72' imperial 440 to 71' HP spec

[A38E86D32]

Hey guys,
My 71' troop car lost it's original 440HP engine long ago. It's since been replaced by a 72' imperial 440. The engine runs OK, just doesn't have the grunt I'm told the original mill had. Even though it's not the correct dated block, I'd like to build it to 71' HP spec. I'm thinking only changes needed are:
Bump compression up with new piston and rings to around 9.5:1
Try to find a 71 HP cam or maybe swap in a mopar restoration cam.
I believe the heads (346), intake, crank, and rods would be the same.
Basically i want the engine to be like the original in performance and sound.

Let me know your thoughts, guys.

 

[commando1]

The '71 was dialed back a tad because of emissions. You may want to consider the 69 specs.

 

[A38E86D32]

10.5:1 compression for 69 and better cam?

 

[commando1]

10.5:1 compression for 69 and better cam?

My memory on researching the specifics for the 440s from aprox 67-71, what I considered the peak years, is spotty.
I do remember that I looked at all the cams in all the versions (picture my head exploding) and the torque curve of the 69 HP was a monster. Ideal for 5,000 lb. C-bodies in my opinion.
I would dial back the C.R. though. Today's crappy gas can't cut it.

 

[A38E86D32]

Torque is king for these monsters!

 

[BigFury]

You could do a stock '72 short block with a little bowl work on your heads with a good valve job and a mild cam and it'll work real good. 9.1 is max on the "gas" we have today.

 

[Turboomni]

How much higher could he go on his CR if he installed aluminum heads on pump gas? He most likely wants the stock look but I was just curious.

 

[commando1]

How much higher could he go on his CR if he installed aluminum heads on pump gas? He most likely wants the stock look but I was just curious.

I insist it's negligible.
The less informed who rely on glossy magazines will say you can go up another pt. with aluminum.

 

[Turboomni]

That is why I asked ,,because I thought that was the case with aluminum heads..but I guess not. With my little Omni glhs turbo I used methanol /water injection to keep stuff from blowing up.

 

[commando1]

That is why I asked ,,because I thought that was the case with aluminum heads..but I guess not. With my little Omni glhs turbo I used methanol /water injection to keep stuff from blowing up.

BMW is introducing water injection into their new cars and the auto press is going all silly ga-ga all over this. WTF?? Are all these auto writers 25 years old or something? We were making our own home made setups back in the sixties. J, C, Whitney had water injection systems for petesakes...

 

[Big_John]

BMW is introducing water injection into their new cars and the auto press is going all silly ga-ga all over this. WTF?? Are all these auto writers 25 years old or something? We were making our own home made setups back in the sixties. J, C, Whitney had water injection systems for petesakes...

62-63 Olds Turbo Jetfire had a water/alcohol injection system.

 

[Turboomni]

62-63 Olds Turbo Jetfire had a water/alcohol injection system.

Yes indeed it did and before that WW2 fighters used water and alc injection to compensate for poor fuel during the war so not to blow up engines and lose a pilot and or plane. With the Olds you would buy from them a solution to put in a bottle under the hood. Boost pressure then was controlled by a restrictive exhaust as well as the BMW 2002 turbo but to my knowledge BMW did not require water injection at the time. Exhaust must have been very restrictive.

 

[Turboomni]

Quote:::::Are all these auto writers 25 years old or something? Quote


yup at least that...
If BMW is offering water injection on some cars I hope the tank is at least 25 gallons as no one these days checks anything unless it doesn't move....

 

[CanCritter]

lm at 10.5 with iron...would feel quite comfortable with alum and 11.5

 

[barnfind]

62-3 olds, Had a 63 f 85 conv, no turbo thou. 1st car I ever fully restored, was part of a chicken coop when I found it. The Aspen was a wreck that I put back together, The Maverick got totaled out.

 

[commando1]

"Turbo Rocket Fluid"...
lol

 

[Turboomni]

lm at 10.5 with iron...would feel quite comfortable with alum and 11.5

Is that on pump 93 ?

 

[70bigblockdodge]

Here is my take on aluminum heads and compression ratios.
Most/all aluminum heads are closed chamber design with heart shaped or or quench areas filled in to create air movement when the piston approaches tdc, moving air/charge resist exploding (detonation) better than dead air in a big open chamber like 906, 346, 452 big block heads. The manufacturers started to figure this out in the eighties with high swirl, vortex, etc.. This is why aluminum heads resist detonation better the swirl or turbulence rather than the small heat transfer advantage.

 

[commando1]

This is why aluminum heads resist detonation better the swirl or turbulence rather than the small heat transfer advantage.

What I've been saying.
Iron heads with with the same combustion chamber design of the aluminum heads would make all things equal.
Better actually. No Helicoils.

 

[70bigblockdodge]

What I've been saying.
Iron heads with with the same combustion chamber design of the aluminum heads would make all things equal.
Better actually. No Helicoils.

Port size and quality of the foundry work also comes into play power wise