75 BBC Stingray

Just looking for some opinions...

I am building a 454 +.030 that has the ACCEL superram DFI unit. I need to buy heads soon. I have been looking at several heads:

1.) Brodix OEBrodix OEFI Aluminum Oval Port - around $2,000
2.) Dart Oval Aluminum - not sure of price, guessing $1,800 - $2,000
3.) Edelbrock 454-O aluminum oval port - $1,700
4.) World Products Merlin Cast Iron Oval - $1,300

The cam I am running is PowerMax Hydraulic Roller
HR-288-2S-12 IG
Duration at 0.050" : 226°/234°
Advertised Duration : 288°/296°
Lobe Separation : 112°
Open/Close at 0.050"
Intake : 6 / 40
Exhaust : 54 / 0
Lift : 0.587 / 0.610

So here is my thoughts:

1.) The Edelbrock has the largest intake port of all of them, but I plan on having this motor only between 2K and 5Kmax RPM, and mostly between 2,000-3,500RPM. I don't want a head that is "too big"

2.) The Brodix has the smallest intake port (should = better throttle response/torque), but the price is high.

3.) The Merlin is the cheapest and I've heard good things about it. But its cast iron. I'm just not sure if $400 (price from Merlin to Edelbrock) is worth a weight savings of 80lbs? (Its approx. 40lbs per head right?)

4.) If I put the $400-$700 I would save buying the Merlin, I would be able to get some porting done, and maybe have even better performing heads than some of the alum heads out of the box...

The pistons I bought, have a small dome to give a 10.5CR with a 110cc chamber.

Any thoughts? I just want my vette to be a nice powerful "toy" to drive on the street. I'm not going racing (drag or auto-X). I'll spend the extra money if I think the gains are worth it, now I'm just not sure.

427Hotrod

Well all your choices are good ones. Here's my take...

First, I ran a set of Merlin iron ovals and they were great. BUT...these had been seriously professionally ported/angle milled etc. Fantastic heads, but out of the box they are a little rough as most iron heads are. Plan on doing some work. And they are heavier than stock iron heads.

The Edelbrocks are from all indications a pretty good head. If you do some checking you can find the GM versions pretty decently priced. You can also get them down to 100cc out of the box. That will really help compression as all these heads normally are much larger and with normal .017-.025 GM deck heights, your compression is often much lower than you planned especially when using .042 or so gaskets. Need much tighter deck or thinnner gaskets. Like the others, they respond well to cleanup porting.

The Darts probably have one of the best flowing ports out of the box. Lot of discussion but Darts are also considered by racers to be one of the "lightest" aluminum heads. Not a big deal but some folks really question the casting integrity. But they are a very popular head in racing so must not be too bad huh?

Brodix ovals also flow very well. I'm sure the Brodix or Darts probably out do the Edelbrocks out of the box. Brodix is known to have a very strong porosity/core shift free head in case something ever happens. They are also very conservative in their advertised flow numbers, not much hype. I can tell you that my set of Brodix flowed better than what they advertised after two years of running (old original valve job) and no port work.

You might also check AFR. They have some small 305cc rectangular port heads that flow great and are about to introduce an oval port version, but I can tell you there is usually a long wait to get their stuff unless you are really lucky. Castings are good and they are probably the best flowing out of the box heads out there, better than the Darts even.

Issues are going to be raised ex ports on most of the better flowing heads. It can cause header issues. The Brodix are raised .600 and will most likely cause header issues. The Darts are similar. The Edelbrock/GMs are stock. The Merlins I believe are raised a little but my headers fit fine. The AFR's are raised about .300 but everyone reports they fit fine.

Chamber size...most have chambers in the 119cc range and will require milling for you pistons.

Double check things like bolt holes being drilled in the ends for accy's and holes for temp senders if needed. Some don't come that way and have to be ordered.

Bottom line, is port work is worth a lot. A professionally ported stock GM head can often come real close to these aftermarket heads. But a little work on these makes them really take off. Porting is expensive unless you do it yourself and can get acess to a flowbench. A good CNC out of the box head either from Brodix, Dart or AFR will make unbelievable power, yet be pretty pricy. For what you're doing a nice set of Edelbrock 100cc heads with a little cleanup work is probably the best bang for your buck. The other heads with more work will shine in the upper rpm ranges that you aren't going to be going to.

Now if your parameters change....then we can REALLY have some fun!

JIM


[Modified by 427Hotrod, 9:57 AM 9/17/2003]

Crickett

Definately go with alum.!! You'd save soooo much in weight! :thumbs:

Fevre

Looking at your cam selection it appears you are not going for all out power so I would get your comp ratio down (9/1 with iron or 10/1 with alum) so you can run lower grade gas. That cam will not bleed off much comp so you might run into detonation problems even with 93 oct if your comp is too high.

zwede

427 hotrod summed it up well. Just like to add that there is a noticable difference in handling when going with aluminum. The car is nimbler and more fun on the street.

