Fastest burning combustion chamber

[Gunner1]

My plan is to build my 440 as a nice street motor. No strokers,. 440 source lightweight 3.75 steel crank longer H beam rods and flat top pistons. I’m interested in CNC ported 440 sized ports. This is my first Chrysler big block. What I’m concerned about is flame speed. The chevys I built had a max bore of 4.155 with high swirl chambers. The 4.350 bore is new for me. 3.75 stroke long rod higher tic dwell time with a tight .035 piston to head I’m hoping will let me run high 10 to 1 to a low 11 to 1 on 91 pump. 3400 pound car 3000 stall 355 or 391 gears. RPM air gap and a 750 dp holley. So who has the best fast burn chamber.

 

[68Dart470]

I think you’re crazy not to take advantage of 50+ absolutely free cubic inches especially with a heavy car.

 

[Dan64]

I would look at Trick Flow 240's for standard port size but I gotta ask Why no strokers?. You could build it bigger but more mild and have gobs of torque. I would shoot more for 10 to 1 compression for 91 pump gas.

 

[slepr1]

I'm not a fan of spending large money on building better old school heads. I spent that money when aluminum heads were still crazy expensive. Couple years ago I built my 440 with Edelbrock aluminum heads much cheaper. I run 10.7 cr now on premium gas with no issues and very happy with them.

 

[gkent]

.035 quench is a tad too tight. Another .010 would make it ideal.

 

[Lefty71]

If you run high 10's with that combo, i'll be damn surprised..... just sayin. I'd like to hear more about the magic stick your gonna use in there. Thx, Lefty71

 

[Gunner1]

Most of my experience is SBC 400's. I like a quick revving motor with a light rotating mass. A 4.15 stroke has a taller outer circle of mass. I would ideally like to build a street based 440 Circle track claimer motor so to speak. Light bobweight then turn the counterweights down un a lathe for a small hole balance. Besides i'll never hook up 275 street tires.

 

[Gunner1]

If you run high 10's with that combo, i'll be damn surprised..... just sayin. I'd like to hear more about the magic stick your gonna use in there. Thx, Lefty71

LOL Oh no. High10 to 1 compression 440 source sells at lightweight steel crank in different strokes.

 

[Lefty71]

Most of my experience is SBC 400's. I like a quick revving motor with a light rotating mass.

Mopars are heavy, and heavy duty, plain and simple. You can see it in the bearing journal sizes..... that's why we can cut things down to Chevy sizes in our Frankenmotor Strokers. Here's a cheapie project you may be interested in, but I personally have never tried (cuz the EZ stroker is too tempting and is a proven winner).. I would love to do a 400BBM with the stock 383/400 stroke crank, a relatively wild cam and Maxie sized heads in a combo similar to yours. Many will say "cant get an intake" but as long as hood clearance doesnt bother you, Indy will have what you need.

 

[Lefty71]

LOL Oh no. High10 to 1 compression 440 source sells at lightweight steel crank in different strokes.

My bad (duh)!!
So, you need to run some calculations to learn where the dynamic compression lies.... any clue what the desired cam will be?? I don't think flame speeds gonna be any kind of problem for you.

 

[Gunner1]

Those 400 builds do look so tempting. Piston dwell with such a short stroke and long rod can cause intake valve shrouding as the intake valve chases the piston down the bore. I dont know what intake lobe you would need to use but I'll bet that would be a screamer. But I have no shop or garage anymore. And at 74 this is my when I die bury it with me project. I may race it or not. I doubt I'll cage it. Mostly a burger night car.

 

[Gunner1]

My bad (duh)!!
So, you need to run some calculations to learn where the dynamic compression lies.... any clue what the desired cam will be?? I don't think flame speeds gonna be any kind of problem for you.

I'm thinking something in the 250/260@50 on a 106 LS installed at 102 to 100 ICL solid flat tappet with EDM pinhole lifters. Lift dependent on flow numbers.

 

[Cranky]

I'm thinking something in the 250/260@50 on a 106 LS installed at 102 to 100 ICL solid flat tappet with EDM pinhole lifters. Lift dependent on flow numbers.

The larger bore of the 400 block helps to unshroud the valves a bit and the shorter stroke imo, helps with making quicker rpm. Imo, 3400 isn't all that heavy but 2900 is much better! And yes, the right cam with the higher static CR can help as they bleed off cylinder pressure at the lower rpm ranges and once the engine is spooling up, it doesn't have enough time to ping.....so long as everything is right. Too much timing, CR too high, cam isn't quite right, too lean....and a few other things can mean the destruction of a high static CR engine. And don't worry too much about having .035 piston to head clearance. I've seen them tighter than that before with steel rods. Most consider .040 as safe and .005 less isn't going to make or break the bank unless you're running aluminum rods and then you better be .040+ and .050 is considered safe.

