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Trying to increase HP in 440

Avalanche

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I have a 1978 warranty motor in my challenger approx 2000 miles on it. It has stock exhaust manifolds, 906 heads, stock intake and a holley 770 street avenger with vacuum secondaries.
I'm trying to increase horsepower without rebuilding motor.
Any ideas?
 
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moper

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As far as bolt ons - the best bang for the buck would be headers and a decent free flowing exhaust. These will add power and economy even on stock engines. Next would be a camshaft and valve springs swap. An easy project with minimal tools that can totally change the character of the engine.
 

Avalanche

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As far as bolt ons - the best bang for the buck would be headers and a decent free flowing exhaust. These will add power and economy even on stock engines. Next would be a camshaft and valve springs swap. An easy project with minimal tools that can totally change the character of the engine.

What cam would work best?
Would swapping the 906 heads be worth the money?
And would the engine need to be balanced again?
 

js29

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I am more bodyman than mechanic but after talking to summit tech the cam and intake are matched too ware you want your power band do you want low end -mid -or top end. aluminum heads work better on nigher compression engines and pump gas. and as for balance go's as long as the rotating assembly is not changed it should not be affected you also need to consider a converter if you have an automatic transmission hope this help's
 

moper

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What cam would work best?
Cams are al lover the place. Different people like different stuff. As for myself - I like either Comp or Crane product due to cost, quality, and ease of installation. There are les expensive options - the Summit line of camshafts is actually really good - and good value. I'd avoid MP due to lose quality control. As far as recommendations: keep the size relatively small - duration at .050 around 220° and lift anywhere up to .500 or less. The Summit "large" cam, or the Comp XE268 would be great fits and require no head machining for the springs they require. If you don;t own one - buy a degree wheel or degreing kit. Any cam you install will benefit from degreeing it. Also plan to replace the timing set and valve springs.
Would swapping the 906 heads be worth the money?
My own opinion is if it runs well now, then no. You're nowhere near exhausting the potential of a stock head, nor even getting into where spending on heads will give you benefit. So at this point - no.
And would the engine need to be balanced again?
Not unless you replace the pistons. If you go that route then a whole different recipe would be advised.
 
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