Replacement for displacement?

jeepthrills01

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Ok...thoughts? Which will make more power? Smiles per gallon!

The 440. Bone stock 35000 mile 1978 RV smog motor with these addons:
Eddy heads with fresh valve job, chambers cut to 79cc (pistons at .150 down), .027 head gaskets. Lunati 702 (228 duration .475/.495 lift at .5) hydraulic cam, 1.6 roller rockers, Performer RPM , 800 cfm AVS2 or a Fitech 600hp capable system.

The 383 picked up freshly rebuilt (albeit 25 years ago, came from storage). Same heads/gaskets/cam/rockers/carb or efi will go onto the choice engine. Also have Performer RPM for 383.
12cc dished pistons but only at .007 down.

69 coronet HT, 727, 2800 9" converter, 3.23 or 3.73 gears with 28" tires.
I have my ideas, just looking for popular opinion if these were the parts you had...which one gets the nod.
Thanks gents.
 

DeltaV

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The one that breathes the best. :)


Compression ratio is what on each? Curiosity.
 

jeepthrills01

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IQ52 would agree....but its very close with the shared parts

Same carb/intake/heads/headers/cam
 

kramer

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Use the 440 and go with the 800 AVS, simple setup and make some good streetable power.
 

jeepthrills01

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Just from my calculations...
The 440 will be about 7.75:1CR

The 383 will be about 9.7:1CR desktop dyno was coming up with 450tq @ 2100..stays above 390 to 5800 rpm. Roughly 440 HP at 6100

I didnt run the 440..just thinking to IQ52s posts.

Same flow (cause same heads/intake etc).
 

SlinktRR

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I got 9:1 cr for the 383 with the dish. I would run the 383 with a different cam, I would prefer revving a 383 with decent compression vs a motorhome 440.
 

kramer

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Compression ratio will be closer to 8.5 to 1 and will most likely run very well on low octane fuel with a well dialed in ignition timing. Should have very good low end torque and be able to run a taller gear ratio without being a slouch on the low end.
 

jeepthrills01

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I mistyped...heads are 70 cc.
Sorry lads

And side note..Slink..that cam makes power through 6500.js
 

jeepthrills01

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I think you need a new calc kramer.

Screenshot_20230124-235043_Chrome.jpg


Screenshot_20230124-235101_Chrome.jpg
 
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RemCharger

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I've had a similar 440, low 12s in a car, and 12.50s in a truck.
So what are you putting this into?
 

jeepthrills01

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I've had a similar 440, low 12s in a car, and 12.50s in a truck.
So what are you
69 coronet HT, 727, 2800 9" converter, 3.23 or 3.73 gears with 28" tires.
I have my ideas, just looking for popular opinion if these were the parts you had...which one gets the nod.
Thanks gents.
Quoted from post 1
 

Kern Dog

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How far do you have to mill Edelbrock heads to get them from 84 ccs down to 70 ???
 

Kern Dog

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That won't do it. You're talking 14 ccs. Your math is flawed.
 
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