 

[Gunner1]

Something like this but with a tighter lobe seperation, https://www.lunatipower.com/voodoo-solid-flat-tappet-cam-chrysler-361-440-280-288.html
Tightest i've run is 28. LOL you could read the piston stamp info on the heads quench pad when we pulled it down.

 

[Cranky]

Something like this but with a tighter lobe seperation, https://www.lunatipower.com/voodoo-solid-flat-tappet-cam-chrysler-361-440-280-288.html
Tightest i've run is 28. LOL you could read the piston stamp info on the heads quench pad when we pulled it down.

I've seen that more than a time or two and especially with the dirt guys! The closest I've done was .019 (by mistake) but it did it until the owner of the car hit it with a 150 shot.....then it blew out a cylinder but it ran a 10.0 off the trailer and did it for 2 more passes before the stooopid gas lol

 

[Curiousyellow71]

Not sure you wouldn't go w more stroke in a 440? We usually consider quench .035 the minimum. But I really don't think there is anything to be gained with it that tight on the street.
From what was described building the 400 b stroker is usually quicker revving then a 440 rb with its lighter rotating assembly. Run b counterbalances, bbc 2.2 journals and .990 pins and a 452-512 b stroker will rev like your wanting. Keep in perspective that a 400 b has a taller deck then a 454 chevy.
I think you combustion chamber efficiency is going to be nearly identical between the edelbrocks, trick flows and stealths. But port flow is going to vary wildly and the bigger cnc heads are not going to stand out unless you use a much bigger cam, at least not for the $ spent.
I think the original koffel b-1 heads were more efficient then most the newer heads but were not a direct replacement head like the trick flow or edelbrocks....b1 (original) heads took special pistons, headers and intake. Perhaps the small combustion chamber likely had a quicker burn.. they were only 64cc. The b-1 that was in our cuda was 782hp at 7600 rpm. It was a 452(400 w 440 crank) with 6.86" aluminum rods and 1.23 ch pistons and very, very expensive. I think it would've been difficult to make a engine of that size to rev any quicker.

 

[Gunner1]

The main reason for the tight quench band is chamber turbulence when running pump on the street. It has let me run more compression “static” with a tighter LS cam which blows down the below 3k “dynamic” pressure. Like someone here mentioned over 3k rpm there is not so much time for ping to form. With a reverse dome or flat top when the piston come rushing up to TDC it squishes everything into the chamber and mixes the fuel mixture more evenly. Also the reason for the 440 is I have one and I have no place to build something and save parts. My buddy says we can do the motor at his place but he’s got no room for storage. We’re building a 327 mouse there now. Oh yeah. Fixed income disabled old dude. Expensive is a girl friend I can’t afford anymore. She’s sure pretty to admire though. The more I reread your post the better a 451/512 looks. Buy my parts then sell the 440 when it’s installed.

 

[Budnicks]

a closed chamber head in 84 or 75cc would do it well
flat tops with a 'near zero' deck height with proper valve reliefes
use a 0.039" compressed gasket if 'you think'
you need the 0.040" of quench
you also can unshroud the intake valves in the cylinder edges too
with a small peanut grinder, on the area where the intake is near the edges
use the head gasket as a template
seems with a 4.35" bore it shouldn't be any issues,
I've still done it on a few engines

Ported Eddys or AFR (near double price) would do it,
need something
in the 320-330cfm int. @ 0.600"+ gross valve lift range
the angle plug & combustion chamber shapes are really good aids
need 700hp

so would several on the INDY's offerings
at a higher price thou

stock stroke street(able) 440 444-447cid engine
"on 91 oct. pump gas"
running a 3500# car in the 10's is an accomplishment

it's not impossible

the car getting up on the tire & moving out quickly
is 1/2 of it

 

[SlinktRR]

I'm with you gunner. After having a big stroker motor I kind of miss the RPM of a light rotating assembly. Let us know what cam you end up using on this!

 

[Gunner1]

a closed chamber head in 84 or 75cc would do it well

Ported Eddys or AFR (near double price) would do it,
need something
in the 320-330cfm int. @ 0.600 gross valve lift range
the angle plug & combustion chamber shapes are really good aids
700hp

so would several on the INDY's offerings
at a higher price thou

stock stroke street(able) 440 444-447cid engine
"on 91 oct. pump gas"
running a 3500# car in the 10's is an accomplishment

it's not impossible

the car getting up on the tire & moving out quickly
is 1/2 of it

Caltracs showed up today. I bought std splits for now. I’ll buy the rest later. I’d be happy if this car is as fast as my SRT8 300C was. It’s not gonna be a drag car just a poser. I just want it to sound like it’s one.