Folks,

I'm looking for some guidance here. Right now, I've got a mild 355 (.510 hydraulic) under a pair of 'stock' vortecs that are port-matched to my new monster MPFI Holley intake. However, I'm a bit hungry for some mucho-more power. I miss the 383 (deceased). :^(

Anyways, what I'm planning is a Dart Lil'M Eagle 434 short-block with a Comp Cams 236/242 .560/.570 solid roller. Not sure of the target compression, but JE Piston selection will be based on that. Probably around 10.5:1, with the overlap and good EFI should be able to get away with it on 92/93.

While I could get some all-out flow numbers with Pro Topline full-CNC stuff for old-style pattern, I want to see what I can get out of some Vortec-style units. Options include:

1) Beefed-up / port-worked stock iron units.
2) Edelbrock E-Tec 200s, with some polish work and spring upgrades (Recommendations here? Part #s?).
3) Brodix heads (I've seen reference to them having Vortec-style, but can't find them. Part #?).
4) Some other Vortec solution as yet undiscovered.

Anyone have some perspective here? How much can be gained on the E-Tec 200s in terms of flow before/after port work? Should I just scrap the whole Vortec fixation? Can a standard-pattern set of heads be drilled for a Vortec intake?

Many thanks,
-Craig

 

Since you already have the vortec intake I would stick with Vortec style heads. I think the E-Tec 200's or the GM Fastburn heads would be a good choice. They still have the most efficient combustion chamber of any standard Chevy except for the new Gen II and Gen III engine heads.

 

Yeah, that's where I'm leaning.

So for that case, what kind of flow numbers can be had with some port/polish on the FastBurn or E-Tec heads?

Also, what sort of spring provisions will be needed to handle that cam safely? Solid roller, so I figure at least 160# on seat for street use, with maybe 450-500 at 0.500?

 

dynoed a set of etec 200's with diff springs/studs etc , and no port work at 430hp and the torque to match on a 350 with a xe274 cam derivitive...

goood heads, and with some over all improving in the flow, should net some pretty damn good gains.

However i caution you to buy a non assembled set of etecs - the stuff on top is junk for anythin more than mild... buy a decent set of valves/retainors etc, some good springs and some screw in studs w/ retainors and do things right...

You sounds pretty on with the springs, but i would just stick with a step over what the cam card specs out for a spring..


edit... those heads are going to be small no matter what IMO for a 430ci motor... i would think you would rather have something close to a 210cc head for a 400+ ci motor... i'm not sure your going to be able to hog them out enough to make a solid enough gain to support a hell of a lot of hp... you can expect a ****load of torque down low tho!

 

Not sure what you are looking for power wise or efficiency wise. The E-Tecs are so good because of the port/combustion chamber design. It's easy to open up a port and flow more air but it not easy to retain the same swirl/mix properties of the stock setup. This can end up hurting your performance. I would say a good set of ported GM fastburns from someone like Wheeler would be just what you want. Wheeler did my heads, I left the intake alone as I felt it was fine for what I was building.

 

I got me a set of E-Tec 170 heads on my 385. They were a decent set of heads out of the box however I took the liberty to give them a bit of work to suit my fancy. I scored the set for $900, new, complete.

If you look around you would be able to find a set of 200s for less than $1000.

Everyone had told me, "oh you better watch out running such a small head on that 385 motor" LOL though as I couldnt be more pleased.

Laughing all the way down the track.

Motor:
385, CC XR276HR-12: 224/230 .535/.540 on 1.6, SDPC base with Superram Upper, STock 48mm TB, E-Tec 170 heads, Hooker Supercomp LTs.

Solid Roller cam upgrade and 58mm TB planned for this coming winter, and some slicks to get the TQ Pig hooked up, and a job to support these new mods, thank "***" I just graduated.

Anyway about the heads, they come out of the box with screw in studs and guidplates 3/8", valves are SS undercut, so they are good to go. Only thing that will HAVE to change is the springs. If the cam you are looking at is an XE Solid Roller than a set of CC 977s are what you need, with matching locks and retainers.

A skilled hand can free up all the flow you want in set of heads.

 

I have a set of GM FastBurns that are set to go on my 409 project.

