Then somebody knew absolutely nothing about what they were doing.
Big Block Cylinder Heads "915 vs 906"
- Thread starter 69 Cuda 440
- Start date
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Then somebody knew absolutely nothing about what they were doing.
Because the cost to prep the heads varies greatly depending on location. I can get the big valves installed and them ported for price good enough to avoid having to buy aluminum heads. Plus, I have worked with my machine shop and my head porter such a good bit, that they will both let me pay in increments until the job is finished. Not everybody has 1500 or more dollars to throw out all at once.
txstang84
Well-Known Member
True story...even if you're buying the $1000 Stealth heads, it's been made pretty clear on these forums, bolting on a set of new aluminum heads without cleaning up the bowls and seats, a quick surface cut to ensure straight decks, plus checking installed heights on the springs is borderline negligent. Those processes, where I was at before, would be worth about another $350 for a complete set of V8 heads.
Correct,
One of our customers bought a set of Edelbrock RPM 440 Performer Cylinder Heads for $1400.
He thought he could just bolt them on the 440 Short Block we built for him, 'right-out-of-the-box'.
'No Way Jose'
906 heads suck, here is one our experiments, ported with no epoxy or welding. Haven't been able to get the 915s to make as much flow as the 906s, water passages are different. I guess the 915s really suck.
451ci/400 block, 9.7:1 compression, 91 octane, single 4150 4bbl, single plane intake, Erson solid roller that was too big, but what the heck, it was laying on the shelf. I couldn't afford the $330 to have a new one ground correctly.
At the time, the dyno couldn't hold the engine below 3300 rpm.
RPM.............TQ/HP
3300...........442/278
3800...........485/351
4300...........506/414
4800...........518/474
5300...........508/512
5800...........536/592
6300...........548/658 peak torque
6800...........531/688
6900...........528/694 peak horsepower
7200...........499/684
Rotten weeny, it didn't even make 700 HP.
451ci/400 block, 9.7:1 compression, 91 octane, single 4150 4bbl, single plane intake, Erson solid roller that was too big, but what the heck, it was laying on the shelf. I couldn't afford the $330 to have a new one ground correctly.
At the time, the dyno couldn't hold the engine below 3300 rpm.
RPM.............TQ/HP
3300...........442/278
3800...........485/351
4300...........506/414
4800...........518/474
5300...........508/512
5800...........536/592
6300...........548/658 peak torque
6800...........531/688
6900...........528/694 peak horsepower
7200...........499/684
Rotten weeny, it didn't even make 700 HP.
Yes, and sometimes they require more than that. Even the best aluminum heads need to be checked out and will likely need something. In stark contrast, I can go find a clean pair of heads in a salvage yard, take them home, clean them myself, check them for cracks myself and if I really luck out the guides and seats are still good. I can do a basic valve job myself pick some springs out and run them. People talk about how crappy the factory did stuff, but that seems to be hard to duplicate in the aftermarket, doesn't it?
Yeah. I reckon my friend really bent me over when he gave my these 906s the other day. That bastard. lol
Great numbers, IQ! As for Eddy's OOTB, not worth installation without a tune up.
80fbody
Well-Known Member
Wow, I'm working on a 451 now for a really light dart. Was told it should be under 2500lbs with BB. I've got some 346 heads that were home ported years ago then sat on the shelf till now. What's it cost to get a set to flow well & including installing larger valves? I think it would be great to knock out some really low 10's with a stock crank, rods & iron heads. Thoughts?
It is not worth porting iron heads for really big horsepower unless you must use the iron heads because of the rules. In your case, if you can get the car to 2500lbs, the 346 headwork w/valves would cost about $1500. If the rest of the engine is right they could get you 620+hp. But we're really behind right now, ask the overly patient SGBARRACUDA.
80fbody
Well-Known Member
Gotcha. Thanks.
"915 vs. 906"
In flow numbers, has anybody found any great difference in Intake CFM.
Stock vs. Stock, we found them nearly 'identical', with the slightest-edge for
the '906' above .400"
In flow numbers, has anybody found any great difference in Intake CFM.
