My 383 short motor is on its way and Im keen to hear some cam selection advice, it will have an 8 week Pacific cruise before it gets here and I will have to buy the cam and other parts during that time.

I have read plenty of other threads and dont want to hear the usual LPE or ZZ recomendations, due to budget constraints I will have to buy everything I need (cam,lifters,timing set, gaskets etc) form one place due to shipping cost to australia, so Summit is my only real option.

My 383 will be 11:1 comp, using my Edelbrock CNC 180 heads, ported and siamesed SLP, the usual mods (as listed in my garage) with a 3200 rpm stall and 3.07 rear. I want to use the car to do Hillclimb events (700 metres uphill / 6 bends) and as a cruiser so it needs to be streetable. Looking at hydraulic flat tappet (its an 85)

I want to hear about 110 v 112 LSA cams in a modified TPI,
Im thinking around .500 to .550 lift (with 1.6 rockers)
a lot of the cams in this range have 230 to 240 something duration at .50, is that going to be ok ?
Also what do people think of split pattern, which Lunati seem to like, currently I have the Lunati 112 LSA, 219/227 duration and 500/520 lift with 1.6 rockers, other manufacturers such as Howard, Compcam and Crower dont have split or only a small amount, is it a benefit in a TPI to have the larger lift and duration on the exhaust or is this dependant on how much it is modified ?
I want it to be a torque monster that will run hard to 5500 rpm

 

112 LSA easier to tune than 110 on EFI ( depends how good the tuner is )

Split duration relates to the head I/E ratio
http://www.chevelles.com/forums/showthread.php?t=191657

Popular 383 cams ( hyd rollers ) are 280XFI (230 / 236 ) and Crane 119661 (230/238 )
Depending on what rods are in your engine you may need a small base circle cam so the rod bolts don't hit the cam

 

Plus, 230-240 duration is more than you want/need with a 5500 rpm engine. You want/need max TQ -- while generating HP to 5.5k. That happens when the valves are closed.


What do the heads flow?

Did you see the results of TA's build (before dissing the popular choices)?

 

First off Lobe Separation dosen't mean squat without the proper context... The camshafts Seat Timing (Advertised Duration), and Intake Centerline are as important (actually more so) to determining drive-ability and power band.

Split lobes between the intake and exhaust are commonly called dual pattern cams... where as a cam with the same lobe is used on the intake and exhaust are called single pattern cams.... It's commonly known that single pattern or dual pattern cams with less split (IMO less than 8*) make more TQ but have a shorter power band than dual pattern cams with more split.... increasing the exhaust duration over the intake duration typically gives the engine more over rev capability past peak power, allowing power to hold on a little longer... This is because the bigger exhaust lobe opens earlier and closes later.... you can accomplish the same thing to a smaller extent by running a wider LSA... like going from a 110 to a 112.

Honestly I think you have too much stall converter. With a 3.07 gear, those tiny cyl heads and modified TPI intake on a 383 - Your BEST power band use-age is going to be idle to 5000RPM....

Since you are set on a Hyd flat tappet, I think the Lunati you have listed is a good choice.

Others to look at IMO -

Howards PN 112571-12S
Comp PN CCA12-238S

All 3 of those cams will make power past 5000RPM where your intake and heads are going to sign off. They are all very similar and I don't think there would be more than 5HP between any of them.
Will

 

I ran a 383 for years. I would suggest you spend the extra $$$ and move up to a hydraulic roller cam. It will open and close the valves quicker. The cam will be more versatile and will pull stronger from lower rpms to where you want it to stop. You will have less friction and won't have to worry about cam wear. I was running 10.4 compression and ran a Crane 222 230 hydraulic roller with .575 lift. Great torque and power too. A good set of heads is important. For your needs, do not overcam the motor. 230 240 is way too much. I run that cam in my 406 and spin to 6700.

