426 Crate Hemi Street Cam Suggestions

[Tony K.]

Hi,
I am in the rebuilding stages of a Mopar 426 Hemi Crate engine circa 2002. It will be going into a 1966 Belvedere II Hemi clone. The car has a Dana 60 with 3:54 gears, stock hemi exhaust manifolds, 4 speed manual, and 14" tires with dog dish hubcaps. The motor will be 9:1 compression ratio, stock mopar iron heads, and reproduction dual quad intake with two 600 CFM edelbrocks. Car will be almost 100 % street driven, just looking for that great Hemi sound at idle. Does anyone have any cam suggestions?

Thanks in advance for your input,

Tony K.

 

[Tony K.]

Some eye candy for your efforts.

 

[wyrmrider]

post up what you think the head flows are
Hyd, solid FT, hyd roller, roller?
adj rockers?
have you measured and hand calculated the 9:1?
let the mufflers give you the Hemi sound
are you up to a hyd roller? FT? Hyd?

 

[snakeoil24]

forget hydraulic roller in hemi your going to break stuff stay with solid roller..

 

[not so famous bob]

post up what you think the head flows are
Hyd, solid FT, hyd roller, roller?
adj rockers?
have you measured and hand calculated the 9:1?
let the mufflers give you the Hemi sound
are you up to a hyd roller? FT? Hyd?

stock street hemi heads flow close to 400 to start with,, hi 300 something------------

 

[TetanusShot]

Not a suggestion, just some data to add in your search:

Stock iron '70 heads, True 10:1, Comp 24-300-4, installed straight up, safe with 93 octane. Stock converter, street car.

Its nice and all... but wish I had gone with a bigger cam. Good luck with your search.

 

[Tony K.]

post up what you think the head flows are
Hyd, solid FT, hyd roller, roller?
adj rockers?
have you measured and hand calculated the 9:1?
let the mufflers give you the Hemi sound
are you up to a hyd roller? FT? Hyd?

Looking for Hydraulic flat tappet. Going off the machine shop for the 9:1.

 

[wyrmrider]

thanks Hyd Flat tappett
do you have adj rockers?
what pistons- just that 9:1 is low but can work well
Tetnusshots solid lifter cam is 235@.050 .0331 cam lift around a half inch valve lift called a 270 class cam close to stock
The Purple Shaft Hemi grind was 284 Mopar degrees (compare to stock)
Went strong after it got to 3000 rpm but not so much down lower. 3:54 about the minimum 7-8 inches vacuum
Stock Hemi Hyd was 278 Mopar degrees also about 236@.050 if my notes are correct
rule of thumb One Mopar size larger than stock works as far as duration (torque curve) bigger than one Mopar size costs 60 foot time (not your problem with street time but driveability)
Larger than one direct connection size larger required converter and or gear changes to restore the first block time-
larger than one size picked up quarter mile et and mph but only on the last 8th mostly
http://www.hotrod.com/articles/mopp-0310-hemi-426-crate-engine-dyno-test/
looking at dyno run one (T1) where do you want more torque? (wish they had shown 2000 up)
remember a cam for stock exhausts is completely different that with headers- through the mufflers and both different from open headers

 

[Hemirunner]

thanks Hyd Flat tappett
do you have adj rockers?

All G2 hemi rockers are adjustable, even the stock ones.

 

[wyrmrider]

Thanks
I couldn't remember
we ended up using different stands and rockers with increased lifts 2" valve springs
got accused of cheating- can you believe that?

 

[Hemirunner]

Thanks
I couldn't remember
we ended up using different stands and rockers with increased lifts 2" valve springs
got accused of cheating- can you believe that?

We always read the rules looking for what they don’t say rather than what they do say....

 

[wyrmrider]

I guess we need to know what springs your heads can take, or how much lift you can have or want
I'd suggest that based on what was posted above with 9:1 instead of 10:1 you might want to keep the intake duration a little lower, exhaust comes later
here are some cams in that range-
notice increased lift therefore area under the lift curve makes a lot of difference compared to stock or a .480 lift cam
recommendations look ok to me
there are cams and there are lobes
Hemi lift Lobe lift duration duration@.050 @200

Hughes 518/509 330/335 216/220 Hot daily driver

Howard .332 263 216@.050 136@.200

Hughes .525/.524 .335/345 220/224 3.55 stock HP to mild stall one step up from stock

Howard .337 267 220 140

Hughes .541/546 .345/353 224/228 stock to mild stall 3.55 hotter than stock daily driver

Howard .345 271 224 144@200

Howard .353 275 228 149 hot daily driver 2800 stall 3.70 gears

Howard .556/538 277 230 150 @200 2500 stall / gears 2200-5800

Howard .502/.486 lower lift version 231 headers gears 2500 stall

XE275HL 351 275/287 231/237@.050 149@200 110lca Ic gives 64ABDC

XM 5962 356 279@ 235 153@200

Voodoo .342 279 234

P4349259 .5 lift (278) 236

MP5155618 .502/.486 (278/278)

MP4529315AAE .484/475 284/284 241/241 idle to 5800 mechanical flat tappett AE is HYD ???

Howard 370/.375 285/289 238/232 3.91 gear 3000 converter high compression

XM5965 .363 285 241 159




Bullit (not Ultradyne) also have as do Crane and Engle

 

[Challenger340]

If an early 2000's vintage 426 Crate Hemi, most probably nowhere close to actually 9:1 using the contract Wiseco Forgings as delivered..... just saying, mock up and pour an actual Dome Downfill Volume for yourself.
Don't guess on the Head Flow, get them Flowed as results can vary widely depending upon even the seat prep.... and you wish to maximize area under the curve for best result on the small 426 Engines, because they don't pull the Head real hard at early lifts versus the relatively big port volumes.

 

[wyrmrider]

which is why you do not want to open the Intake too early or you get port stall
you only want it enough to build velocity and keep building it while piston accelerates down
but then open it fast enough to have it really open by the time piston reaches maximum velocity
lower compression hemi is not going to want a bunch of overlap
stock exhaust manifolds you do not get enough suck on the exhaust to pull the intake in- cam has to be different with headers even with headers through the mufflers