1965 MOPAR 383HP 4bbl Flat Pistons vs 1968 MOPAR 383HP 4bbl Flat Pistons Compression Height

[Mopar2488]

Is 65 383HP 4bbl Flat Pistons Compression Height same as 68 383HP 4bbl Flat Pistons CH of 1.932" vs 1.934" or are they different Compression Height. My Block Number 2468130 Date Aug 8 64

Thanks

 

[pnora]

As far as I know the 63 was a part number 187933. That number was superseded several times to the 68 part number 3004531.

OE Cross Reference: 1879333, 2525433, 3004524, 3004531, 3420210, 3420206

 

[Lefty71]

Not to interrupt....someone help with my ignorance... what is a 1965 383hp?? Police engine??

 

[Mopar2488]

Not to interrupt....someone help with my ignorance... what is a 1965 383hp?? Police engine??

I know about my 65 383 block is stamp on ID pad HP, called High-Performance 4bbl like below, this engine was already installed in 68 Charger when I brought car from my uncle, my uncle was original owner of that 68 Charger.

 

[Dave6T4]

Compression height on '68 piston would be higher than '65 to make up for larger combustion chamber on '68 "906" heads. Both '65 and '68 383 motors were 10 : 1 compression. This was done by juggling piston compression height around. '68 pistons in your '65 engine with '65 heads would raise your compression up pretty well a full point (11 : 1). For street use, this would be incompatible with today's fuel.

 

[Dave6T4]

Not to interrupt....someone help with my ignorance... what is a 1965 383hp?? Police engine??

Four barrel and slightly hotter cam than also available 383 two barrel.

 

[Mopar2488]

Compression height on '68 piston would be higher than '65 to make up for larger combustion chamber on '68 "906" heads. Both '65 and '68 383 motors were 10 : 1 compression. This was done by juggling piston compression height around. '68 pistons in your '65 engine with '65 heads would raise your compression up pretty well a full point (11 : 1). For street use, this would be incompatible with today's fuel.

Hey Dave6T4
Do you know Compression Height for '65 383 Piston because my uncle told me only camshaft has change and everything else is stock except it has 68 exhaust manifolds to fit my exhaust pipes

 

[1 Wild R/T]

 

[Mopar2488]

Thanks for the help

 

[sabre67]

 

[Jerry Hall]

I don't know the compression height of either year piston. Nor do I know what heads your 65 engine is running. I am only assuming that the 67 and prior 383's were closed chamber heads. In 68 the heads on a 383 went to open chamber 906's, therfore to keep the same compression ratio the compression height was changed to maintain the 10 to 1 advertised compression.
I didn't figure actual compression ratio on my 67 383 4bbl engine that went back together with original stock pistons and 516 closed chamber heads, but the pistons are 16 thousandths in the hole.

 

[mopar 3 B]

I don't know the compression height of either year piston. Nor do I know what heads your 65 engine is running. I am only assuming that the 67 and prior 383's were closed chamber heads. In 68 the heads on a 383 went to open chamber 906's, therfore to keep the same compression ratio the compression height was changed to maintain the 10 to 1 advertised compression.
I didn't figure actual compression ratio on my 67 383 4bbl engine that went back together with original stock pistons and 516 closed chamber heads, but the pistons are 16 thousandths in the hole. View attachment 1333902

That sounds about right with the factory metal gasket. Just don't use 516 heads on a 68 block without checking piston deck height. If need be, a thicker head gasket will give the required clearance.

 

[Mopar2488]

My Cylinder heads are original 64-67 516 with original pistons in ‘65 block

 

[Jerry Hall]

That sounds about right with the factory metal gasket. Just don't use 516 heads on a 68 block without checking piston deck height. If need be, a thicker head gasket will give the required clearance.

A common swap in the day on stock 68-70 engines was to switch to 67 and prior closed chamber heads. As long as the engine was stock otherwise there wasn't a problem. I understand with cam swaps with increased valve lift one can get into trouble real easy.

 

[Geoff 2]

My Sealed Power catalog lists four compression hts for the 383: some are forged, others cast
- 70-71 2bbl 1.868
- 68-71 4bbl, 68-69 2bbl 1.934"
- 1 57/64"
- 59-64 all; 65-67 with prem fuel 1.890"

 

[1 Wild R/T]

My Sealed Power catalog lists four compression hts for the 383: some are forged, others cast
- 70-71 2bbl 1.868
- 68-71 4bbl, 68-69 2bbl 1.934"
- 1 57/64"
- 59-64 all; 65-67 with prem fuel 1.890"

1 57/64 = 1.890

 

[33 IMP]

I think there was confusion between hp-high performance
and hp-horsepower.

 

[mopar 3 B]

I think there was confusion between hp-high performance
and hp-horsepower.

What? High performance is a relatively new term in the automotive world.