Piston recommendations

[rumblefish360]

Exactly. IIRC, the Comp XE285HL is a [email protected].
Here’s my small block card of the same cam.
(I had Comp narrow the C line to 108)

 

[BSB67]

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?

Although we do not really know what your goal is, I cannot think of a worse combination of parts than a 383 w/ KB pistons w/ 285Hl cam.

 

[Ghostrider 67]

Yes, you will need either 4,6, or 8 of them... I personally recommend 8.

 

[ykf7b0]

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.

I have been running 10.62 to 1 compression for the past 7 years with my street/strip 440 with closed chamber 915 iron heads. I usually get 92 or 93 octane fuel but have been forced to top off with 87 more than once and was fine. Cams with enough overlap will bleed off compression but with a stock profile it would probably be a mistake with lots of pinging. As far as pistons go, I really like Wiseco Pro Tru forged and they have served me well and are strong enough to handle the 175 shot of nitrous that I tap into from time to time. My 440 and a recently built iron head 383 Chevy stroker (10.2 to 1) both were built with Wiseco and never a problem.

 

[rumblefish360]

Why?

Although we do not really know what your goal is, I cannot think of a worse combination of parts than a 383 w/ KB pistons w/ 285Hl cam.

 

[Dimension]

Although we do not really know what your goal is, I cannot think of a worse combination of parts than a 383 w/ KB pistons w/ 285Hl cam.

My goal is basically reproduce what Hot Rod did in bolting on some easy upgrades thus bringing the 383 more to life. What really convinced me that the 383 needed some upgrades was after watching Nick's Garage where he replicated what Hot Rod did. After reviewing the specs of the and the RPM range of the intake and cam I saw that Comp Cam recommended that the motor have 10:1 compression. In Nick's video he stated the compression in his motor was 9 something but seeing what Comp Cam recommended I wanted to see what my options are in possibly getting 10:1 in my motor. From what the initial majority stated in this thread was that 10:1 was not possible. I'm fine with not being able to active 10:1 with my setup which I am fine with.

What pistons would you recommend using in achieving the best possible setup with what I currently have?

 

[66Satellite47]

Dimension, I have always taken the magazine articles with a grain of salt, especially Hot Rod. The best power/torque improvement you can make is to pocket port the 906 heads. As you go bigger with the cam, this is more important. If the BB cam is the same as what Rumblefish posted, that should make good power. I'm not familiar with what pistons are available today for a 383. You could go to a custom piston from Arias, Venolia, Diamond and get whatever CR you want. Using the Mopar porting template kit on the 906 heads will give you great results. Using a really good machine shop does make a ton of difference, especially one that knows Mopars, bowties are not the same.

 

[joe smith]

I have been running 10.62 to 1 compression for the past 7 years with my street/strip 440 with closed chamber 915 iron heads. I usually get 92 or 93 octane fuel but have been forced to top off with 87 more than once and was fine. Cams with enough overlap will bleed off compression but with a stock profile it would probably be a mistake with lots of pinging. As far as pistons go, I really like Wiseco Pro Tru forged and they have served me well and are strong enough to handle the 175 shot of nitrous that I tap into from time to time. My 440 and a recently built iron head 383 Chevy stroker (10.2 to 1) both were built with Wiseco and never a problem.

My stock 67 440 with its 915 heads did pretty well until I installed some " light " springs in the distributor, always an easy way to make your car run better.. It had forged pistons that the machine shop calced out to be around 9.4 to 1 cr....
I had to turn around and go directly back home to reinstall the heaver springs back in the distributor.... It really rattled with the light springs....

 

[BSB67]

What pistons would you recommend using in achieving the best possible setup with what I currently have?

Icon IC687. Cut the block to zero deck . Gasket to your liking. 9.5 to 9.9:1 CR w/ your 906's. With this, you can switch to a aluminum head in the future and achieve a good CR and good quench.

Don't confuse any stock rebuilt head with a good rebuilt factory head. If you are not spending $1,500 on your heads, they are not going to be good, and it will show in the performance.

The Cam you are considering verses what was used in the Hot Rod article are not even in the same realm, if I am looking at the correct article. Plus, the valvetrain/lifter will completely loose control with your cam choice well before that little 383 gets to peak power. Get a small solid lifter cam. If that puts you outside your budget. Stop the project until you can afford the solid cam and associated valvetrain.

my two cents.

 

[Dimension]

Icon IC687. Cut the block to zero deck . Gasket to your liking. 9.5 to 9.9:1 CR w/ your 906's. With this, you can switch to a aluminum head in the future and achieve a good CR and good quench.

Don't confuse any stock rebuilt head with a good rebuilt factory head. If you are not spending $1,500 on your heads, they are not going to be good, and it will show in the performance.

The Cam you are considering verses what was used in the Hot Rod article are not even in the same realm, if I am looking at the correct article. Plus, the valvetrain/lifter will completely loose control with your cam choice well before that little 383 gets to peak power. Get a small solid lifter cam. If that puts you outside your budget. Stop the project until you can afford the solid cam and associated valvetrain.

my two cents.

Thanks for the feedback. The cam should match what was given in Nick's Garage video where he did the exact setup that I am attempting to do on the dyno. After reading the article and watching his video that is when I decided to go the same route. Now, in his video the cam he shows on his sheet does read "Comp CaM CRB XE285HL-10". When I went to Comp's website the only cam that came up when I did a search for XE285HL was this one for a 383 https://www.compcams.com/xtreme-ene...ulic-flat-cam-k-kit-for-chrysler-383-440.html

 

[66Satellite47]

Thanks for the feedback. The cam should match what was given in Nick's Garage video where he did the exact setup that I am attempting to do on the dyno. After reading the article and watching his video that is when I decided to go the same route. Now, in his video the cam he shows on his sheet does read "Comp CaM CRB XE285HL-10". When I went to Comp's website the only cam that came up when I did a search for XE285HL was this one for a 383 https://www.compcams.com/xtreme-ene...ulic-flat-cam-k-kit-for-chrysler-383-440.html

Let us know how it turns out. Cam selection is a tricky thing. Pistons not so much so.

 

[68-500]

With 906 heads i would find a piston with a quench pad. Especially if you want near 10:1 compression ratio. Either that find some 915 heads, 1.920 compression height pistons, and run a .020 steel shim head gasket that should get you near 10:1 and .035-.040 quench. Should run fine in premium gas.

 

[Dimension]

Let us know how it turns out. Cam selection is a tricky thing. Pistons not so much so.

Everything is tricky in my opinion in selecting the correct parts to get everything work together in harmony and to maximize their production. Because of this is the reason why I am here to get ideas and feedback.