440 BUILD TO 500 PLUS HP

[PlumCraZRT]

Counldnt you get pretty close to 500hp with the following:

Upgraded Cam

Alum Intake (Street Dom or Perf RPM)

850 Carb

Long Tube Headers (1-3/4 - 2in Primary)

If you start with a stockish 375 horse, 440 (906 or 915 heads) isnt it feisable that you could get close to 500 with just those added parts and no special head work?

Don

I'm sure you could do it, but you wouldn't have vacuum for the brakes/heater box.  With a decently streetable cam, I think you need some sort of headwork and/or a way to raise compression.  My 451 is eclipsing 500hp with aluminum heads (with bowl blend), aluminum intake, headers, 850 carb, and street-friendly custom Comp cam.

[Cooter]

So quickly we forget, the HEADS are where the power is...Bottom end is there for the torque factor.

So, yes, you could very well make 500 HP with a stock bottom end 440 with some cam, but it won't be a "Tame" one. COMPRESSION makes power. Today's fuel won't allow it though.
You state beginning with a 375 HP MAgnum. That would be great if it actually produced the total 375 HP. More likely 350 HP in bone stock form.

[The Cuda Guy]

Im tracking that the heads make the power ect.  Just thought it would be less hassel and get you close to the goal of 500hp with out removing the heads.  That is all.

I would guess that about 50% of them members would not want to tackle removing the heads off their mopar.  So they would have to get a buddy or pay to get that type of work done....  Just a guess so I figured I ask as the bolt ons and the cam install seem easier than pulling the whole top end off. 

But for the money you cant beat a set of regular stealth heads ($995.00pr), just have your machinist look them over before installing them.

Don

[351c4v71]

I have 906 heads and just saw some 516 heads for sale near me at 150$.
They'll have to be machined and all but should I buy these?
Will they fit my present headers?
How much hp can one expect to gain when comparing 516 to 906.
How much does it typically cost to have a bare bone 516 head machined and ready to go (springs, cam , retainers, etc)

I'm just looking anywhere to increase hp at a low cost.

[PlumCraZRT]

I have 906 heads and just saw some 516 heads for sale near me at 150$.
They'll have to be machined and all but should I buy these?
Will they fit my present headers?
How much hp can one expect to gain when comparing 516 to 906.
How much does it typically cost to have a bare bone 516 head machined and ready to go (springs, cam , retainers, etc)

I'm just looking anywhere to increase hp at a low cost.

For $150, I would pull the trigger.  Assuming the heads haven't been milled too much (ie the chamber is still large enough), you should be able to build the bottom end up nicely to support these.  Are you working from scratch on the bottom end or are you building from a stock/known bottom end?

The reason I ask is that you will want to get compression as high as possible while utilizing quench to prevent detonation.

[351c4v71]

I'm working from an engine that's already working fine. 440 6 pack set-up. I would only change the heads, valves, cam, springs.
Keep the 6 pack set-up carbs and intake and headers.
But is it worth changing 906 for 516? Are we talking 1000$ total  for 30hp gain?
or 600$ for 50hp gain.
My cam now is a 270h comp cam with 6 pack pistons. Don't know much else about this engine.

[PlumCraZRT]

I'm working from an engine that's already working fine. 440 6 pack set-up. I would only change the heads, valves, cam, springs.
Keep the 6 pack set-up carbs and intake and headers.
But is it worth changing 906 for 516? Are we talking 1000$ total  for 30hp gain?
or 600$ for 50hp gain.
My cam now is a 270h comp cam with 6 pack pistons. Don't know much else about this engine.

Assuming you know how far in the hole the pistons are (and what the bore diameter is), working the heads (to get good compression/quench) and swapping the cam should get you into 500hp territory.  As Chryco will tell you, there are far better cams for Mopars than the off-the-shelf Comp profiles.

[351c4v71]

Just re-read Chryco's post.
So 1500-1600$ total plus 150$ for the heads in my case to get about 500hp compared to maybe 420hp that I guesstimate I have.
That's about 22$ per hp.
Thanks guys

[PlumCraZRT]

Just re-read Chryco's post.
So 1500-1600$ total plus 150$ for the heads in my case to get about 500hp compared to maybe 420hp that I guesstimate I have.
That's about 22$ per hp.
Thanks guys

My guess is that 420hp is a gross over-estimate...

[Moparal]

I saw on Ebay an NOS set of stock 516 heads , still in the original boxes for 200 buy now, if you found the site, you could transfer all your existing valves and springs over to them with low costs, if the stuff you have is good.  I would look for some good 915 heads myself, if you were going to use production heads, they will actually flow better by a few more cfm's from all I have ever gathered.. If I read right., A 270 comp cam isn't a good choice for trying to build 500 hp. As mentioned, there are better cam choices out there.

[PlumCraZRT]

I saw on Ebay an NOS set of stock 516 heads , still in the original boxes for 200 buy now, if you found the site, you could transfer all your existing valves and springs over to them with low costs, if the stuff you have is good.  I would look for some good 915 heads myself, if you were going to use production heads, they will actually flow better by a few more cfm's from all I have ever gathered.. If I read right., A 270 comp cam isn't a good choice for trying to build 500 hp. As mentioned, there are better cam choices out there.

Agreed, the 915 heads are better since they have a larger 2.08" intake valve and either the 516's 1.60" or the "magnum" 1.74" exhaust valve.

[Chryco Psycho]

Well I would say go for it , the 906 can be sold , installing hard seats & 1.81 exhuast valves is relatively easy , do some port matching & you have a quench head which will help kill detonation , you can keep a budget & imporve the overall package

[The Cuda Guy]

Ok, if we are down to hp per dollar, spending 1500 on iron heads is not going to get you the bang for the buck that a set of stealth heads will get you.  You will prob spend 1500 total on a set of stealths after you get them checked out and cleaned up and you have everything right there, 2.14int and 1.81ex, and a head that flows far better then any factory 440 casting.  This would be your best choice. IMO.

Don

[351c4v71]

Just found out my block is not a 70-71 but rather a 73-74 
And read those blocks have a much lower compression ratio. So I guess my hp is way lower then expected.
Was it the pistons or the deck height that changed to reduce compression in those days?
If I want to increase compression, besides shaving the heads, can I shave the deck?
This engine was rebuilt totally 5 years ago and I don'T know what went in it. So compression is unknown right now...
I just have an invoice from previous owner that says 270h comp cam and 6 pack pistons.

[GranCuda1970]

Go to 440 source and get all the guts you need to make her a HP monsta!!! They have pretty good pricing and I was tempted to git some stuff until I bought the crate.