Yea, it is lengthy and I haven’t typed it in awhile so...... ha ha ha
Horsepower limit for out of the box Edelbrock RPM heads
- Thread starter Es65Coronet
- Start date
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gzig5
Well-Known Member
I'm more interested in engine responsiveness. When you are driving a road course or cone event, the engine spends a lot more time back and forth in the mid-RPM band than it does in the top 1500 rpm. The the throttle isn't wide open all the time. An engine that is dead below 4000 rpm might work for a drag car with a 5k converter, but isn't going to pull the car out of a slow speed corner very well. Obviously the "package" has a large effect on the performance, but it is difficult to pick a gear that is going to be perfect but I think a 3.55-3.91 is the likely choice until/unless an OD manual can be funded. There is a limit on how much gear you can run and still drive it to and from the events.
Pretty crazy we are sitting here talking about 400, 500, 600 horsepower small block engines. It’s a great time to be a Mopar lover
Hemirunner
Well-Known Member
For sure. I think with a solid roller for more rpm and a bigger carb, I could have hit 700hp on pump gas with that Victor headed R3 pretty easily. I’d do more small blocks but I hate that 59 degree lifter angle. Mopar should have ditched that disaster for the LA platform.
nm9stheham
Well-Known Member
It's a great time to be ANY American V* lover.... parts galore compared to 30-40 years ago. 350-400 used to be darned good for a home builder LOL.
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nm9stheham
Well-Known Member
Weight on the front end is a bad, bad thing in road racing, rally, auto-x. I'd far prefer a small block with AL heads and intake to drop 100 lbs off the engine and front end weight. Weight is always a big enemy in cornering, and, besides, you can easily get RWD torque to exceed the available traction while cornering (which is lower than straight line traction) with a small block these days, in all gears except maybe the top one. So the big block is a poor choice unless you are on a wide open course with long straights.
Hemirunner
Well-Known Member
My only road racing experience is a Lemons race in a Honda Accord, but I really don’t think a big port in a low rpm engine is a good combo for that! Lol. You’d better swap in a Hellcat Hemi!!
nm9stheham
Well-Known Member
FWIW..... My experience is a qualified 'yes', based on my long-ago builds of a 351C and a 1.6L Mitsubishi, where that wide range flat performance was desired. Both had what would usually be classified as 'too big' on most or all of the flow parts (heads, intakes, headers) for low RPM use, but the cam selection in each case was small-medium and the static CR kept up. The cam and SCR/DCR made the low end 'fully awake' to or below 2500 RPM and the large flow parts allowed them to still wind out with good torque to 6000 RPM or so, with optimum shift points on both engines right at 6500 RPM.
Sure, neither had the peak HP that COULD have been accomplished, but both did what was desired. The 351C was an all around cruiser/street racer/tow vehicle/daily driver that would beat factory 4 BBL 440's with a 3.08 rear gear every time, yet cruise at 18.5-19 mpg on the interstate, with a standard C4 trannie & stock TC. The 1.6L was a rally engine, and was one of my favorites; you had the torque you needed all over the RPM range, and in a light Arrow body, was the equal of much larger engined rally cars.
Now for this type of use, in the 300-360 ci engine range, I've never done one with the 300+ cfm sizing of ports in a small block V8 to see if that would push it 'over the edge' at the low RPM's: IO doubt I wil ever get the chance. But that 1.6L had cut-down 327 valves and had been ported out the wazoo, and flowed in the 'near-stock-hemi' range, per the porters (who did Bob Glidden's Ford heads LOL), so for a 1.6L, it's flow was in 'Victor-equivalent' land. Yet, it was fully up on the torque curve at 2500 RPM, with twin 40 Weber side-drafts and medium sized headers. The cam really set the performance and was one from the Direct Connection C2 package line specifically for rally use.
Something in the 250 flow range for this type of engine in a 300-360 ci engine is pretty adequate, IMHO, and I would not go smaller if I wanted a responsive range up to 6000 RPM's or more. Cam and carb selection become more critical IMHO with large flow parts to keep low end torque. And EFI becomes a big plus.
Yow! Great line of posts.
What I have noted is very much the same as you wrote. Not as varied in small displacement engine. Just in SBM engines. What I have noticed (at the risk of repeating myself and NM9,) is a good head and a medium/smallish cam with a good compression ratio will power a car very well from down low to way up top.
I’d link an engine masters video (episode 19 IIRC) but many may have an issue viewing. But in short, these guys did a not so small, small block with a small cam and well ported heads on a 372 engine. The Hyd. roller cam w/224 on the intake had its power band extended a good bit (500+ rpm) and made 470 hp. Same build as the wife’s car though the displacement and how it was set up is a good bit different than the wife’s.030 over 360. There Chevy engine was a big bore/stock stroke combo.
