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Aluminum heads over the 906s

Steve009

Steve009

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looking for opinions on possibly upgrading the heads on my 383. I currently have 906 heads from a 68 roadrunner. I was toying with the idea of a 440 swap but I already purchased and installed a bunch of parts for my 383 (eddy perf rpm intake, extreme energy cam, Holley DP, dougs headers, etc, etc) so I'd like to keep it. The 383 has a freshly rebuilt but stock bottom end so what heads would be the best swap where I could keep all these parts? Would the 75cc eddy e streets be the best simple swap? Fitting the intake and headers I already have would be nice and hoping for a bolt on out of the box swap. Any other suggestions? Would the 84cc be better?
 
Is this a 383 with positive piston deck height? That will determine which head will physically bolt on. A head swap would seem to be your next logical move. Maybe with some porting? What gearing do you have? What do you expect from this combo/car? Research what others are using too!
Mike
 
You can make the 906 heads produce good power. But it takes a lot of grinding to get there. The new modern heads will make more out of box. However every engine builder I've talked to has said all brands of HP aluminum heads need some work. A 75 CC aluminum head will produce more power. Aluminum heads have an effective CR of at least 1.0 less.
 
As 493mike said knowing the deck height and piston (flat top, domed or dished) is crucial on which head to go with. The 75cc could easily put you in the unfriendly zone not knowing what you currently have.

In my current motor with zero deck height and flat tops the 88cc 452 heads put me borderline. I can confirm it will ping on 87 octane but is fine on 92 or 93. Aluminum of coarse will help prevent that as well though.
 
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I have three mopar motors, two 440's and a 408 small block have aluminum edelbrock heads on all of them.....one 440 has the edelbrock ez street 75cc heads...they work great as long as you have flat top pistons in the motor. They actually raise the compression ratio from the 906 heads, which is great with aluminum heads. I have installed all my edelbrock heads straight out of the box with the exception of valve springs which may have to be changed depending on your cam selection. shop around for best price..I actually got my ez street heads from amazon...
 
flyingfarley said:
I have three mopar motors, two 440's and a 408 small block have aluminum edelbrock heads on all of them.....one 440 has the edelbrock ez street 75cc heads...they work great as long as you have flat top pistons in the motor. They actually raise the compression ratio from the 906 heads, which is great with aluminum heads. I have installed all my edelbrock heads straight out of the box with the exception of valve springs which may have to be changed depending on your cam selection. shop around for best price..I actually got my ez street heads from amazon...
Click to expand...
I haven`t built a 383, but I`d check out the trick flow 240`s if I were you.
 
from what I was told (I haven't seen the engine without heads) they are flat top pistons with 0 deck height. I don't think the 906s were ever ported and I was told the compression ratio is slightly over 10:1 (does that sound right for 906 heads with flat tops?)

this isn't a race car by any means but I do love hammering it around town. I have tall 29.5" cheater slicks, 4.10 gears, and a 4 speed so its definitely fun. I was thinking e-streets because I would assume it would be slightly better then the 906 flow and lighter. I honestly don't have the knowledge to be porting on my own. plus these e-streets seem really fairly priced. my main concern is drastically altering the compression ratio either too high or way to low. the cam going in for next summer is the Comp cams XE268H. I run Shell 91 octane so I don't think it will ping.
 
Don't run the Edelbrock 5090 E Street Heads - Speed Pro Forged Flat Top Pistons (No Valve Reliefs) - And the Mopar 284/484 Cam

Didn't work out as planned this past spring

All I did was swap the 906 heads that I installed on my 1971 383 magnum that was totally rebuilt about 25 years ago , Speed Pro pistons where about average .015 in the hole on the drivers side , never measured the passenger side when I took everything apart in Spring

Head gaskets the same at .039 on both sets of heads when I switched over

Man the car ran great before (.030 over , fully balanced ) but with those 906 heads I could shift all day long at 5500 rpms just by sound and feel as the motor stopped breathing - 3:91 Gears

Anyways those Edelbrock Heads loved RPMs , just smooth and noticeable increase all around performance for the week I ran them

Damn motor spun up to 6,000 RPMs very very quickly on a few occasions not paying attention when shifting manually with my Slapstik

Then the tick tick tick started at the gas station

Didn't even make it home 30 miles

Flat Tops with no valve reliefs = Bent pushrods = Wiped out cam lobe = Couple exhaust valves just barely and i mean barely kissing the pistons to the point my machine shop said the heads and valves where fine - Both valves that kissed where on the passenger side head of the motor

But it now has turned into a numbers matching 383 Stroker Motor that I still have not yet installed in my 1971 BEE

Bottom Line - Watch your piston to valve clearance especially if or close to zero deck with flat tops and no valve reliefs and any aftermarket cam , these Edelbrocks love to breathe along with the larger valves and porting over any factory stock head

Was a long summer without my car
 
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A good lesson. When you build a motor checking piston valve clearance correctly is required. Large cams need significant valve reliefs.
 
