383 build?
- Thread starter Gary Stavely
- Start date
Gary Stavely
Well-Known Member
What about a 0.039 Gasket? Or possibly removing that dome? .040 pistons are unavailable right now
AustinGriggs
Well-Known Member
The .039 is what I was referring to as “regular” you could do that sure but that would be a shame. I’d be more inclined to either mill the block some and run the .039s and pick more fitting parts throughout to compliment it.
KB162s are available now on summit for you 4.290 bores, they ‘should’ rest around .024 in the hole and with a .022 gasket you will be in for about 9.4:1 which will work good and there might be a quench effect there at .046ish.
Gary Stavely
Well-Known Member
I kinda want cast or forged pistons, I could look at complimenting with a better intake . Using just the summit calculator I come up with 10.1:1 with a .039 Gasket, if that is the compressed spec. It's the exact same if we mill those domes off and use a .022 Gasket. At this point I am not even sure the Icons are available but if they are hopefully we can make them work. How much would you recommend decking that block if I keep those domes on and run the thinner gasket?
Last edited:
1 Wild R/T
Well-Known Member
Milling domes worked on older pistons because the dome was extra thick... The Icons are a much more modern design & probably can't be milled.....
SlinktRR
Well-Known Member
Yeah I didn't mean just use the shelf icons, the point I was going for is that the D dish pistons can be customized to have any CC dish you need to dial in the CR to match your heads. Mine are custom 10:1, although with the design of the TF heads I could have probably gone 10.5 or 11:1 safely for pump gas. And austin yes I was wrong, stroke does matter wasn't thinking about that properly.
If you ever upgrade your heads on the 383, this thread from FABO may steer you towards trick flow 240s. 600+ bhp on stock stroke 383.
https://www.forabodiesonly.com/mopar/threads/trick-flow-270s-or-240s-on-a-383.430479/
If you ever upgrade your heads on the 383, this thread from FABO may steer you towards trick flow 240s. 600+ bhp on stock stroke 383.
https://www.forabodiesonly.com/mopar/threads/trick-flow-270s-or-240s-on-a-383.430479/
BSB67
Well-Known Member
The 687 is a beautiful and perfect piston, if: 1) you use an aluminum head, or 2) use an open chamber factory cast iron head.
Challenger340
Well-Known Member
So I will assume from that statement that you do NOT want a Hypereutectic Piston ..... correct ?
So NO BB Mopar Torque Plate available ? So you've been advised "NOT to use KB's" ?
For the record.... we've used the KB Pistons dozens of times.... we've NEVER had a problem !
And the only 'problems' we've ever heard of with others ? usually diagnoses right back to some village idge-yot doesn't know what they are doing and using incorrect Fitting or ring end gaps initially because they are too arrogant to READ !
Just say'in....
as long as you have/use a BB Mopar Torque Plate when fitting
and
can READ and apply the correct ring end gap recommendations
You will NEVER have a problem with the KB's.
And a little off topic.....
but whatever you decide.... it may be advisable for you to hurry up and order your parts asap ?
because,
alot of BB Mopar stuff is going "NLA" with NO re-stock dates being forwarded ?
At our shop here we specialize in BB Mopars... that's all we do... and I did NOT take this decision lightly to spend $30K last month stocking up on BB Mopar stuff just to be able to stay open ?
Engine Bearings (various sizes)
Forged Pistons (various sizes)
Camshafts
Lifters
T/Chain & Gearsets
Gaskets
you name it.... LOTS of stuff going NLA and who knows when ? if ever ? they are coming back on these low-numerical 40-50 years out of production engines.
1 Wild R/T
Well-Known Member
Thanks for that info.... Guess I'm buying parts this month instead of next year...
- Local time
- 7:24 AM
- Joined
- Mar 28, 2014
- Messages
- 35,126
- Reaction score
- 57,677
- Location
- South Louisiana
THIS!!
monaco66coupe
Well-Known Member
Thanks!
I can save these new KB 162 pistons for another project. So Using the stock 906 head with the original 383 magnum cam, comp cam 21-21-4, what is the piston I need to get at least close to the original rating?
1 Wild R/T
Well-Known Member
with the Icon IC-687 and a steel shim head gasket using what I consider standard numbers you get 9.24 which is pretty good for an iron headed pump gas engine...
https://www.cnc-motorsports.com/ico...ts-bb-chrysler-383-dome-4-5cc-bore-4-310.html
monaco66coupe
Well-Known Member
thanks for that, I am getting the Idea, I still have the 67 915 heads as well, , would that help the CR?
- Local time
- 7:24 AM
- Joined
- Mar 28, 2014
- Messages
- 35,126
- Reaction score
- 57,677
- Location
- South Louisiana
Just as a quick note, in the GTO, the 421 Tripower when I had it rebuilt from .030 over to .035 when I had a big end rod bearing take a crap, I was reluctant to drop the CR too low, (factory 11½:1) but knowing I was keeping the hand ported iron heads, and that detonation would damage an engine I was rebuilding hopefully for the last time, and my wife didn't even notice the rod knock, so knowing what "pinging" was without a "pinging now" light on the dashboard wasn't likely, I ordered dished forged aluminum Race Tech pistons for it with my builder's blessing. They net around a 10:1 CR, and I don't have any problems with pinging on 92-93 octane premium.
From a number of builds that I've read Jim Laroy do, it seems like CR is not the most important factor in making power, and detonation can tear apart a motor, I believe it's responsible for the damage to that crank end rod bearing (it was cracked in half) and it's better to be safe than sorry.
If you can temper the CR with a head gasket, I'd say build it for 10:1 with a thin metal gasket, and that can be reduced with a thicker gasket.
JMO
Gary Stavely
Well-Known Member
Well after a lot of thought and pondering. Summit had 2 sets of speed pro 2315's coming in one was spoken for but I ended up purchasing the second set. I think they will work the best for all intent and purposes on my build... We will see if they show up but they are scheduled to arrive in Ohio on the 13th of next month. As mentioned earlier these parts are getting harder to find and thats the case with this 67 coronet in general... Hopefully this all works out and lasts me for the rest of my years anyways, who cares after that lol. Thanks for all the help!
Last edited:
Babyblue66
Well-Known Member
I built a 383 with speed pros, 906s with 214 181valves,a little porting, 8.8 Compression. With a stock intake, 750 quick fuel, comp xe268 and headers. 380hp 421tq on the dyno.
Babyblue66
Well-Known Member
So power can be made with a stock Intake and mild compression.
Gary Stavely
Well-Known Member
This is from a old thread but I too feel that stock intake ain't half bad, it is something that can be changed in the future if need be but I would like to try and make it work and I think the edelbrock avs 2 will compliment it. I did pick up a bit more cam though, summit 6401.
https://www.forbbodiesonly.com/mopa...ntake-manifolds-vs-edelbrock-performer.77891/
BSB67
Well-Known Member
That old thread is well done. The only problem is they were testing intake manifolds when the weak link in the motor was elsewhere and not the intake manifold. Likely the cam and carb. That is why the results are essentially identical for all the tests, within expected repeatability considering the variables.
The good news is that if 14.00 @ 100 mph is the level of performance you are looking for, the 301 intake is perfectly fine.
Last edited:
Babyblue66
Well-Known Member
It made the best power and torque with the stock type 1/4 inch thick gasket that is open. Not a 4 hole gasket. 1 inch spacer and 4 hole spacer were down a few hp on this particular engine.
Similar threads
