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383 build #2591894
12/14/18 03:48 PM
12/14/18 03:48 PM
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J Brough Offline OP
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Building a 383 for my challenger. I'm looking for a strong running street/strip engine that will run on 93 octane pump gas. It is bored .030 and will use stock rods and crank. It is going to use 906 heads that have been measured at 92cc. I'm considering custom pistons with a taller CH so that I can push the top of the piston into the open chamber to get .040" quench. The piston would be about .079 out of the hole. With this type of setup I calculate 10.5 CR using a flat top piston without valve reliefs. If I add in 5cc or so for reliefs I'll be in the 10.0 CR range. I've searched a lot within the forum and online for 383 builds using stock open chamber heads, but have not found any builds that took this approach to getting compression out of an essentially stock 383. Anyone have any experience to share on this approach?

Thanks,

John

Re: 383 build [Re: J Brough] #2591899
12/14/18 03:53 PM
12/14/18 03:53 PM
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New York
polyspheric Offline
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Don't bother to read this.


Boffin Emeritus
Re: 383 build [Re: polyspheric] #2591912
12/14/18 04:15 PM
12/14/18 04:15 PM
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Mi,U.S.A.
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mike s Offline
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Blueprint spec for deck is +.022. Blueprint spec for cyl hd cc is 79.5. That should be at least 10.25-1.Much easier to do.


Leave the gun.......take the Cannoli's....Mike
Re: 383 build [Re: J Brough] #2591924
12/14/18 04:46 PM
12/14/18 04:46 PM
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Prospect, PA
BSB67 Offline
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Because it's a lot of work to salvage using 906 heads. It is probably a lot easier now that Diamond is making a std stroke 383 piston. Guess you could spec a 2.00 or 2.01 CD.

Going with a zero deck position and different head would probably be my first choice.

Re: 383 build [Re: J Brough] #2591948
12/14/18 05:31 PM
12/14/18 05:31 PM
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Georgia and Washington
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JMCarter Offline
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By the time you order custom pistons, balance, recondition rods, etc. you could get a stroker kit and have a really strong pump gas motor...just saying.

Re: 383 build [Re: J Brough] #2592006
12/14/18 07:40 PM
12/14/18 07:40 PM
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lewtot184 Offline
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a 2315 piston and 440 source head are the easiest way to do this. custom pistons/pins with a quench dome may be $1000. I know arias has made this type of piston for 440's so they should know what to do. considering the cost of head refurbishing and new custom pistons i think the 2315 pistons and source heads are an easier alternative and might be cheaper; plus this has a good quench distance. if I was building a 383 this is the combo i'd look at first.

Last edited by lewtot184; 12/14/18 09:31 PM.
Re: 383 build [Re: lewtot184] #2592040
12/14/18 08:34 PM
12/14/18 08:34 PM
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Between a rock & a hard place
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cudadoug Offline
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Between a rock & a hard place
You want a REALLY strong street/strip 383? Do this:

383.JPG
Re: 383 build [Re: J Brough] #2592059
12/14/18 08:59 PM
12/14/18 08:59 PM
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Kirkland, Washington
Pacnorthcuda Offline
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You might get compression with dome Pistons and 906 heads, but it's gonna take an act of God and big bucks to get quench.

Re: 383 build [Re: J Brough] #2592090
12/14/18 10:28 PM
12/14/18 10:28 PM
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madscientist Offline
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Measure the quench pads first. I've measured literally hundreds of them on both big and small blocks and unless someone has jacked them up with a grinder or decked the heads crooked the pads will be fairly close. Like within .020 at the most.

Clean them up and mill the heads flat. As long as you are within .020 on all 8 you are good to go.

Then just deck the block and stick the piston out of the deck. You don't need a custom piston to do that. I'm running my junk at .048 out right now. The heads I used were all within .010 so I cleaned them up, milled the heads to the chamber size I wanted and stuck the piston out of the bore to get the CR I wanted. It's not a sin or a crime to stick the piston out of the deck. Also, I've tried quench from .035 to .060 and even .090 and I couldn't get any quench distance to be more sensitive or less sensitive to detonation.

Obviously, you want the quench closer than farther away, but I've seen junk with a big dome and .100 quench make pretty remarkable power and not have detonation issues.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: 383 build [Re: madscientist] #2592110
12/14/18 11:01 PM
12/14/18 11:01 PM
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Washington
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hemienvy Offline
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If you can go .070-over on your block, I think there are
a couple of standard bore 440 pistons you can use that would
stick out of the deck a bit. Then you need to check P-to-V
clearance for your cam.

