Everyone else asks, (512 build) why not "ask the forum", lol

[PROSTOCKTOM]

I am not sure what your end goal is, but it sounds like a street car if you're running 3.54 gears in a heavy car.

If all you want is a 6000 RPM engine a 249/255 duration cam is a little large in my opinion for a 3400 pound vehicle.

I have a well built 499" RB in a 63 Plymouth Fury that has a Comp Cams XR274R solid roller 236/ 242@ .050" .564"/ .570"

tt will swing way past 6000 with ease while pulling like a freight train.

Currently it has a well ported Victor intake on top, but I have an Indy MW single plane I plan to switch to this winter.

Each will have there own opinion, but I think your cam choice is way off for the weight of the car and gearing.

Tom

 

[plymouth67]

The 512 in my 71 Challenger is not as built as your wanting to go and I can tell you, it keeps up with Hellcats as is. It has a 251 at .050 Lunati hydraulic roller cam. Mine has about the same compression as your talking about and an Edelbrock RPM intake. It also only has the 440 source stealth heads on it. It dynod at 665 hp and 691 ft/lbs torque. Using the parts your wanting to use (minus the 6 pack set up) you should have no problems tracking down Hellcats.BTW...your car looks sweet!!

 

[mopowers]

The 512 in my 71 Challenger is not as built as your wanting to go and I can tell you, it keeps up with Hellcats as is. It has a 251 at .050 Lunati hydraulic roller cam. Mine has about the same compression as your talking about and an Edelbrock RPM intake. It also only has the 440 source stealth heads on it. It dynod at 665 hp and 691 ft/lbs torque. Using the parts your wanting to use (minus the 6 pack set up) you should have no problems tracking down Hellcats.BTW...your car looks sweet!!View attachment 1716463661

Those are nice numbers. What kind of work was done to the intake and heads? Do you recall what the peak hp and torque rpm was? Also, what carburetor was used for the dyno pulls?

 

[plymouth67]

I'm really not sure what all was done to the heads. The intake has some porting done and the divider milled down about 1/2 ". Peak torque was 4700 rpm and peak horsepower at 5900. Carb is a Holley 850 DP.

 

[rikkitik]

I am not sure what your end goal is, but it sounds like a street car if you're running 3.54 gears in a heavy car.

If all you want is a 6000 RPM engine a 249/255 duration cam is a little large in my opinion for a 3400 pound vehicle.

I have a well built 499" RB in a 63 Plymouth Fury that has a Comp Cams solid roller @ 236/ 242@ .050" and it will swing way past 6000 with ease while pulling like a freight train.

Actually, the SFT I'm running in my 440 has more .050 (243/247) and more .200 int. (162 vs 159) duration than that particular roller (.200 ehx is the same at 164). The good old Ultradyne .904 lobes move pretty good.
I'm running 1.6 rockers, my gross lift is .586/.594.
So yours is a bit of a testament to how well the 270's and intake can flow without relying on big cam numbers.


Thanks plymouth67! Those are some stout numbers you're putting out, that's gotta be a fun ride!
Yours is looking great too.

My apologies to the A-body guys for "polluting" your forum with non A-body business. ;-)

 

[MOPARMAGA]

Actually, the SFT I'm running in my 440 has more .050 (243/247) and more .200 int. (162 vs 159) duration than that particular roller (.200 ehx is the same at 164). The good old Ultradyne .904 lobes move pretty good.
I'm running 1.6 rockers, my gross lift is .586/.594.
So a bit of a testament to how well the 270's and intake can flow without relying on big cam numbers.


Thanks plymouth67! Those are some stout numbers you're putting out, that's gotta be a fun ride!
Yours is looking great too.

