Posted By: 70Cuda383
108 LSA vs 107 LSA - 12/26/10 01:35 PM
I'm looking at a hyd. roller cam for a 360 cu in motor with Magnum heads, dual plane rpm intake and a carb.
looking at hughes "whiplash cams for magnum motors w/carbs"
they have one thats .544 lift, 222 degrees at .050, on a 107 LSA
how would this run compared to a similar cam that was custom ground, that's .566 lift, 214 degrees duration, and on a 108 LSA?
what would be the characteristics of each one?
trying to decide if the 2nd custom ground cam would work well for me, compared to the "hughes, custom cam for carb'd magnum" cam.
especially at half the price!
Posted By: MR_P_BODY
Re: 108 LSA vs 107 LSA - 12/26/10 02:30 PM
A shorter LSA has more overlap and has that choppy
idle... both of the cams will be a low rpm cam
Posted By: 70Cuda383
Re: 108 LSA vs 107 LSA - 12/26/10 02:44 PM
from my limited understanding, the longer duration cam will be higher in the RPM range, right?
Posted By: ahy
Re: 108 LSA vs 107 LSA - 12/26/10 02:55 PM
The longer duration cam should run higher in the RPM range from my also limited understanding. One thing to check, the stock Magnum valvetrain seems to be good to about .5" lift. Upgrades to springs, seals, studs ect. are probably needed with either of those two cams. The .566 lift version looks like its a very fast rate cam... I'd make sure the stock hydraulic lifters can handle it with required springs.
Posted By: Sport440
Re: 108 LSA vs 107 LSA - 12/26/10 08:52 PM
The Difference in the 8* duration @ .050 will be far greater then the 1* in LSA
But, 1* tighter LSA is on the bigger cam, witch normaly increases overlap.
But, not in this case as the smaller cam installed stright up @ 108* ICL will not open the intake valve untill 1*ATDC The exhaust will close at 1* BTDC So theres a 2* spread from Overlap "EDIT Stated @ .050 dur."
The bigger cam will have 8* overlap vs none of the smaller cam.
At the same spec ICL the 222 will close the intake valve 38* ABDC vs the 214 @ 35* ABDC
Of the two I dont know whitch one Id pick. Probably the smaller one because you said 3900# and towing. The bigger one would would most likely work just fine too mike
IIRC stock mag heads dont take much lift over the .450/.465 lift mark
best measure clearance on the valve guide/retainer/seal to make sure you have enuff clearance for that lift range
Posted By: 70Cuda383
Re: 108 LSA vs 107 LSA - 12/27/10 04:18 AM
I never said towing. I did say truck, but not towing. it's never going to tow, and is a street cruiser. it's just a heavy street cruiser!
as for the lift issues on stock heads, the cam with the 107LSA is from Hughes, and is advertised as "a hyd. roller cam for a magnum engine with a carb instead of EFI" and says that all you need is their springs and retainers, and it will work on an otherwise stock magnum engine...and is infact, designed specifically FOR the stock factory Magnum engine--Head flow, compression ratio, etc.
The other cam is a custom grind Magnum cam, but the guy was using it in a 408 stroker, and his heads were worked.
Posted By: Sport440
Re: 108 LSA vs 107 LSA - 12/27/10 05:11 AM
Well, with that info Id go with the bigger cam 222 @.050 and 107 LSA and the retainer/spring package from Hughes.
You wont be able to use the other higher lift cam unless the Magnum heads have been previously machined by somebody else or you for more clearence for .550 lift and above to be safe.
From what I hear, the Magnum heads are are definate great upgrade from the older heads for the SB, from the X, J, and the 308 heads.
mike
Posted By: 70Cuda383
Re: 108 LSA vs 107 LSA - 12/27/10 05:29 AM
that's kind of how I've been leaning, since the Hughes cam was designed specifically for a stock stroke magnum engine, vs the other one being designed for ported and worked heads, and a stroker 360 at 408cu in.
the factory 5.9L from the trucks is exactly the same as the 300hp crate motor, they just replaced the EFI manifold for a carb manifold, and replaced the distributor, so that right there is a 50 hp jump from the "production" engines.
the 380hp engines were just different pistons for higher compression, and a different camshaft, again, stock magnum heads.
I figured with just a cam change, I'll fall somewhere in between.
...nowhere near as fast as the truck was with a 383 stroked to 438 with eddy heads and a TKO w/ 4.56 gears in the back, but...it should do alright for a street cruiser.
Posted By: MR_P_BODY
Re: 108 LSA vs 107 LSA - 12/27/10 05:48 AM
I think I would go with the 544...
222@50 because
I believe either one is short on revs but this one will
hang on a bit longer... they both would have lump to
the idle
Posted By: 602heavy
Re: 108 LSA vs 107 LSA - 12/27/10 04:38 PM
Comparing these two cams @ .050 duration is really a crap shoot & does'nt tell you anything , seat to seat timing #s will give a better idea on how these camshafts will behave (.004-.050") , could be chalk & cheese.
Depending on intensity #s the smaller stick may be longer @ overlap & be a dog down low.
Posted By: S/ST 3040
Re: 108 LSA vs 107 LSA - 12/28/10 01:24 PM
No recommendation but, thought I would point out:
LSA is given in camshaft degrees meaning, 107º would require
214º of crankshaft rotation from EX c/l to IN c/l.
108º LSA would be 216º @ the crank.
Identical lobes on a 107º and 108º LSA would change overlap value by 2º, not 1º
(keeping in mind a stock truck converter, stall around say, 1800-ish? 4200 lb truck, 3.92 gears with 28" tires0