Stock vs. Stock, we found them nearly 'identical', with the slightest-edge for
the '906' above .400"
I "heard" and seen ,a late 67 915 casting. Had a better "short radius",than normal 915 castings.69Cuda440, any knowledge of this? It did have a wider floor,and a taller roof....
EL5DEMON340
Well-Known Member
That's what I have always seen very slight flow edge to 906, but the close chamber with the increase CR and posible quench if set up correctly far and away makes it a better head! I've sold two bare sets in the last few years both sold for $300. Even the 516 on a MILD 383 in need of compression is better than a 906.
I never compared 'early "915" 440 HiPo Heads to any later "915" 440 HiPo Castings.
I usually found all the 915's........ at 195-197 CFM @ .450" Lift.
What did the later Castings flow at...???
That,I don't know. Just a core head,from 1987 I saw. Was called supposedly"1967 CHP 440 head".Was unprted,It did have,a taller roof,and a more stable short side.
A possibility....
I wonder if Chrysler 're-cast' the later #915 Cylinder Heads 'replacement heads' with a revised Port Design.
From back in the early 1970's Direct Connection catalog.
I believe that is where they were called the '40 Horsepower Heads'.
The 67 915 was not the only 915. There was a 915 that had the small 1.6 exhaust valve, too. Now whether the ports were the same, I have no clue.
The #915 Cylinder Heads with the 1.60" Exhaust Valves had nearly
the same Port Sizes {claim of identical}, but the Exhaust Valve 'bowl
area' below the Valve Seat was smaller.
The Exhaust Ports on the 1.60" Exhaust Valve Heads flow at
approximately 20 CFM's less than the 1.74" Exhaust Valve Heads.
The Intakes are 'near identical'.
That makes sense. Thanks. It wouldda been stupid I think for the two heads sharing the same casting number to be vastly different.
roccodart440
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Here we go again, you love those stock heads? I know, with those huge valves and huge flow numbers, who wouldn't?
I think if you knew my engine builder you'd think otherwise.
So the engine builders that cut 50+ sets of heads in half to learn to port them and still require epoxy or brazing know nothing. Come on... If you go big with these heads they often need epoxy and it differs from one to the other due to core shift and production tolerances. There is a big time engine builder who posts over the bbd.com and I've read his threads on using stock heads and high hp builds for contests etc. I've also built 3 440's.
I know, I know you can make insane power with stock heads... With what compression, heads and cam and how streetable is it?
Bottom line for what it cost to go big with stock heads (porting, vlaves, replacement parts, machine labor..) i'll take an aftermarket aluminum head all day long for more reasons than just flow
Everything depends on the application.
If you're building a 'restoration car' or 'general street performer', you can
make a set of 'stock' #915 or #906 Heads work fine, with a little massaging.
If you have an 'extra $1500, a set of Edelbrock Performer RPM's will do the trick.
With some 'nifty' Seat Angles, and just minor porting and bowl area smoothing,
the 'stock' Cylinder Heads work fine on the street.
We've got a customer with a 440 in a Duster, that runs 10.30's with #915 Heads
and 2.08" and 1.74" Valves, and the car on occasion, is 'Street Driven'.
He's one 'Happy Camper'.
If you're building a 'restoration car' or 'general street performer', you can
make a set of 'stock' #915 or #906 Heads work fine, with a little massaging.
If you have an 'extra $1500, a set of Edelbrock Performer RPM's will do the trick.
With some 'nifty' Seat Angles, and just minor porting and bowl area smoothing,
the 'stock' Cylinder Heads work fine on the street.
We've got a customer with a 440 in a Duster, that runs 10.30's with #915 Heads
and 2.08" and 1.74" Valves, and the car on occasion, is 'Street Driven'.
He's one 'Happy Camper'.
txstang84
Well-Known Member
Well, now that sucks--the 915s I have in my storage unit back in Texas are small exhaust versions. I honestly figured I could open them up to 1.74" exhaust and make back the difference with some mild bowl work.
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