My apologies to the A-body guys for "polluting" your forum with non A-body business. ;-)

That sir, is a beautiful challenger.
you don't have to apologize to us a body guys like were some lower class citizens lol.
I've read some good stuff, I personally have only gotten 5900 out of 240 heads on the Dyno.
I have a 470 that made pretty good power with a sft cam. It was making 600 ft lbs way down at 3000 rpm
I honestly think for a 512 a 270 tf is a pretty good size port , as in if Chrysler was smart and built us a max wedge 512 from the factory it would have worked well. The cars would not have held up very well though.
You wouldn't need a dp for anything.
If you ran the 240s and a track heat intake (if it fit) it will make plenty of power, a lot of low end too. The runners on that manifold are well designed & would be excellent for a 512.

 

[rikkitik]

That sir, is a beautiful challenger.
you don't have to apologize to us a body guys like were some lower class citizens lol.

Thanks!
I'm thinkin I'm the "lower class citizen", lol...
You guys are the ones stuffing big engines in light weight, tight places, and I come in invading your territory with my "mid-size" and moronic ideas.......

 

[MOPARMAGA]

Thanks!
I'm thinkin I'm the "lower class citizen", lol...
You guys are the ones stuffing big engines in light weight, tight places, and I come in invading your territory with my "mid-size" and moronic ideas.......

Lol, Mopars are Mopars to me of that era.
You have good ideas, you're starting with good parts and a badass car.

 

[plymouth67]

Thanks!
I'm thinkin I'm the "lower class citizen", lol...
You guys are the ones stuffing big engines in light weight, tight places, and I come in invading your territory with my "mid-size" and moronic ideas.......

Your all good!! Most everybody here are super cool and some great knowledge. I'm grandfathered in because besides my Challenger i also have an A body..lol

 

[MOPARMAGA]

Your all good!! Most everybody here are super cool and some great knowledge. I'm grandfathered in because besides my Challenger i also have an A body..lol View attachment 1716464055

Nice

 

[mbaird]

My 69 340 Swinger with a 4” crank and a 246/250 on a 108 will eat a Hellcat . Don’t see what the issue is.

 

[fishmens67]

My 69 340 Swinger with a 4” crank and a 246/250 on a 108 will eat a Hellcat . Don’t see what the issue is.

You lose once the speed gets over 120. lol
My fastback is capable of 150 mph+ with highway gears, problem is, aero and wind will push it off these plush Idaho roads at 120. lol

 

[mbaird]

You lose once the speed gets over 120. lol
My fastback is capable of 150 mph+ with highway gears, problem is, aero and wind will push it off these plush Idaho roads at 120. lol

Oh yeah ! I had my 70 Charger to 145 once ( calculated by rpm & gear) and it was floating.

 

[mbaird]

I have a 68 fastback as well that is getting a 408 and 46rh but I have no intention of doing those speeds .

 

[BSB67]

It would be great if the folks that have "Hellcat eaters" please post et and mph data too.

Thank you.

 

[AndyF]

Would a single plane intake trade-off some torque to help the trans live and add some power at higher rpm’s when he wants to race hellcats?

With an overdrive Tremec trans what is the ballpark for cam spec boundaries on a 470-528 stroker?

Yeah, you don't really need a dual plane when you have 500+ cubes so might as well pick up the extra power from a single plane. Also, if you pick a really good single plane the torque loss won't be that great when compared to a dual plane.
I have a 239/245 hyd roller in my 500 inch pump gas engine and that cam is one step too big for first gear driving. The car surges in first gear when you are below 15 mph.
For a street car with a manual trans I'd recommend smaller on the cam rather than larger. Too small is much easier to drive than too big, especially for a car that is going to be driven on the street.

 

[mbaird]

It would be great if the folks that have "Hellcat eaters" please post et and mph data too.

Thank you.

I have driven a Hell Cat and while impressive it still weighs 4600 # s. I have witnessed multiple well tuned muscle cars eat them . I sold a 2019 Acura NSX to a guy and watched it outrun a Hell Cat down the 1/4 . The NSX was not designed for drag racing and still beat it . I will add that Jack Beckman was driving it for Dan .
My brother whooped *** on a Hell Cat in his 68 400 Firebird that was stock appearing.
They are fast for a factory build but MANY members here have Hell Cat eaters . A yellow Duster comes to mind …

 

[fishmens67]

you don't really need a dual plane when you have 500+ cubes so might as well pick up the extra power from a single plane

I'd add the 440 to that thought.

