IMHO, with a wide LSA like 112, it will be better since the low RPM overlap and reversion will be far less. Too much overlap/reversion will dilute the intake charge and make the low RPM torque weaker than the later intake closing. The extra overlap is only a blessing at high RPM's where the exhaust pull-through on the intake helps, but hurts at low RPM's.
Again..... depends on what the OP wants to do with the engine/car.
Advertised Duration (Int/Exh): 256/262
- Duration @ .050 (Int/Exh): 213/220
- Gross Valve Lift (Int/Exh): .454/.475
- LSA/ICL: 112/108
- Valve Lash (Int/Exh): Hyd/Hyd
- RPM Range: 1000-5500
- Includes: Cam Only
Part Number: 10200701
----------------------------
Wallace-predicted pressures@7.8Scr
240/248/112/20 overlap, ICA of 48*/135psi@sealevel; stock Mopar
>as above but corrected to 1200 ft elevation ......
129psi
256/262/112/35 overlap, ICA of 56*
/121psi@1200ft, stock 701Lunati
256/262/
106/47 overlap, ICA of 52*/
125psi@1200 ft, LSA tightened
EDIT: transferred in from post 39 for clarification
253/258/112/31.5 overlap, ICA of 54.5/
123psi@1200ft,
700Lunati
253/258/
107/41.5 overlap, ICA of 51.5/
126psi@1200ft, A/A but tighter LSA
More Edits, additional material.
IMO, with cams this small, reversion is ended before stall. You can tell by the very early vacuum peak
one more example to show what can be done.... at higher compression ratios;
268/276/110/60*overlap/ICA of 60/
159psi@1200@9.8Scr,Lunati 703. That's how you solve your soft bottom end problems with iron heads at 1200 ft, while simultaneously making some power, while sacrificing some economy, and enjoying a bit of idle lope at 700rpm.
The 702Lunati has compression and power events only 3* different from this 703, but the overlap is reduced to 41* so you lose the slight powerbulge after the torque peak that headers would make, making log manifolds an option.
(262/268/112/41*overlap,ICA of 59/
160psi@1200@9.8Scr, Lunati 702.)
Hiway economy will be very little changed so personally I would chose the 703 over the 702 every time.
And then, for even more power, while retaining bottom end; there are the Solid Flat Tappet cams
Here is the smallest SFT Lunati makes, installed in your 7.8engine; the Lunati 740
264/272/110/48*overlap/ICA of~54*after lash/
123psi@1200ft@7.8Scr .. This is a 235/243/110 @.050 so pretty big in terms of power, yet a modest overlap which after lashing will be even less.
Lets bump the compression up a tad and see what happens; At 9.5 Scr the pressure climbs to 161 psi, and the bottom end is over 25% stronger than 700Lunati@7.8. To understand that 25%, think 4.10 gears versus 3.23s on the start line. or 175ftlbs versus 140 at 1750stall.
I'm not telling you to completely re-engineer your combo. This info is for the next guy, beginning his teener build and clicks on your thread using the search button.
The 700 is 253/258/112/31.5/Ica of 54.5* and 208/213@.050/
123psi@7.8Scr.
The 740 is 264/272/110/40(estimated after lash) and 235/243@.050/
160psi@9.5 Scr with an estimated ICA of 54*after lashing.... The ICAs are nearly identical.
I imagine the power difference might be 40hp. That would be ~40hp for the cost of a set of pistons, and setting up the heads to run the lift. And don't forget; plus 25% stronger bottom end, over the Lunati 700. So maybe you save the cost of gears and a hi-stall, and so burn less gas around town. So the net cost could be less than one might imagine. And a lot less at the end of the year.