Re: 383 build [Re: lewtot184] #2592148
12/15/18 12:45 AM
12/15/18 12:45 AM
Joined: Feb 2005
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Prospect, PA
BSB67 Offline
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Originally Posted By lewtot184
a 2315 piston and 440 source head are the easiest way to do this. custom pistons/pins with a quench dome may be $1000. I know arias has made this type of piston for 440's so they should know what to do. considering the cost of head refurbishing and new custom pistons i think the 2315 pistons and source heads are an easier alternative and might be cheaper; plus this has a good quench distance. if I was building a 383 this is the combo i'd look at first.


I don't think he's saying quench dome. Just running the flat top piston out of the hole. A quench dome on a 383 probably wouldn't have much of a compression ratio.

Re: 383 build [Re: BSB67] #2592237
12/15/18 10:37 AM
12/15/18 10:37 AM
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lewtot184 Offline
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Originally Posted By BSB67
Originally Posted By lewtot184
a 2315 piston and 440 source head are the easiest way to do this. custom pistons/pins with a quench dome may be $1000. I know arias has made this type of piston for 440's so they should know what to do. considering the cost of head refurbishing and new custom pistons i think the 2315 pistons and source heads are an easier alternative and might be cheaper; plus this has a good quench distance. if I was building a 383 this is the combo i'd look at first.


I don't think he's saying quench dome. Just running the flat top piston out of the hole. A quench dome on a 383 probably wouldn't have much of a compression ratio.
I understood that, which I wouldn't do, just wanted to offer a simpler solution from past experience. if a custom quench dome piston was ordered then you can make it whatever you want. I think just using a quench head makes things easier. KB400 pistons are an option for higher compression and can still achieve a reasonable quench distance with an alum quench head. several ways to skin the cat. I did a 383 with 2315 piston and '906 heads a couple summers ago. I was surprised at how well it worked no quench and pump gas. I think the real fly in the ointment could be piston to valve clearance. everybody has to have a big hydraulic cam anymore; turd in the punch bowl.

Re: 383 build [Re: J Brough] #2592238
12/15/18 10:47 AM
12/15/18 10:47 AM
Joined: Sep 2006
Posts: 55
Md.
J
J Brough Offline OP
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Md.
Thanks for the responses. I did consider a stroker kit and certainly that is a very proven combo. However, decided to try to see how good I could make a stock 383 with iron open chamber heads perform. I have milled the head flat and measured all the quench pads. The shallowest area is .080 and the deepest is 0.100. So I'm within the .020 suggested. My deck height will be 9.262. When disassembled the deck height measured 9.965 on one side and 9.974 on the other. Decided to take a .003 cleanup cut on the short side and bring the long side down to match. The tallest CH piston I've found is a flattop 0 cc SpeedPro at 1.920. Using that number in the math says the piston will be .004 out of the hole. With a .039 gasket and a 92cc chamber, the CR calculates to 8.8. I'd have to take an additional .035 cut on the deck to get CR into the 9.5 range. That seemed like a lot and would also require milling the intake surfaces of the heads a good bit. A piston with a 1.995CH calculates to 10.5:1CR on a 0 cc flattop. Adding some probably necessary valve reliefs would drop that down to something that should be a bit more realistic for pump gas. The prices I'm getting for a flattop piston with a custom CH are not cheap, but not unreasonable. Again, thanks for sharing your thoughts and experience.

Re: 383 build [Re: J Brough] #2592246
12/15/18 11:10 AM
12/15/18 11:10 AM
Joined: Feb 2005
Posts: 4,309
Prospect, PA
BSB67 Offline
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Originally Posted By J Brough
Thanks for the responses. I did consider a stroker kit and certainly that is a very proven combo. However, decided to try to see how good I could make a stock 383 with iron open chamber heads perform. I have milled the head flat and measured all the quench pads. The shallowest area is .080 and the deepest is 0.100. So I'm within the .020 suggested. My deck height will be 9.262. When disassembled the deck height measured 9.965 on one side and 9.974 on the other. Decided to take a .003 cleanup cut on the short side and bring the long side down to match. The tallest CH piston I've found is a flattop 0 cc SpeedPro at 1.920. Using that number in the math says the piston will be .004 out of the hole. With a .039 gasket and a 92cc chamber, the CR calculates to 8.8. I'd have to take an additional .035 cut on the deck to get CR into the 9.5 range. That seemed like a lot and would also require milling the intake surfaces of the heads a good bit. A piston with a 1.995CH calculates to 10.5:1CR on a 0 cc flattop. Adding some probably necessary valve reliefs would drop that down to something that should be a bit more realistic for pump gas. The prices I'm getting for a flattop piston with a custom CH are not cheap, but not unreasonable. Again, thanks for sharing your thoughts and experience.


