Piston recommendations

[Dimension]

I am just starting to look at parts for my '69 Road Runner 383 with 906 heads. I currently have a Torker 383 intake that I want to mount on top of it. I would like to use the Comp Cam XE285HL with the stock 906 heads is possible. I know that the cam states that it wants 10:1 compression so I am trying to see what I need to do as far as piston wise to get close to 10:1 compression if I keep the stock heads. I am basically recreating Hot Rod's 383 restro to rad article but would like to up the compression to 10:1 to help out the cam while still trying to keep as many stock parts as possible.

Any suggestions on how to accomplish this?

 

[joe smith]

I am just starting to look at parts for my '69 Road Runner 383 with 906 heads. I currently have a Torker 383 intake that I want to mount on top of it. I would like to use the Comp Cam XE285HL with the stock 906 heads is possible. I know that the cam states that it wants 10:1 compression so I am trying to see what I need to do as far as piston wise to get the as close to 10:1 compression if I keep the stock heads. I am basically recreating Hot Rod's 383 restro to rad article but would like to up the compression to 10:1 to help out the cam while still trying to keep as many stock parts as possible.

Any suggestions on how to accomplish this?

Modern pump fuel with iron heads does NOT like 10-1 compression or higher...

 

[Dimension]

OK so 10:1 is out, what is my best option? Running higher than pump fuel is possible for I live near a major race track.

 

[IQ52]

Do you realize you will not be able to use the factory 906 heads without some machine work?

 

[Dimension]

Do you realize you will not be able to use the factory 906 heads without some machine work?

In order to achieve the 10:1 compression or with the cam? I know that the cam requires double springs to work with the heads.

 

[Dimension]

From what it is looking like from the couple of responses I have gotten 10:1 is out so I will have to stick with stock pistons.

 

[IQ52]

The cylinder heads will need the spring pockets and the guides machined to work with the cam. I have successfully used the XE285HL at 8.9:1 in a 440 with 346 factory iron heads.

 

[IQ52]

I do not know what pistons you are currently running in your 383. Piston to valve clearance may become a factor also.

 

[Dimension]

The cylinder heads will need the spring pockets and the guides machined to work with the cam. I have successfully used the XE285HL at 8.9:1 in a 440 with 346 factory iron heads.

Thanks, I was planning on buying all my parts and then taking them all to the machine shop so that they can machine and do what they need to do with parts in hand instead of doing a generic machining. I was wanting them to machine each piston hole to the piston.

 

[Dimension]

I do not know what pistons you are currently running in your 383. Piston to valve clearance may become a factor also.

Everything is factory right now as it came in '69.

 

[Jerry Hall]

Thanks, I was planning on buying all my parts and then taking them all to the machine shop so that they can machine and do what they need to do with parts in hand instead of doing a generic machining. I was wanting them to machine each piston hole to the piston.

Go to the machine shop and let them offer some advice. A reputable shop will know what works with what. You know what cam and heads you want to use, I'm sure they can make recommendations.

 

[Outsider]

To the specific original question about pistons, how about something like the Keith Black series KB162-020, or what ever over bore you need. I run the comparable in my 400 build, resulting in about 9.5 comp, with plenty of valve clearance. I have an old design Purple Shaft cam with the similar duration. Pistons working well, but sometimes wish I put a different cam in it something like a Lunati Voodoo 10230702.

 

[Dimension]

To the specific original question about pistons, how about something like the Keith Black series KB162-020, or what ever over bore you need. I run the comparable in my 400 build, resulting in about 9.5 comp, with plenty of valve clearance. I have an old design Purple Shaft cam with the similar duration. Pistons working well, but sometimes wish I put a different cam in it something like a Lunati Voodoo 10230702.

Why the different cam? What is it you do not like about the one you currently have?

 

[Outsider]

1970's tech (I had new on the shelf, so I used it), makes good power, but perhaps too much duration for the street, low vacuum at idle, so kind of hard to tune for the street. Newer designed cams seem to make as much power, but are more "friendly".

 

[451Mopar]

Same type question cam up awhile back. The KB pistons with the small dome seemed to calculate out around 10:1 when using a 0.040" head gasket.

 

[Outsider]

Ya, that's why I used the KB flat tops with valve reliefs, they are available with or without domes in some eng apps.

 

[rumblefish360]

Jim (IQ52) can do an ace job in a recommendation here. Seeing how he has more experience in BBM builds, record holding seasons, engine masters entries and understanding of this engine series than 99% of this entire board, I’d run with him any day.

Go to the machine shop and let them offer some advice. A reputable shop will know what works with what. You know what cam and heads you want to use, I'm sure they can make recommendations.

 

[66Satellite47]

I'm sure the cam will work fine with whatever CR you come up with. 10.0 to 1 is hard on the current fuel, especially with iron heads. But the 906 heads at 10.0 will live a long time if you use some additive or mix with race gas or aviation fuel. As IQ said the 906 heads need to be machined to match the cam & valve springs. All things like piston to valve need to be measured not *** UMED.

 

[rumblefish360]

I haven’t a problem with a 10-1 iron headed engine.
The cam I was using was a Purple 292/.508 248*@050.

 

[F4R/T]

No problems with 10.5 here, cams make a huge difference... cylinder pressures are affected.