Making a Street Hemi REALLY run?

[Ghoste]

We all know how much technology has made the wedge a dollar smart way to go but since this is the bench racing forum and I'm bored, what do some of you think it would take to make a Street Hemi really run.  As much as we might not like to admit it, our vaunted Hemi frequently got it's ass kicked on the street.  Now I understand the tuning issues which made these engines difficult at best for the average enthusiast to run, but what would it take to really make them scream?

[firefighter3931]

More cam and more displacement.   Or you could just throw a blower on it and really watch it fly....the hemi head was made for forced induction. 

Ron

[Blown70]

More cam and more displacement.   Or you could just throw a blower on it and really watch it fly....the hemi head was made for forced induction.  

Ron

I agreee   

528 enough displacement?

[firefighter3931]

528 enough displacement?

Ya, that should do it !    

Ron

[Ghoste]

So you think the Street Hemi as it comes from Chrysler is basically a doomed pigeon?  Nothing short of monster motors or blowers can make them run hard on the street?

[Blown70]

Well I would say that proper cam with, Timing, carburation, and Headder.  I think you could TUNE it into a great one.  However,  I do not work on them all the time so.... I am speaking out of my orface here.

Just my two cents.

Tom

[Chryco Psycho]

better carburation helps too , a cross ram & a pair of modern Holleys or Demons will definatly be noticable !!

[Ghoste]

So basically, the only way to turn a Street Hemi on is to take out the street portion and get over it?  There is no such thing as a Street Hemi, there was a Race Hemi, an Out Of Tune Hemi, and if you did your homework you could make a Streetable Hemi?
This is maybe what I was wondering if I would get out of this.  I've always maintained that other High performance engines were passenger car engines hopped up for racing so even if they were out of tune, they still ran like the regular mill.  The Hemi was a race only piece that Chrysler detuned for the street so it would only need a couple of specs off to run like a bag of wet dog turds.
Neil, have you had much experience with rebuilding Hemi's for race or street?

[firefighter3931]

The problem i see with the street hemi is a big intake port relative to the engine's displacement. This creates low intake airspeed/velocity and makes the engine feel soft down low. That's why you hear of old street hemi racers talking about the Hemi coming on so strong on the top end. Basicly you had to rev the crap out of them to get it into their powerband. A little extra stroke and displacement helps to compensate for a head that is arguably too large for 426 cubic inches. On the street, it's all about port velocity. A smaller, more efficient port will always be more responsive than a big, lazy port...that's just the way it is.  

Ron

[Ghoste]

Sooooo, going away from streetability again (and we're just playing here, I know streetable and REALLY running are seldom if ever compatible), another approach for a Street Hemi would be minimum 3000 stall for an automatic and nothing higher than say, 4:56 gears?

[firefighter3931]

another approach for a Street Hemi would be minimum 3000 stall for an automatic and nothing higher than say, 4:56 gears?

Yep, that would work but you'd need to spec out the cam for the right poweband. This type of motor likes to rev and with those gears it would. If i were doing something along these lines it would be a solid flat tappet cam....hydraulics aren't too happy beyond 6000 rpm.

Ron

[Ghoste]

Do you feel the Street Hemi cam is too much compromise for what those engines need then?

[firefighter3931]

Do you feel the Strret Hemi cam is too much compromise for what those engines need then?

Absolutely....a 250*@.050 solid is what i'd run with those gears and that stall.

Ron

[Ghoste]

Reinforcing then, that there can be no such thing as a Street Hemi.

[Chryco Psycho]

I have built a few Hemis , they definatly respond well with some more agressive parts
the street Hemi was really just built to satisfy Nascar & other racing sanctions by making a production street engine , the street version is a big compromise the Hemis love to run all day between 5000-7500+ rpm
I have found a couple of cams that work well in the street Hemi , keeping it livable but still with great power

[69fuchs]

link to a 600 hp stock stroke, stock bore, pump gas street hemi, with 9:1 compression.



http://moparmusclemagazine.com/techarticles/155_0310_hemi_426_dyno_test/