Did you get a price from Diamond. They will put wrist pin where ever you want for a small up charge. Their catalog piston has the pin at 1.916. But it already has valve notches. It comes with a modern size ring pack, and is lighter. Will still be more than the 2315 pistons for sure.

If you go the route of making the piston proud, check for cylinder head sticking into open bore above the deck for piston interference.

Re: 383 build [Re: lewtot184] #2592247
12/15/18 11:24 AM
12/15/18 11:24 AM
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Prospect, PA
BSB67 Offline
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Originally Posted By lewtot184
Originally Posted By BSB67
Originally Posted By lewtot184
a 2315 piston and 440 source head are the easiest way to do this. custom pistons/pins with a quench dome may be $1000. I know arias has made this type of piston for 440's so they should know what to do. considering the cost of head refurbishing and new custom pistons i think the 2315 pistons and source heads are an easier alternative and might be cheaper; plus this has a good quench distance. if I was building a 383 this is the combo i'd look at first.


I don't think he's saying quench dome. Just running the flat top piston out of the hole. A quench dome on a 383 probably wouldn't have much of a compression ratio.
I understood that, which I wouldn't do, just wanted to offer a simpler solution from past experience. if a custom quench dome piston was ordered then you can make it whatever you want. I think just using a quench head makes things easier. KB400 pistons are an option for higher compression and can still achieve a reasonable quench distance with an alum quench head. several ways to skin the cat. I did a 383 with 2315 piston and '906 heads a couple summers ago. I was surprised at how well it worked no quench and pump gas. I think the real fly in the ointment could be piston to valve clearance. everybody has to have a big hydraulic cam anymore; turd in the punch bowl.


It just doesn't make sense to me Lew for a 383. Us the KB400 and its a 8.8:1. Why bother? When you do the math to get a quench dome for 906 head with some valve notches, it starts to look a lot like a flat top piston

If you use aftermarket heads, again with a flat top with 0.040 quench 75 cc chamber 3cc valve pocket you get 10:1 CR.


Re: 383 build [Re: J Brough] #2592253
12/15/18 11:46 AM
12/15/18 11:46 AM
Joined: Aug 2003
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KOS Offline
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Originally Posted By J Brough
Thanks for the responses. I did consider a stroker kit and certainly that is a very proven combo. However, decided to try to see how good I could make a stock 383 with iron open chamber heads perform. I have milled the head flat and measured all the quench pads. The shallowest area is .080 and the deepest is 0.100. So I'm within the .020 suggested. My deck height will be 9.262. When disassembled the deck height measured 9.965 on one side and 9.974 on the other. Decided to take a .003 cleanup cut on the short side and bring the long side down to match. The tallest CH piston I've found is a flattop 0 cc SpeedPro at 1.920. Using that number in the math says the piston will be .004 out of the hole. With a .039 gasket and a 92cc chamber, the CR calculates to 8.8. I'd have to take an additional .035 cut on the deck to get CR into the 9.5 range. That seemed like a lot and would also require milling the intake surfaces of the heads a good bit. A piston with a 1.995CH calculates to 10.5:1CR on a 0 cc flattop. Adding some probably necessary valve reliefs would drop that down to something that should be a bit more realistic for pump gas. The prices I'm getting for a flattop piston with a custom CH are not cheap, but not unreasonable. Again,

thanks for sharing your thoughts and experience.


use a steel shim head gasket with that combo and you could skip the head milling and have your desired compression......I have a set of 2315pistons cheap if your interested PM me.

Re: 383 build [Re: BSB67] #2592259
12/15/18 12:03 PM
12/15/18 12:03 PM
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Balt. Md
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383man Offline
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Originally Posted By BSB67
Originally Posted By lewtot184
Originally Posted By BSB67
[quote=lewtot184]a 2315 piston and 440 source head are the easiest way to do this. custom pistons/pins with a quench dome may be $1000. I know arias has made this type of piston for 440's so they should know what to do. considering the cost of head refurbishing and new custom pistons i think the 2315 pistons and source heads are an easier alternative and might be cheaper; plus this has a good quench distance. if I was building a 383 this is the combo i'd look at first.