They will need "cleaning up" before using them. I was slightly dissappointed in GMs quality control on my set. Such as heli-coils hanging down half a coil into the intake runners, casting ridges that could have been taken care of before delivery and the slightly smallish valve springs (1.34+-) o.d.

I'm using a cam bigger (.560) than the springs rated .525 lift and the choice of springs bigger than that is limited in the o.d. size the heads are cut for. Not a real problem to install bigger springs but I'm just giving you a "heads up".

My biggest problem with my FastBurns is the d-shaped exhaust port. They are TOO big for any header (that I have seen) that fits my GTA chassis.

I have a set of 1-3/4" SLP headers on my car currently. Before I put them on the car, I bolted them to the heads (with no valves) and there is CONSIDERABLE blockage by the headers at the exhaust port flanges.

I even considered "porting" the SLPs but after doing some measuring, I concluded the flange would be cut dangerously close to the top (probable exhaust leak) and, in addition, the width across was not enough to keep from possibly grinding through the weld (next to the exhaust bolt holes). Also, the bottom of the round header tube is close to not covering the head surface before it angles away from the machined flange of the head.

In short, what I am saying here is many people think any third-gen header works on these big D-port heads. Technically they do fit, but they don't "work" well.

If these heads were intended for a 350ish engine, maybe a slight blockage would be acceptable with the headers.

You stated you are building a BIG small-block so I believe you would need a custom set of headers (or perhaps, like me, consider welding a d-port flange to my current headers).

If you find a "proper" solution, please let me know.

I have flowed my heads twice, once just out of the box, and then again 3/4 way through my port-matching/cleaning up efforts (just to make sure I wasn't "unbalancing" the flow.

They flowed slightly above or at what is shown in the GM Performance Parts catalogs. I really like their mid-range (up to .600 lift-where I stopped the tests) and they showed no signs of stalling like some of the aftermarket heads tend to. The low lift exhaust flow is a little weak, in my opinion, but the i/e flow% comparison, IIRC is in the high 70s% range.

Would I recommend the FastBurns? I think their benefits outweigh their downside, considering I wanted "GM" parts on my engine (so as to point at it and say "It's all GM").

We won't get into the almost stock looking TPI with the aftermarket intake (--Scoggin-Dickey is GM, right?) and yeah, yeah, I know, I could pick up a ton of power with other intake choices but I wanted stock appearing.

jms

 

Did you consider Pro Topline's vortec heads? They are supposed to outflow GM's vortec heads and they cost about the same.

 

Yes, but I was hoping to go with something that can do the following:

1) Be aluminum for more compression allowance and ease of port/polish/repair.

2) Have 2.00+/1.60+ valves with 1.40+ diameter springs

3) Flow 250+/170+ out of the box

4) Flow 280+ / 190+ after port/polish

5) Handle 0.580 lift

Tall order? Anyone have actual flow bench numbers from some 'worked' Vortec-style? Maybe FastBurn or ETec or TopLine?

 

on the www.chevytalk.com forum in the performance section rickwi has posted on semi-ported 200cc e-tecs. he is very happy with the numbers he got. he stated that with a full port job could easily flow over 300cfm.
a big problem i've read about with both the fastburns and e-tecs is they come with valve jobs that aren't that great but the port and chamber design is killer.

 

...hummm..you cant race a flow bench

 

Wasn't there a fairly recent thread about a big port set of Vortec heads from GM. IIRC they had 206cc ports. I never saw any flow numbers for them, but they ought to flow really well with that design.

Adam

 

https://www.thirdgen.org/techbb2/sho...hreadid=248921

Here is the thread discussing the new vortec style heads.

 

Any flow numbers on a well-ported set of E-Tec 200 heads yet?

 

Not sure if this will help anyone out or not, but just for reference, I went 12.10s and 12.20s consistenly on box stock E-Tec 200s. The rest of the motor was a 355, dual plane intake, 750HP Holley and a Comp Hydraulic roller.

Hope that helps someone

 

That's good. What were your cam specs and what not? Stock ETec? No spring upgrades?

 

XR294-HR , and yes, the springs were upgraded to 987s. Other than the springs to match the cam, the heads were untouched.

It was a street car with a 2004-R transmission and a 3200 lockup stall.