 

[33IMP]

All these "hellcat eaters" kinda depend on the hellcats being stock, or stock-ish.
One of my last trips to Irwindale, there were three hopped-up Demons, and short of a full-on all-out race car...... no n/a 500" wedge is gonna be in the same area code.
The SLOWEST street driven Demon was a 5.70s car, the other two were 5.50s and 5.20s.
They would train length my nine second 2500 lb car, (6.30s 1/8), carrying two thousand more pounds.
On the other hand, I saw a claimed "1200hp" cat run mid 10s on a you tube short. A slug!

 

[BSB67]

I’m just talking plain-Jane Hellcat’s with good tires. Maybe it’s the tracks I go to, but I’m not seeing many warmed up street driven classic muscle cars knocking off 10 sec. ETs at 128 mph.

 

[TT5.9mag]

All these "hellcat eaters" kinda depend on the hellcats being stock, or stock-ish.
One of my last trips to Irwindale, there were three hopped-up Demons, and short of a full-on all-out race car...... no n/a 500" wedge is gonna be in the same area code.
The SLOWEST street driven Demon was a 5.70s car, the other two were 5.50s and 5.20s.
They would train length my nine second 2500 lb car, (6.30s 1/8), carrying two thousand more pounds.
On the other hand, I saw a claimed "1200hp" cat run mid 10s on a you tube short. A slug!

In the late model class at Irwindale there were a handful of hellcat/demon charger/challengers that were DAMN fast. The Escobar charger is a weapon!

 

[33IMP]

Sorry. Didn't mean to derail this thread, but.....
The 5.75 demon above, at a completely unrealistic weight of 4100 lbs with driver is making only about (an honest) 1150hp
The 5.20s car, with a realistic weight of around 4300 with driver is making almost 1600hp.
No offense, but will your n/a 500" wedge or hemi do that?
My 3500 lb car with me in it, would need a 700 hp n/a wedge, and a 300 shot to have a chance, at the slowest car. Reality can be a ***** sometimes.

 

[mopowers]

I'm really not sure what all was done to the heads. The intake has some porting done and the divider milled down about 1/2 ". Peak torque was 4700 rpm and peak horsepower at 5900. Carb is a Holley 850 DP.

Thank you. I may have missed it, but have you ever made it out to the track?

 

[plymouth67]

Thank you. I may have missed it, but have you ever made it out to the track?

No, I have not. In plenty of street driving situations my car keeps up with (I never said it would "eat" Hellcats) Hellcats....lol.

 

[rikkitik]

Sorry. Didn't mean to derail this thread, but.....

lol, no worries........
I think I'm going to ask a "what's the best oil" question next......
I'm only talking "normal-ish" Hellcats
I don't start sh**, but I swear, 392's, annoying crappy Fox Body Mustang's, Hellcats must "think" "old car, old guy = ez pickin's.
I can run pretty close with Hellcats, the others (depending on the mood) I usually just wave off...
And while maybe it's become "unfashionable", I'm okay if "my" car has a chunky idle, I dont need another "appliance". I like the giggle factor too much.
I'm pretty comfortable tuning (and living with) something down in the 10.5 in. vacuum range. I guess I had better, seems like that's where everything I build for myself ends up.......lol. (umm, going on 45+ years now).
Fact is, other than alignment, paint, and welding the 4 link, I do all the work myself.
That will continue with building the 512.
Maybe the 512 will run, maybe it'll be a turd (I'll bet it'll run though.......ooo, and it's actually my $$ on the betting line too, yikes). If I don't like the way it comes out, I'll change it.
If it's of any "reference", the vehicle that the Challenger replaced had 628rwhp 528rwtq, and only weighed 3100lbs. It most definitely saw WOT, and would also "pin your ears back".
That was the one vehicle that did have more than 10.5 inches of vacuum, lol.