383 build?

[Gary Stavely]

I'm with Don, but it's up to you. Many aluminum intakes offer surprising increases in horsepower and they don't "look" aluminum once painted.

I understand but the intake I have is a great intake and better than that it is paid for lol. I am putting a lot of money into the total restoration of the car as it is and thats something I can always add in the future.

 

[monaco66coupe]

Well since 906 heads come in around 88-90cc And KB's advertised numbers are "Optimistic" 906 heads & 10-1 with the KB-162 isn't gonna happen....

I have a second set of forged pistons that the machinist says is rated at 11.0:1 @88cc
13.0:1 at 78CC
is it better to use the above and thicker gaskets to get the cc up, in order to lower the compression a bit?

 

[monaco66coupe]

I also have a set of rebuilt 915 large valve heads, would that Improve the number of the 162? The specs say 78.5 cc on that head.
Hopefully this isn't hijacking the thread, I hope the OP could use the same advice.

 

[Gary Stavely]

I also have a set of rebuilt 915 large valve heads, would that Improve the number of the 162? The specs say 78.5 cc on that head.
Hopefully this isn't hijacking the thread, I hope the OP could use the same advice.

No worries I thought of those pistons but personally I would like to use the 2315's

 

[1 Wild R/T]

I also have a set of rebuilt 915 large valve heads, would that Improve the number of the 162? The specs say 78.5 cc on that head.
Hopefully this isn't hijacking the thread, I hope the OP could use the same advice.

that 78.5 is the NHRA blueprint spec... In reality they typically come in around 81-82 cc..

Using numbers from my short block build & 81CC for the heads plus .021 for a steel shim gasket the Diamond Piston calculator puts the C/R at exactly 9-1

 

[monaco66coupe]

that 78.5 is the NHRA blueprint spec... In reality they typically come in around 81-82 cc..

Using numbers from my short block build & 81CC for the heads plus .021 for a steel shim gasket the Diamond Piston calculator puts the C/R at exactly 9-1

so, the KB400 be a better choice for getting closer to the original 383 magnum? I have not yet assembled it. I wish I knew the number of the other set i have, to look it up. would 11.0:1 at 88cc seem a bit radical? they came with the engine, but the machinist is concerned about fuel problems.
thanks for your help in advance!

 

[1 Wild R/T]

KB400 is a domed piston, use the 906 head, steel shim gasket & you get roughly 9.2 if the head measures 88cc & 9.0 if it measures 92cc

If the pistons you have are the old TRW 2293's (shown below) you might be able to mill away part of the dome... Need to do some measuring first but I've heard it can be done.....

 

[monaco66coupe]

KB400 is a domed piston, use the 906 head, steel shim gasket & you get roughly 9.2 if the head measures 88cc & 9.0 if it measures 92cc

If the pistons you have are the old TRW 2293's (shown below) you might be able to mill away part of the dome... Need to do some measuring first but I've heard it can be done.....

View attachment 1098547

thank you for going to so much trouble. I sure wish I had the original piston performance type specs. but these days that isn't happening apparently. I am hoping to get as close as possible to the original, as it is going in my 69 Cuda 383 four speed car, Bone stock original. So, The piston set I have is domed, and seemed pretty radical to me. I will get a picture of it and the number on it and post again. Thanks!

 

[AustinGriggs]

I have 2315 pistons in my zero decked 383 w/915s, i also run a cam bigger than .500 with no reliefs. It's .534 on the exhaust which is the closest one to interferance (and its not even that close) using a 1.74 valve. Cam is 274 int./282 exh. I shift it at 6000 and it gets street used all the time. I kept to 2.08 on the intake just because i didnt thing a 383 needed all that. Car put down 338hp to the tire and ran 7.98 in the 1/8 with 3.55 gears.

