Joined: Sat Jun 07 2008, 12:59AM
Location: Fort Lewis, Washington
Posts: 394
Anybody running any of these heads? Any opinions/bitches/gripes/complaints? For a fully assembled set of heads I can't really beat the price, even if they are cast iron. As per a few suggestions on here, my application would be worse off with the Eddy aluminum heads. Mancini Racing sells the 452, the 906, the 516, and the 346 casting number heads. I know the 906 is the desirable closed-chamber head...what kind of gains could I expect over my stock 66 heads?
Joined: Sun Oct 09 2005, 05:02PM
Location: ALLEN PARK, MI.
Posts: 2007
Ah 4 door, I wouldn't go as far as calling a 906 head "CLOSED CHAMBERED" per say. The only head Ma Mopar made to that effect I can remember was the 67' Hi-po head, which the Eddy 84cc head is something like. Never heard any "BAD" about the Aero stuff yet! Tony P.
Joined: Mon Jan 16 2006, 02:52AM
Location: Vantaa,Finland
Posts: 379
Aerohead is a "sister company" to Indy Cylinder heads. their address is the same, or at least used to be, haven't checked lately. They are ok heads, nut not much less than Stealth heads which easily outperforms them. The only "new generation" wedge heads with closed chambers are the '67 915 castings.
Joined: Mon Oct 10 2005, 05:03PM
Location: CR, IA
Posts: 762
The website says this:
wrote ... Aerohead Racing Component is a stock division of Indy Cylinder Head. Aerohead concentrates on improving factory O.E.M. cylinder heads for the budget oriented engine builder that is looking for a high quality product.
The 516's are the closed chamber heads, but they have terrible port designs and mountainous valve guide bosses blocking the ports-I would not waste my time/money on those. The 915 was a one year only ('67) closed chamber head with a slightly better port design and larger exhaust valves than the 516's, but the throat of the exhaust port is still restricted and they had the huge valve guide bosses. The intake port design would be used on the later 906's.
The 906 heads are the first open chamber ones, used from '68 -70. They still had the big valve guide bosses, they flow good in stock form, but require a lot of grinding to blend the bowls/port.
The 346 heads used from '71-73 are open chamber with a redesigned intake port with a "Huber Hump" to add swirl to the incoming charge and reduce pollution. These were the heads that Richard Petty used in his NASCAR cars after the Hemi was outlawed (he won about 75 races using them). The 452 heads were used from '74-78 and are the same as the 346's but with induction hardened exhaust seats.
Both the 346/452 are the easiest to blend the bowls and port. The 906-346-452 all flow about the same, but ported 346/452's will easily outflow ported 906's. I'd use either of the 346/452 castings with hardened exhaust seats and have them do a 70 degree cut on the port throats so you can easily blend the bowls.
I have been using a set of these (346's with hardened seats and 2.14" intake, 1.81" exhausts) for a couple years now and have been very pleased - they work great on a 383. I did a little extra work on them - blended the bowls, back cut the valves, polished the chambers, and gasket matched the ports.
For the money they can't be beat!
Now, for the power gain over your '66 #516 casting boat anchor heads-the 516 head equipped 383 2bbl was rated at 270 Hp - the same 383 2bbl with 906 heads was rated at 290 HP. With mods like a cam, intake, headers, etc you will see at least 40 more horsepower using the 906/346/452 than you would using the 516's.
Joined: Thu May 01 2008, 11:15AM
Location: Chicago,IL
Posts: 2868
Actually, the 906 intake port design offers a superior mid lift flow number that translates to power in a street car vs the later intake design. The later design is easier to do 'stage 1/2' port work to without screwing them up and they respond quicker to that level of work. Lots of good stuff on moparts from Dwayne Porter about all this. If you're buying a stock casting with just backcut valves and a performance valve job and don't plan on having anyone do any template porting to them, I think the 906's are worth the extra $100 in flow.
Joined: Sat Jun 07 2008, 12:59AM
Location: Fort Lewis, Washington
Posts: 394
Thanks for the info! I think I am going to go with the 906s and have a little work done to them before I install them. $699 from Mancini Racing for a fully assembled set of heads...I cant beat that deal with a stick!
furious70 wrote ... Actually, the 906 intake port design offers a superior mid lift flow number that translates to power in a street car vs the later intake design. The later design is easier to do 'stage 1/2' port work to without screwing them up and they respond quicker to that level of work. Lots of good stuff on moparts from Dwayne Porter about all this. If you're buying a stock casting with just backcut valves and a performance valve job and don't plan on having anyone do any template porting to them, I think the 906's are worth the extra $100 in flow.
Mopar Muscle magazine did some flow testing on the 906-346-452 heads and found only a 5% difference maximum between any of them in stock form. Once you back cut the valves and the ports are gasket matched the 452/346 out flow the 906 by a tiny bit (at street cam valve lifts of .509 and below, especially if you use a fast ramp cam like Comp XE, Lunati Voodoo, or Hughes) -- Anyway that's why I recommend the later ones because you never know when you'll want more power, and porting them is far easier (mainly due to the smaller valve guide bosses)
Yes, peak flow is about the same, but the sweet spot for a magnum/rv lift cam is stronger in the 906's stock.
And again, my advise was based on bolting them on as shipped from aerohead, if no plans to further enhance the heads, I believe the $100 premium for the 906's vs the later heads is worth it for a street car. <span class='smallblacktext'>[ Edited Thu Sep 16 2010, 08:54AM ]</span>
In that article he's comparing the mid-range flow of the 906 to the crappy 516's.
"from .300 thru .450 lift the 906 head averages between 15 and 20cfm better than the 516. This is a pretty big difference in flow, right in the range where the piston is pulling the intake charge into the cylinder."
I'd spend that extra $100 having them do a 70* plunge cut down the bowls to open them up in the later heads... anyway six of one, half a dozen of another!
Pretty soon it will cool off enough that I'll be able to bolt on the set of stage 2 ported 346 heads with huge valves (2.19"/ 1.88") I got from Lee Petty. They aren't "hogged out" so the port velocity is still good and will really help the flow at low-mid lifts. Since they were free, I had enough cash to have Hughes Engines in Tempe flow bench them- they flowed the same as a set of out of the box Edelbrocks. They suggested I a run a carbide cutter around the intake bowls to rough them up a little bit or else they might pool the fuel into big drops-apparently not good for a street engine where a rougher intake port is better at keeping the fuel mixture atomized. I'm also going to polish the chambers which really helps get rid of detonation.