 172.21

0.100 87.10

 

Torquejunky,

I think you're on the right track if you go that big in CI. As you alluded to, you've got to almost think in terms of a Big-block when you go that big in displacement. That's the main problem with building a big0inch SBC, finding heads that flow enough.

I'd think you'd easily exceed 700hp. When we dynoed my SBC 427 I didn''t have my custom headers weren't done yet, so we just used a pair of 1 3/4" Dynotech headers that were laying around. 1 3/4" is obviously too small for a 427ci+ engine, but it still made 650hp. We never did redyno it with the 2" headers, but I'm sure it would have made arounf 700hp, which was my original goal. I would be surprised to see yours come in over 700hp on pump gas with those heads if those flow numbers are accurate.

If you decide to build it, good luck. If there's anything I can do to help, feel free to ask. And don't listen to the naysayer's. When I built my SBC 427 last year, and stated my power goals, you wouldn't beleive all the people that came out saying it couldn't be done. Unfortunately, there's alot of people in this world that don't like to see other people succeed.

 

Those LT5 flow numbers really illustrate the superior low valve lift flow of a 4 valve head. 300cfm at .400 is darned efficient.

 

Monty, thanks for the offer to help. I've already learned a lot from your web site and messages on the forum.

I've made some rash purchases (supercharger) for the car and have regrets. I need to consider the big small block very carefully before I do it. If I didn't already have a supercharger .... the big small block would be a slam dunk.


[Modified by torquejunky, 2:16 PM 4/2/2002]

 

What's wrong with an SC?

How about a Supercharged SBC 427? That'd be cool.

 

I can't remember his CF name. Aaron in Texas and posts on this mods section. But anyway he has a killer SC 4 inch stroker 350 based small block with 408 ci 4.030X4 inch and I thinks it's rear wheel dyno was 600 hp.

 

Monty, Nothings wrong with a supercharger in general and a 427 SC would definitely be cool. I just have some regrets about mine. I have an 86 vette and the ATI D1 intercooled kit. I haven't installed it yet but I can already tell I'll be replacing a lot of stuff with custom fabricated or modified parts to make it do what I want. When you consider the cost of doing a supercharger for my car the right way, it will be almost as expensive as the big small block (both built for about 700 hp). I would rather have the big small block. The disadvantage of the supercharger is noise, belt life, crankshaft wear, heat, reliability, clutter in the engine compartment. The only disadvantage of the big small block I can think of is gas mileage and I'm not concerned about that.

I have a pile of new parts for the supercharger build-up minus a short block. (accumulated over the last 2 years - AFR heads, miniram, retrofit hydraulic roller, headers, D-1 kit ....) I can sell them new in box at a loss and go for the big small block or just move forward with the supercharger. If I move forward with the supercharger and change my mind, the parts will be used and I'll take a bigger loss. I need to make a decision before I build the short block.

The reason I didn't originally go with the big small block is that I didn't believe you could build one that would make 700 hp and still be what I consider streetable. I was wrong as your 427 proves. With the availability of small block heads that flow like yours or the Pro Action 14 degree heads, I'm really considering the big small block.