Also, most (all?) of the aluminum heads I have seen have larger than factory sized valves in them. This makes piston-valve clearance even more critical.
 
Bee1971 said:
Don't run the Edelbrock 5090 E Street Heads - Speed Pro Forged Flat Top Pistons (No Valve Reliefs) - And the Mopar 284/484 Cam

Didn't work out as planned this past spring

All I did was swap the 906 heads that I installed on my 1971 383 magnum that was totally rebuilt about 25 years ago , Speed Pro pistons where about average .015 in the hole on the drivers side , never measured the passenger side when I took everything apart in Spring

Head gaskets the same at .039 on both sets of heads when I switched over

Man the car ran great before (.030 over , fully balanced ) but with those 906 heads I could shift all day long at 5500 rpms just by sound and feel as the motor stopped breathing - 3:91 Gears

Anyways those Edelbrock Heads loved RPMs , just smooth and noticeable increase all around performance for the week I ran them

Damn motor spun up to 6,000 RPMs very very quickly on a few occasions not paying attention when shifting manually with my Slapstik

Then the tick tick tick started at the gas station

Didn't even make it home 30 miles

Flat Tops with no valve reliefs = Bent pushrods = Wiped out cam lobe = Couple exhaust valves just barely and i mean barely kissing the pistons to the point my machine shop said the heads and valves where fine - Both valves that kissed where on the passenger side head of the motor

But it now has turned into a numbers matching 383 Stroker Motor that I still have not yet installed in my 1971 BEE

Bottom Line - Watch your piston to valve clearance especially if or close to zero deck with flat tops and no valve reliefs and any aftermarket cam , these Edelbrocks love to breathe along with the larger valves and porting over any factory stock head

Was a long summer without my car
Click to expand...

thanks for this advice, this is the kind of thing I need to hear! It will make me more carful when choosing the heads. that stroker is going to be sweet, what combo did you use and what hp numbers do you expect to get?
 
Should be pointed out that OEM 6 Pak pistons had valve reliefs. If you plan on cutting the deck or heads and a larger than stock cam, proper depth valve reliefs are required. Keep in mind that minimum piston to valve clearance is NOT at max lift point. Need to check at the overlap points.
 
before the Trick flow heads came out, i bought bare 440 source heads for like 400$ each, then i sent them to Hughes engines for CNC porting and valves 1100$ then i got them home, and had my local guy double ck Hughes work, install and adjust the valve spring height, and mill heads to adjust and set final compression.

i have around 3k all in.

i think it was worth it.

even with out of the box heads there are imperfections. so if your ****, and want everything to be perfect this is the way to go.

that being said, i have Trick Flow heads on my race truck with a small block ford, and they were real damn nice for the money. all in around 1300$..for the Ford.
 
I should check some heads I have to see how far the valves can open before contacting a flat plate the head would be siting on. I have the original '71 '346 heads (all stock) from my 383, the new TF 240 heads, my old Victor MW heads, and my rebuilt B1 B/S heads (with 2.25" intakes.)
I don't have any RPM, eStreet, Indy, or Stealth heads heads to check. Anyone ever check this on any of these heads?
 
Keep in mind the piston is chasing the valve. Max camshaft lift is not nearly the point to consider. With larger camshafts the point of minimum clearance is far different than the max lift point on the cam.
 
mentor70 said:
before the Trick flow heads came out, i bought bare 440 source heads for like 400$ each, then i sent them to Hughes engines for CNC porting and valves 1100$ then i got them home, and had my local guy double ck Hughes work, install and adjust the valve spring height, and mill heads to adjust and set final compression.

i have around 3k all in.

i think it was worth it.

even with out of the box heads there are imperfections. so if your ****, and want everything to be perfect this is the way to go.

that being said, i have Trick Flow heads on my race truck with a small block ford, and they were real damn nice for the money. all in around 1300$..for the Ford.
Click to expand...

thats not a bad price $1300, i always thought trick flow were way more
 
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