(3.48 X 4.125 Chevy vs the SBM 3.58 X 4.03)
That looks like a barrel of fun.
But I have to ask, not that I think your crazy or anything, but did you want to put that Hellcat HEMI in the Honda?
Again, not that I think your crazy but I want pictures to copy the build. Think about!
Run silently down the road, talk trash, stomp the pedal and open up the dumps!!!!
Now how cool would that Honda become?
You could potentially STOMP OUT Demons!
What I have noted is very much the same as you wrote. Not as varied in small displacement engine. Just in SBM engines. What I have noticed (at the risk of repeating myself and NM9,) is a good head and a medium/smallish cam with a good compression ratio will power a car very well from down low to way up top.
I’d link an engine masters video (episode 19 IIRC) but many may have an issue viewing. But in short, these guys did a not so small, small block with a small cam and well ported heads on a 372 engine. The Hyd. roller cam w/224 on the intake had its power band extended a good bit (500+ rpm) and made 470 hp. Same build as the wife’s car though the displacement and how it was set up is a good bit different than the wife’s.030 over 360. There Chevy engine was a big bore/stock stroke combo.
(3.48 X 4.125 Chevy vs the SBM 3.58 X 4.03)
You competed in the Lemon race?!?! Get out!
That looks like a barrel of fun.
But I have to ask, not that I think your crazy or anything, but did you want to put that Hellcat HEMI in the Honda?
Again, not that I think your crazy but I want pictures to copy the build. Think about!
Run silently down the road, talk trash, stomp the pedal and open up the dumps!!!!
Now how cool would that Honda become?
You could potentially STOMP OUT Demons!
MopaR&D
Nerd Member
Interesting post, when I called Jim at Racer Brown for a custom grind and told him I intended to ultimately road race the car he basically explained what you just said. Peak power won't be as important as having instant throttle response and a wide power band to shoot the car out of the corners. "You're gonna be mashing that thing all the time at different RPMs and you want it to pull hard every time," or something along those lines is what he said.
Ill take a 360 and 300 plus cfm heads any day of the week. Mild 600 lift roller and 6700 rpm shifts are golden.
Hemirunner
Well-Known Member
No hemi in it, but I could pull off that swap!!Yow! Great line of posts.
You competed in the Lemon race?!?! Get out!
That looks like a barrel of fun.
But I have to ask, not that I think your crazy or anything, but did you want to put that Hellcat HEMI in the Honda?
Again, not that I think your crazy but I want pictures to copy the build. Think about!
Run silently down the road, talk trash, stomp the pedal and open up the dumps!!!!
Now how cool would that Honda become?
You could potentially STOMP OUT Demons!
nm9stheham
Well-Known Member
EXACTLY! You need smooth, wide torque to make the brain-to-foot-to-rear wheel control of the torque on the rear tires wholly predictable so it becomes a muscle-memory control for the driver. Plus to make sure you always have a gear that will work, whatever the speed. That's is all to get the right slip on the wheels to throttle steer, as well as to get a good launch out of every corner. You eventually run out of torque at the higher speeds, simply due to the lower trannie gear ratios, and have to change your driving style. That is where a big block's torque would step in, and be of use on the higher speed, wider open courses.
And if I can be forgiven..... this all becomes 'moreso' in rallying, where every one of the thousands of corners in an event are different.
It becomes a quest for car control with the throttle over raw power, and you don't have that throttle control if you don't have adequate torque at the drive wheels in all conditions. So you either build for a wide torque band, or put in a 6, 7, or 8 speed trannie with electronic shifters, like the top end rally cars of today have.
Once again... application drives the engine design.
I like your thinking!
gzig5
Well-Known Member
Functional hood scoop?
gzig5
Well-Known Member
Exactly. I've been driving a 2000 BMW M5 for the last ten years. It's obviously much more modern technology, but it it's 5.0 liter V8 tops out with 400hp at 6500rpm, but it produces better than 360 lb-ft of torque from 2500-5500 rpm. That motor really can launch that 4000lb car out of the corner with it's 6 speed manual. I'm hoping to find a cam/head combo for my 340 that will emulate that profile and better the numbers. That would make the Cuda a real handful.
M5 chassis dyno.
MopaR&D
Nerd Member
In the past decade or so car companies have focused heavily on maximizing torque at all engine speeds, they all advertise "90% of peak torque available from 2000-6500 RPM" or something similar. Modern cars need it considering they're so fat and heavy.
