Info on Edelbrock heads

[tufcj]

Pulled from another site. Flow numbers, and a warning on the valve springs.

http://cgi.amcforum.net/cgi-bin/yabb...num=1091639779

[jeepsr4ever]

We have mapped the ports and will begin port work. The goal with the heads I am porting is to pick up the low & mid lift flow numbers. The heads flow enough air to build over 500 H.P. with the correct equipment to match. I had a set of Iron AMC heads which made 565 on a 390 engine, the flow numbers are pretty close to these across the board. Peak numbers on those heads were 280 intake, 198 exhaust. I hope to have new ported numbers early next week. Plans are to widen the floor of the intake, raise the intake just a bit, and Polish everything. We will work the exhaust very close to the same as a stock cast iron head. Behind the bolt hole above the dog leg, and the port roof. As far as these flow numbers matching the ones Edelbrock puts out, I don't know. I have not sat down yet and compared them. As far as the numbers I got go, the may well vary from Edelbrock, or anyone else. No 2 flow benches are alike. A flow bench is only a tool. If you use the same Tool[bench] all the time, then you can tell a little better about what
you have done to heads. Since I have flowed more sets of AMC heads on this bench than I can count, I can rely on comparing these numbers to other heads I have had on this bench, and thus the performance they might give. There is enough air here to make well over 500 H.P. WITH the correct parts.

To anyone buying the new Edelbrock heads. DO NOT INSTALL THEM Right out
of the box unless yuou want major problems. The very first thing
''Wrong'' with the heads is the Valvespring/retainer package. The
springs carry 142thru 148 pounds of spring seat pressure. This amount of
pressure will flatten any hydraulic cam, and would likely damage a solid
as well. 100-110 pounds is abpout all a Hydraulic cam will live under.
Most solids don't set up past 135 pounds unless it is super high RPM
race unit. Many Roller cams only use 165 on the seat.

[jeepsr4ever]

After talking with Randy we came to the conclusion that this would appear to be a common practice with all head smfgs...any head you buy will not be a direct bolt in for any setup...you can change valve spring and retainers pretty cheap to get these to work with hydralic cams....just like all other heads. Indy for example lets you customize you head parts.

[fuzz401]

tufcj he beat me to the post

[fuzz401]

Hello everyone! I am a design engineer at Edelbrock Corp, and upon hearing of this web board and posting, we decided to make our own contribution. Here is what my coworker has to say in response to this "warning", from the man who designed the AMC heads! Also, I had a hard time posting on the AMC list, so feel free to send this their way!

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From the Desk of Ulises Gonzalez, Edelbrock Corp:

Randy sounds to me like a man who makes his living out of selling porting work and performance modifications. He sounds in disbelief that perhaps the Edelbrock heads start working where his best effort on iron heads runs out of steam. I do not see any other reason why he will be so eager and overzealous to find and point out problems with the new head. There are plenty of good qualities he could be talking about, instead, he is desperately focusing on finding flaws as quickly as he can, so he can "convince" AMC enthusiasts that he is looking out for their best interest, and defending them from the evil Edelbrock.

Of course, this is the same Randy that relentlessly harassed the sales staff at Edelbrock in order to be the first person out there with a set of the new heads.

The Edelbrock heads were tested on a mildly stroked 401 engine. Since the crank was worn out, the rod journals had to be turned down in order to be able to use readily available, inexpensive 6-inch Chevy rods. This allowed for a slight stroke increase by grinding some offset into the journals. The final combination yielded 416 cid. With a Performer RPM level hydraulic camshaft with about .520-.540 lift, 230-240-degree duration @ .050" and 112-degree lobe spread, and 9.5: compression ratio these heads, untouched, without Randy's magic touch, made 450+ hp and 485 lb-ft of torque. Just imagine what they will make after Randy gets a hold of them! Oh, by the way, Randy, the guys at Edelbrock take about 20 minutes to perform the clean-up to get the numbers that took you 3-4 hours...

I'd like to point out that the test heads were assembled with 140lbs spring seat pressure at 1.875 installed height, and NO, they did not wipe out the cam!

Probably 99% of cam failures happen because of improper break-in or installation procedures (like lack of proper lubing), after all, the spring pressure just about triples as the lifter slides over the nose.
I would like to point out that, yes, maybe the spring pressure is a bit on the high side, at about 130-135 lbs NEW, but as anybody who has built an engine knows, a typical valve spring will lose anywhere from 5-10 lbs of seat pressure during break-in. Stainless steel valves with larger heads are generally heavier than OEM pieces. Just like a stronger retainer that allows the user to drop an inner spring right in if a roller cam was to be used, will also be heavier. If you want to be able to rev your engine to 6500 rpm without floating the valves, 125 lbs will be just fine. Remember though, these are street heads, they were designer with the average enthusiast in mind, although many people will be surprised what they can do in mild racing applications.

Edelbrock does not take a "one size fits all" approach. Heads are sold complete, as a tested, proven package, or bare, so that guys can customize their own. You do not have to buy the springs if you don't want them, Randy...

I'm sure Randy has a lot of years of experience working on AMCs, and perhaps, he might find it disturbing that an engineer with not as much AMC experience as he has can produce a decent AMC port. Here's a little secret for you, Randy, a good port is still a port, and a good porter knows that.

What smart AMC enthusiasts will be able to appreciate is the amount of experience acquired in other fields in both street and racing, which translates into improvements to this head.
Randy might find it beneficial and might be more profitable for him if he focuses on sharing the excitement by focusing on the potential and positive aspects of the head instead of trying to instill fear in the hearts of potential users. After all, when was the last time AMC users had a chance to make as much power for a fraction of what I would cost to port iron heads? People can see desperation in businesses that try too hard to peddle their services by knocking good product.

I'll be looking forward to seeing Randy's progress on porting these heads. I'm sure he'll beat the socks off those Edelbrock rookies. I'm sure it is a great strategy to "work the exhaust very close to the same as a stock cast iron head"
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Thanks for your time!
Roger
Design Engineer
Edelbrock Corp

PS - The combustion chamber is 54cc

[jeepsr4ever]

Yes I have talked with Randy on this subject alot. We discussed the highs and lows, although he had just posted POSSIBLE issues with these heads and some concerns, what you dont hear is a sigh of relief coming from the AMC world and little thanks going on under our breathe. I say hats off to their engineers and hats off to Vic jr. for listening even though we badgered him hard about heads. I tried to work with Indy and get pricing and be a distributor, they were RUDE, CRUDE and DISRESPECTFUL. Now I know respect can be a day to day thing and I may approach them in the future, BUT I will give me nod to the Edelbrock guys because they approached this logically and were very nice to deal with. If we were to post negative stuff about the indy or herman lewis heads we would have MULTIPLE PAGES. Edelbrock went through their bugs first before selling these, It may have been the reason we feel they were hyped for so long before production....to which they may be at their capacity.