 

[Gary Stavely]

I have 2315 pistons in my zero decked 383 w/915s, i also run a cam bigger than .500 with no reliefs. It's .534 on the exhaust which is the closest one to interferance (and its not even that close) using a 1.74 valve. Cam is 274 int./282 exh. I shift it at 6000 and it gets street used all the time. I kept to 2.08 on the intake just because i didnt thing a 383 needed all that. Car put down 338hp to the tire and ran 7.98 in the 1/8 with 3.55 gears.

Awesome thx!

 

[1 Wild R/T]

I have 2315 pistons in my zero decked 383 w/915s, i also run a cam bigger than .500 with no reliefs. It's .534 on the exhaust which is the closest one to interferance (and its not even that close) using a 1.74 valve. Cam is 274 int./282 exh. I shift it at 6000 and it gets street used all the time. I kept to 2.08 on the intake just because i didnt thing a 383 needed all that. Car put down 338hp to the tire and ran 7.98 in the 1/8 with 3.55 gears.

What constitutes "Not even that close"? Have you actually measured it? What head gasket are you running? Don't get me wrong, I'm glad it's working for you & I'd like to know more... What cam? How much overlap? Zero decked means .012 closer than blueprint spec...

 

[AustinGriggs]

What constitutes "Not even that close"? Have you actually measured it? What head gasket are you running? Don't get me wrong, I'm glad it's working for you & I'd like to know more... What cam? How much overlap? Zero decked means .012 closer than blueprint spec...

I had the block decked .020 which actually brought me to .002/.003 out of the hole. Head gaskets are just standard .039 Felpros. The cam is the Hyd roller below, I use solid roller lifters and Harland sharp rockers with lash around .005 cold. I do not have the measurements you are asking for as this cam change was done on a running motor without pulling the heads, I do however have a video from the borescope somewhere, I’ve shared it on here before. Cam is installed “strait up”. It’s the cams with lots of duration and a late exhaust valve closure that will cause the first interference problem, piston don’t care how far the valve opens so long as it gets out of the way before the piston gets there.

 

[BSB67]

I had the block decked .020 which actually brought me to .002/.003 out of the hole. Head gaskets are just standard .039 Felpros. The cam is the Hyd roller below, I use solid roller lifters and Harland sharp rockers with lash around .005 cold. I do not have the measurements you are asking for as this cam change was done on a running motor without pulling the heads, I do however have a video from the borescope somewhere, I’ve shared it on here before. Cam is installed “strait up”. It’s the cams with lots of duration and a late exhaust valve closure that will cause the first interference problem, piston don’t care how far the valve opens so long as it gets out of the way before the piston gets there.

I really like the choices you've made.

A few questions:
1) What is the cranking cylinder pressure?
2) Have you checked the lash hot? What is it?
3) Does it clack like a solid or is it quieter?
3) You installed it at 110° ICL correct?

I'm surprised it does not like more rpm.

The hydraulic roller will be slower off the seat than a similar seat timing fast rate hydraulic FT. This will free up a little P-V clearance.

 

[SlinktRR]

Get custom dished pistons with pads for quench to work with the 78cc chambers for 9.5-10:1 compression. If you want stock look, get the mopar performance m1 dual plane. It's basically the stock iron intake in aluminum. Paint it and it will look like a stocker. Your back will thank you.

 

[Gary Stavely]

Get custom dished pistons with pads for quench to work with the 78cc chambers for 9.5-10:1 compression. If you want stock look, get the mopar performance m1 dual plane. It's basically the stock iron intake in aluminum. Paint it and it will look like a stocker. Your back will thank you.

I like the intake I have the casting numbers are #2806301, I believe it is one of the better stock intakes and its been hot tanked and is really for paint. Where would I find custom dished pistons? They sound expensive lol! I really don't understand what is wrong with the TRW speed pro 2315? Gonna have to CC my heads but why would they advertise them as compatible with the 78cc chambers? Seems like they are working for Austin, I will talk to the machine shop in the next couple days but I am really hopeful the speed pros will work...