My mom's 2014 300C with the V6 and 8-speed has the same 0-60 times as her older 2009 5.7 Hemi 5-speed. You only notice the difference at freeway speeds when the gearing can't really help anymore. It's a real rocket off the line though I love messing with the local import tuner d-bags they never see it coming lol
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Yeah my wife's DD is a 2014 Chevy Orlando 2.4VVT with a 6 speed auto. Orlando is a crossover/hi-roof wagon.It appears to be a 108wb/3650 pound unit, just like my Barracuda. And if I wind it up (6700 redline) she rockets thru 2 gears and does pretty good in third too. When I go to pass someone, it kicks down 2 cogs and and the VVT comes on line; moving her out fairly briskly. And the 65=2000rpm makes ~32mpgUS,which is easy on the wallet. I never notice the dead at 65mph, cuz it kicks down at just the right amount of throttle, yet never hunts for loc-up.
Nice combo.
But the heater blower motor just cost me $195C, and the control module for it was $159C. Easy installs tho. And the stinking cartridge oil filters cost $9C apiece! The cabin filter was $80C,yumpim-yimminy.
But I thought I was pretty smart; before I drove it off the lot, I got the used car dealer to throw in a spare set of 15" mags and 4 new tires. 15" tires are cheap. So I should be good for 5 or 6 years on that score, which will put me into my 70s, hopefully retired not driving much anymore, if the world makes it that long.
Nice combo.
But the heater blower motor just cost me $195C, and the control module for it was $159C. Easy installs tho. And the stinking cartridge oil filters cost $9C apiece! The cabin filter was $80C,yumpim-yimminy.
But I thought I was pretty smart; before I drove it off the lot, I got the used car dealer to throw in a spare set of 15" mags and 4 new tires. 15" tires are cheap. So I should be good for 5 or 6 years on that score, which will put me into my 70s, hopefully retired not driving much anymore, if the world makes it that long.
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Wyrmrider
Well-Known Member
Study the engine master builds
another problem with a too big cam or "BOSS" style heads is the engine coming "up on the cam" and swapping ends coming out of a corner
not a fun way to drive unless you're AJ Foyt, also a very common problem with sprint cars when som novice builds a motor like a pro driver has
(really long pedal travel and progressive helps)
another problem with a too big cam or "BOSS" style heads is the engine coming "up on the cam" and swapping ends coming out of a corner
not a fun way to drive unless you're AJ Foyt, also a very common problem with sprint cars when som novice builds a motor like a pro driver has
(really long pedal travel and progressive helps)
A408Cuda
Well-Known Member
In response to the original post I've got stock RPM's on my 408 and it dyno'd at 489 hp at 5600 and 523 tq at 4500, 10 to 1 CR The specs on this cam are .566/.578, dur @ .050 244/248 with a 108 LSA. Dyno was done with a 750 quick fuel and long tubes.
The big big picture is the dyno tells us one story and the track tells us the truth. That’s why I never waste money on dynos. I would rather spend that money towards “real horsepower”. Like maybe a better set of heads, ported heads, ported intake, etc, etc.
turbodart68
Well-Known Member
I agree to a point. The dyno is a good tool but its not for comparing one engine to another. Watch the 408 shootout on Engine Masters show from Motor Trend on Youtube to see that the Edelbrock head is pretty much a copy of the stock small block Mopar head. 170cc out of the box.
MopaR&D
Nerd Member
I will probably chassis dyno and tune my Duster just because i've never done it before and I'd like to see how a pro tunes it for max power. Also I no longer live 15 minutes from the drag strip now it's more like 90 minutes away, the shop I go to for machining and dyno stuff is only 25 minutes away. Plus I know the guys who run that shop pretty well they're really cool and work on legit 8-second cars and 1000+ HP engines like it's just another day in the office.
tasvalowna
Well-Known Member
Ive got a 408 with eddy heads . The porting is stock but they have larger inlet valves 2.08 from memory . It dynoed 515hp and 535 ftlb.its running a 750 holley and dual plane inlet with a howard hydraulic roller. Ive ran 11.2 at 120 in a street car through a 727 and 3.9 gears.i would dearly love to run an 11 flat . Will a port job get me there ? Im in australia so theres no cnc program that i can find for my heads . I know a fair few stock eddy heads on 408's that are around 450hp and that seems to be the norm.
No, porting would probably not get you an 11 flat...it would probably put you in the high to mid 10's. My previous motor was a 410, small street roller, and stage II ported Edelbrocks from Ryan at Shadydell speed shop. It ran mid 10's.
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