I don't think he's saying quench dome. Just running the flat top piston out of the hole. A quench dome on a 383 probably wouldn't have much of a compression ratio.
I understood that, which I wouldn't do, just wanted to offer a simpler solution from past experience. if a custom quench dome piston was ordered then you can make it whatever you want. I think just using a quench head makes things easier. KB400 pistons are an option for higher compression and can still achieve a reasonable quench distance with an alum quench head. several ways to skin the cat. I did a 383 with 2315 piston and '906 heads a couple summers ago. I was surprised at how well it worked no quench and pump gas. I think the real fly in the ointment could be piston to valve clearance. everybody has to have a big hydraulic cam anymore; turd in the punch bowl.


It just doesn't make sense to me Lew for a 383. Us the KB400 and its a 8.8:1. Why bother? When you do the math to get a quench dome for 906 head with some valve notches, it starts to look a lot like a flat top piston

(If you use aftermarket heads, again with a flat top with 0.040 quench 75 cc chamber 3cc valve pocket you get 10:1 CR.)



That's what I would shoot for what BSB67 said. Do the math and build a flattop piston quench eng if you can make it work with a closed chamber aluminum head. You may spend a bit more but it will be worth it.


That said some years back I built a mild 383 using stock pistons and bore. I honed the cylinders and then knurled the piston and file fit them since the eng had many miles on it and was still stock bore. Then I used 452 heads that I milled to get a true 9.5 comp and I bowl blended them. I used the old MP .484 cam on a 104 centerline and the RPM intake with a 750 DP. In a Dart street car weighing just over 3600 lbs with me in it the car ran as good as 12.31 @ 110 with 3.91 gears on McCreary G/60-15 tires. And it had no ping on 92 pump with 37 total timing. Ron

Re: 383 build [Re: BSB67] #2592305
12/15/18 01:41 PM
12/15/18 01:41 PM
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lewtot184 Offline
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Originally Posted By BSB67
Originally Posted By lewtot184
Originally Posted By BSB67
Originally Posted By lewtot184
a 2315 piston and 440 source head are the easiest way to do this. custom pistons/pins with a quench dome may be $1000. I know arias has made this type of piston for 440's so they should know what to do. considering the cost of head refurbishing and new custom pistons i think the 2315 pistons and source heads are an easier alternative and might be cheaper; plus this has a good quench distance. if I was building a 383 this is the combo i'd look at first.


I don't think he's saying quench dome. Just running the flat top piston out of the hole. A quench dome on a 383 probably wouldn't have much of a compression ratio.
I understood that, which I wouldn't do, just wanted to offer a simpler solution from past experience. if a custom quench dome piston was ordered then you can make it whatever you want. I think just using a quench head makes things easier. KB400 pistons are an option for higher compression and can still achieve a reasonable quench distance with an alum quench head. several ways to skin the cat. I did a 383 with 2315 piston and '906 heads a couple summers ago. I was surprised at how well it worked no quench and pump gas. I think the real fly in the ointment could be piston to valve clearance. everybody has to have a big hydraulic cam anymore; turd in the punch bowl.


It just doesn't make sense to me Lew for a 383. Us the KB400 and its a 8.8:1. Why bother? When you do the math to get a quench dome for 906 head with some valve notches, it starts to look a lot like a flat top piston

If you use aftermarket heads, again with a flat top with 0.040 quench 75 cc chamber 3cc valve pocket you get 10:1 CR.

I did suggest the the aftermarket head and flat top. the 2315 piston is close to zero deck with a clean-up cut. the OP can put the chambers were ever he wants. the kb400 with the closed chambers can up the compression more. the 383 I built with 2315's had a little over 9:1 with .020" off the heads, no deck clean-up (these heads were what I ran on the R/T so I know what they are).

Re: 383 build [Re: J Brough] #2592306
12/15/18 01:42 PM
12/15/18 01:42 PM
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lewtot184 Offline
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I just offered a simple combo. don't like it-don't do it.

Re: 383 build [Re: J Brough] #2592520
12/15/18 08:59 PM
12/15/18 08:59 PM
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So. Burlington, Vt.
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383 with open chamber heads?

Those things won’t make any power like that smoke


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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