 

Im running a set of Dart Pro 1 (180) heads on my (10.25 to 1) 383 motor..The cam Im running is an Erson 218/226/112 roller with 1.6 rockers. This cam seems about perfect for my combination and is very close in specs to the Linginfelter 219 and the Hotcam.. There's a reason that alot of guys having motors setup like ours are running these cams........WW

 

Thanks for your responses guys, much appreciated, it seems like when you ask a question you get even more thrown at you, so in reply,

Vettoz - thanks for the link, there is a lot of good info there about what cam profiles do,

Gregg - my heads are actually 185's the flow figures are .400 231/185, .500 250/199, .600 254/203,

Rklessdriver - the 3200 converter was recommended for the application and for future mods, as it was custom made here Im in to it for a lot of money including the fitting and there is no chance of changing anything now.

383vette - yes i hear you about changing to roller, its just the extra expense but i did some looking and summit have a Compcams xtreme energy retrofit cam/lifters kit, 112 lsa, 224/230 duration, 500/510 lift with 1.5 so 530/540 with my 1.6 for $475, might have to keep saving !

 

I should have asked about the intake (flow) as well. The degree of siamesing and base play a factor too. Though you've specified a 5500 rpm power "limit", the choice of a 3200 stall implies a future installation of a short-runner intake (or heavily siamesed intake).

Were you thinking of a large duration cam that's installed with an advanced orientation? Typically, increased overlap with advanced orientation can emphasize power in a narrower, peakier powerband. Advancing the cam timing pulls the powerband down lower.

 

X2. The 219/227 lunati wouldnt be a bad choice given the gearing and small heads/restricted intake. Given the 3200 stall and if you siamese the runners more, i would actually gobnext step up which i think is the 227/233? I like this cam as it will allow power to hang on after peak, as the intake and heads restrict the motor. This will extend your shift point and get more out of the converter which is a tad bit high. Id rather see 2800 to take advantage of where the tpi combo will start making good torque. Come off the corners harder if it hooks up. And the extended power band up top will allow you to hold gear longer which may be necessary in hill climb events if there are short straights.

110 lsa should have more mid range while 112 and wider will favor broader top end curve. I dont think it will make a big difference either way. Both will be easy to tune, they arent big cams. Only concern is the 85 ecm is not real easy to work with. 86-89 maf systems are better.

 

Ed Wright at fastchip.com is the man for 85 vett tuning. he did my 85. im running 239/ 244 530 lift. no one even wanted to tune my 85, then i found Ed.

 

I have only done basic porting and siamesing so far, Im talking 5500 coz thats what it will pull now going up the hill, I can see the tacho graph in the gopro footage, I can do a bit more work on the inlet while it is apart,
advancing the cam is something I will have to consider for my application, are you saying you can get away with a longer duration cam if its advanced ?

 

I am currently using the lunati voodoo 219/227 - 500/520 in my 350 and it revs to 5500 up the hill pretty well, my original plan was to re use this cam in my new engine, but after speaking to an engine builder he said dont put a used flat tappet in another block, and i can understand why, so i need a new cam, and naturally everyone wants bigger dont they ??
As i posted earlier i found the compcams xtreme energy roller which sounds like it was designed for a modded tpi, 112 lsa, 224/230 duration and 500/510 lift (@1.5) or 530/540 @ 1.6, obv a bit dearer than a flat tappet but sounds like the ideal cam so far ?
you and gregg have raised the issue of the 3200 converter, but the purchase, install and trans service etc owes me $1200, so its staying in there, right or wrong, but one thing is for sure, it does go a lot harder than the stock one did !

 

hi nick, yes i have an ed wright fastchip in my 85 too, not perfect but it does go a lot harder than the stock one, needs a bit of a re burn but i think i will probably have to buy the gear and do some data logging first to help get things right !

 

Roller cam conversion would be nice and the 224/230 comp will work nicely and work with the 3200 stall. Tpi's restriction will be based on how much porting is done and how far siamesed it is. More port work and more siamesing, more rpm you can pulll and compliment the cam and thus more power to be made