 

[AustinGriggs]

The 2315s have taken me from Alabama to: Washington DC, Dallas, Kansas, Virgina Beach, Philadelphia, Myrtle Beach and everywhere inbetween. Ive ran them hard, overheated, out of fuel, previously before the 915s with garbage valve seals/guides on the OG 440source heads and even had a dead cylinder that hydrolocked and bend the rod... which I reused the piston and had a new rod balanced and put back on it. My block is decked with the pistons coming just out of the hole and I have a way more argressive cam than you are planning for and a 1.74 valve (which i would recommend moving too) I'd also run a .020 gasket in your application to take advantage of the quench.
That being said, measure your stuff... and don't trust me. But, there is no reason to not run the 2315s in my opinion and experience.

I really like the choices you've made.

A few questions:
1) What is the cranking cylinder pressure?
2) Have you checked the lash hot? What is it?
3) Does it clack like a solid or is it quieter?
3) You installed it at 110° ICL correct?

I'm surprised it does not like more rpm.

The hydraulic roller will be slower off the seat than a similar seat timing fast rate hydraulic FT. This will free up a little P-V clearance.

1) IDK, but Ill check that before too long.
2) No, but again Ill check.
3) They make noise yes, but it's much better than most solids that ive been around.
4) No, this is 106 installed with a lobe sep of 110

It does like more RPM, but it made peak power on the dyno @5800 so i shift it at 6k

 

[BSB67]

.........Where would I find custom dished pistons? They sound expensive lol! I really don't understand what is wrong with the TRW speed pro 2315? Gonna have to CC my heads but why would they advertise them as compatible with the 78cc chambers? Seems like they are working for Austin,.......

Exactly. 383-915's-2315's, A match made in heaven for what you are doing. Compression in the 9's and quench. No need to make it complicated. Keep an eye on the combustion chamber size and land on a compression ratio and cylinder pressure that works with your local gas and elevation.

People don't go to the track much anymore, so they might not appreciate how well Austin's car runs. A 383 street car that runs mid 12's at 110 mph that will kick the butts of 90% of the street 440 guys running around.

 

[BSB67]

The 2315s have taken me from Alabama to: Washington DC, Dallas, Kansas, Virgina Beach, Philadelphia, Myrtle Beach and everywhere inbetween. Ive ran them hard, overheated, out of fuel, previously before the 915s with garbage valve seals/guides on the OG 440source heads and even had a dead cylinder that hydrolocked and bend the rod... which I reused the piston and had a new rod balanced and put back on it. My block is decked with the pistons coming just out of the hole and I have a way more argressive cam than you are planning for and a 1.74 valve (which i would recommend moving too) I'd also run a .020 gasket in your application to take advantage of the quench.
That being said, measure your stuff... and don't trust me. But, there is no reason to not run the 2315s in my opinion and experience.



1) IDK, but Ill check that before too long.
2) No, but again Ill check.
3) They make noise yes, but it's much better than most solids that ive been around.
4) No, this is 106 installed with a lobe sep of 110

It does like more RPM, but it made peak power on the dyno @5800 so i shift it at 6k

Thanks.
Try a higher shift point and see what happens. Remember, it's the average hp that gives you the et/mph. The hp past peak will still be higher than shift recover rpm hp. Obviously, your converter matters a bunch here.

Be cautious on using the term straight up, as to many of us it is ICL=LSA. You cam is 4° advanced. It just so happens that the manufacturer groung the 4° in for you.

Good to know on the noise, considering most aggressive hydraulic lifter make noise anyways.

 

[dvw]

None of the stock intakes are "great". A good dual plane will look close if painted and offer a fair amount more performance.
Doug

 

[Challenger340]

I am assuming you are saying the 2315 can be a PITA because of clearance issues? My cam is .444 int .466 exhaust , to me these pistons seem like the logical available choice to reach the right compression level.

Speed Pro 2315's with no Valve reliefs can be a PITA if using any Camshaft lifts approaching .500"
because
when meeting or exceeding that .500" Lift there can be Piston to Valve issues and best to check ? mid 400's is not a problem and a drop in and go.