WA 2 FST

I can highly recommend the AFR heads. Who cares if they are rect. port if they keep high port velocity at lower speeds? :) I've seen a recent test with their 305 "as cast" heads vs. the L88/ZL-1 heads and the AFRs outflowed the hi-po GM offerings at all valve lifts from .100-.700". However, since the runners are shorter, they keep port velocity way up there...meaning no sacrifice in bottom-end TQ.

I also chose a "small" cam, and did not want a drag racer that gave up a lot of bottom end. Well, the end result with the AFRs was tire-scorching TQ off-idle, peak HP is at 5600rpm, and yet the power only drops off by 25 way up at 6400. So it was the best of both worlds.

The next thing I want to do with the car is put 3.08s in it...makes too much bottom end to use 1st at all, and it will light the tires from a roll in 2nd at 40mph pretty easily.

Oh, FWIW, my cam is a COMP grind (230/230, .587/.587, 110LSA) hyd. roller. Very mild.

75 BBC Stingray

Thank you all who responded.

WA 2 FST - I wouldn't mind the rectangle ports, if my manifold wasn't already an oval port. Since the manifold is an integral part of the DFI unit, I don't think I'll be switching anytime soon. I will keep my eye out for their oval port version however...

Zwede - Thanks for the input (as well as posting that EFI tuning page). My question is now answered as to whether one can notice the weight difference in handling between the cast and aluminum heads.

Crickett - I guess my next question in how much is sooooo much. I was thinking about 40lbs per head. Now 80lbs is not much compared to a 3,800lbs car, but I guess 80lbs added that high up (about mid chest level) is significant when the car rolls side to side...

Fevre - If I go aluminum, I would like to keep my ratio at 10:1 or so. I am hoping the EFI setup will offset the higher CR and I will not have a problem. Thank you for the suggestion though...

427 Hotrod - Wonderful info, thanks! The feeling that I'm getting from talking w/ different people is that regardless of which aftermarket head that I get (of the ones listed), I will have a peppy ride and probably more torque than the tires will be able to handle. I am very curious about the AFR oval ports you mentioned... Any idea when they might be introduced?

Anyone else like to make some comments???

I also forgot to mention that I currently have 3:38 gears in back and will keep them for a little bit, at least until the rear gets sent out for rebuild.


[Modified by 75 BBC Stingray, 9:36 PM 9/17/2003]

427Hotrod

Tony Mamo at AFR says they will be out in a month or two, but historically that is very optimistic. He has created an excellent product, but the marketing folks went way overboard advertising their previous heads introduction LONG before any were really available.

You might still consider their 305 cc port. He uses a very unique radius in the port as compared to others (much "rounder") and your oval port EFI intake could easily be a perfect candidate to port match to the heads. Often, regular rectangular port intakes don't match well to his heads without a little port work in them. The Edelbrock Victors apparently are a good baseline to use. Anything smaller just gives you more room to work.

The 305 heads flow nearly 360 cfm at .600 lift and the lo-lift numbers are fantastic. They will just flat kill any of the ovals you listed. For example my Merlins after beautiful expensive flow bench work were in the 324 cfm range @.600 lift. Of course they could have flowed more if we opened port more, but on a 427 they were perfect. Edelbrock ovals can go into the 325-340 range with good port work also, but they are a long way from there out of the box.

I'd call Tony at AFR. 818-890-0616 He's a real nice guy and will really help you work the deal out. You could easily get some of the new ovals before anyone else! But I bet he wouldn't feel bad about using the 305's either!


JIM

69 N.O.X. RATT

I have a set of the Edelbrock ovals and after much porting they flow 318 at .650 with pretty much the stock port size.

I am with Hotrod in checking on the AFR's they or maybe the Pro actions are the best off the shelf head there is. Do yourself a favor and get a bigger cam, even though you want to keep rpms low (which you will re-evaluate the first time you stand on it) Don't cripple a great set of heads with a pitifully small cam.

Look at Wa 2 small of a cam's :lol: motorbuild. I assure you he has excellent throttle responce and the motor makes very streetable power through out the rpm range.

75 BBC Stingray

427 Hotrod - Thanks for the number, I will definately give a call. I don't need the heads until around January. My plan is to have the chassis/suspension/brakes done for next April so I can drop the body back on and drive the car some.

69 N.O.X. RATT - I guess the cam is a little small compared to what is out there, but I would be very woried about the EFI units ability to function well with a big cam. I would think at a certain point, the vacuum signals to the MAP sensor would get erratic, and the tune would be jumping all over the fuel curve. Also I've read that 230° (@0.050") is max duration if you want to run a knock sensor (which I do have). A rumpity engine will cause the spark to retard, as the sensor thinks it is detonation.
In any case, thank you for the responses.