Replacement for displacement?

[MarPar]

 

[Master Gunner]

I come up with about .100, and then you'd have to take about .123 off the intake side (.0123 for every .010), or the intake will never seal.

Mark

 

[RemCharger]

Quoted from post 1

Argh missed that, almost like it didn't show up..
I'd go with the 440. And this is coming from a dyed in the wool 383 guy.
If you had 70 cc heads, I can't see it being 7.7:1.
That's what they had with the 90cc heads.

 

[jeepthrills01]

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

In an open chambered head I would agree with you. The closed chamber gets smaller as you cut.
I measured 83cc before machining. 70.3cc after.

Closed chamber heads are roughly .05 per CC.

 

[6PKRTSE]

For just drop in and go. I would go with the 383. Most people don't give the 383 the respect they deserve. I have had several 383's than ran pretty spicy. Enjoy the 383 and build a stroker out of the 440 over time.

 

[jeepthrills01]

For just drop in and go. I would go with the 383. Most people don't give the 383 the respect they deserve. I have had several 383's than ran pretty spicy. Enjoy the 383 and build a stroker out of the 440 over time.

Kinda what I was thinking....Ill be able to afford the TF heads then too

 

[Geoff 2]

I have milled factory heads 0.120" to use on a 426 wedge, to increase CR from the 7s. It made veeeeery little difference to the performance.

Comparing a lower compression 440 to a 383 is a cheese/chalk comparison. The increase in cubes is 15%, which is roughly what the tq increase will be. A point or two of compression in a 383 might add 5% with a tail wind.

 

[1STMP]

I come up with about .100, and then you'd have to take about .123 off the intake side (.0123 for every .010), or the intake will never seal.

Mark

Not to be a stick in the mud, but my
stock heads were milled .010 to
straighen them up. I installed the Eddie
Performer with the stock 2 gasket/
valley pan with zero vacuum leaks.
Would this be a rare occurrence?
This is on a '68 block with 452's,
and the performer right out of the
box.

 

[Master Gunner]

A .010 cleanup cut would "probably" not be much of an issue. The problem is when the block is decked to clean and square it, and then the heads are cut to bring up the comp, so betwen the two of them you're at .050 or more and that can be a problem.

Mark

 

[4speed68rt]

440 all the way. Lower compression is good, so you can run cheaper gas. Then you can sell that 383 and never look back. 57 is alot of cubic inches of advantage to start with, then with all of the new stuff that you will wind up putting on it anyways, you will be headed the right direction.

 

[jeepthrills01]

440 all the way. Lower compression is good, so you can run cheaper gas. Then you can sell that 383 and never look back. 57 is alot of cubic inches of advantage to start with, then with all of the new stuff that you will wind up putting on it anyways, you will be headed the right direction.

Another valid point...but temptation for the HP in a bottle will be high!

 

[jeepthrills01]

I have milled factory heads 0.120" to use on a 426 wedge, to increase CR from the 7s. It made veeeeery little difference to the performance.

Comparing a lower compression 440 to a 383 is a cheese/chalk comparison. The increase in cubes is 15%, which is roughly what the tq increase will be. A point or two of compression in a 383 might add 5% with a tail wind.

With no other changes I see why you were less than satisfied. But changing to a cam/ intake and carb that can use that increased compression effectively can really wake things up. You have to consider the entire package.

 

[33 IMP]

I'd put pistons in the 440, and run that. Or, a stroker .

 

[Geoff 2]

Post #32. Huh? You can also add cam/intake/carb to the 440....

 

[INTMD8]

Replacement for displacement is high rpm and gearing to match. Doesn't apply here really, gets expensive quick and is less friendly at lower rpm.

To answer the question, if those were the parts I had, I would use none as-is.

Would sell the 383 to help finance building the 440 how I wanted it.

Cut down the heads for a 45 year old low compression engine, pistons down a mile and carrying 5/64 rings? I would not.

At the very least I would replace the pistons with the desired compression height and a modern ring pack along with proper bore/hone.

JMO

 

[jeepthrills01]

Post #32. Huh? You can also add cam/intake/carb to the 440....

Did you read post #1?

 

[jeepthrills01]

Im guessing there was not enough clarity..so here again is the basic parts list.

35k mile smog 440 short block, flat top pistons .017 in the hole

Older rebuilt never fired and stored 68 383 short block with 12cc dished (2bbl) pistons .007 in the hole.

1 set of fresh Eddy heads with 70cc chambers

Cometic custom .028 head gaskets (4.35" for 383/ 4.45" for 440)

Performer RPM 440
Performer RPM 383
Heddman headers
Lunati 702 big block cam
1.6 Roller Rockers
Eddy 800 AVS2
Fitech 600hp capable EFI (and supporting fuel system)

Pick your parts for most smiles pergallon with 4 trips to the track a year...and cruising/bragging on the weekends.

 

[33 IMP]

Im guessing there was not enough clarity..so here again is the basic parts list.

35k mile smog 440 short block, flat top pistons .017 in the hole

Older rebuilt never fired and stored 68 383 with 12cc dished (2bbl) pistons .007 in the hole.

1 set of fresh Eddy heads with 70cc chambers

Cometic custom .028 head gaskets (4.35" for 383/ 4.45" for 440)

Performer RPM 440
Performer RPM 383
Heddman headers
Lunati 702 big block cam
1.6 Roller Rockers
Eddy 800 AVS2
Fitech 600hp capable EFI (and supporting fuel system)

Pick your parts for most smiles pergallon with 4 trips to the track a year...and cruising/bragging on the weekends.

440 pistons .017 in the hole..... or .170?

 

[jeepthrills01]

440 pistons .017 in the hole..... or .170?

Fast typing fat fingered..lol

.170. Lol

 

[jeepthrills01]

I'd put pistons in the 440, and run that. Or, a stroker .

These are the parts....pick from whats here