Right cam for 383 lt1 race truck
12-28-2011, 01:02 AM
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Right cam for 383 lt1 race truck Hi guys I'm new to the forum,I'm building a 383 lt1 4 speed manual race s10 and need some advice on a camshaft for this build,sorry to beat a dead horse but I want some well educated advice on this,let me break down the engine and parts as I have for it, lt1 block prepped for 383 ARP main studs/oil pump stud,eagle forged crank neutral balance,scat 6 " forged rods/ARP bolts,Ross forged pistons(pistons and milled heads=10.8 to 1),mahle file fit rings,King rod and main bearings,new lt1 643 heads p&p to stage 2,200 intake runners,Manley stainless 2.00,1.55 valves,ARP 7/16 screwed in studs/guide plates,comp 987 springs,comp retainers/locks,comp push rods/1.6 rr,lt1 intake heavily ported intake runners and t body ports are 58mm,58mm t body and 30 lbs hr injectors,will be lsx 411ecm and 8 coils,rear gear will be 4.56 8.8",trans will be a 4 speed muncie verti gate shifted this truck will be a street/strip but mostly strip,what cam will work best with the list of ingredients I have(I was thinking of xfi 280 or gm847 but unsure),thanks in advance for any and all input,with all that said anyone have a good used cam that would work for me,Greg
Last edited by 94ls10; 12-28-2011 at 01:09 AM.
12-28-2011, 07:37 AM
#2
With the limited head porting information you've posted, all recommendations you get on here are going to be pretty wild guesses, and being new on here you probably have no idea who's giving you the educated guesses and who has no clue.
I can tell you this much: neither of those cams you mentioned are what I'd put in a race motor. Gen I and II SBC heads generally perform better with a tighter lobe separation to help the intake flow with exhaust scavenging during the overlap period. And since it's a race motor, you don't need to be concerned with a good low-rpm idle, emissions, or mileage which is about all the wider LSA is good for with Gen I and II heads.
Also with that relatively low 10.8 CR, you have to stay conservative on intake duration to keep some midrange in the motor to get it off the line. 230 intake dur isn't too much, but unless you get some more compression in the motor, you'll want quite a bit of advance in the cam, something around 104 ICL.
Do you have flow data on the heads at the various valve lifts?
Somebody like Phil at Advanced Induction or Lloyd at Elliot Portworks, even if they didn't do the heads and intake, would probably be able to make a better guess on cam selection than anybody on here. And they both can supply custom grinds for whatever they come up with.
I can tell you this much: neither of those cams you mentioned are what I'd put in a race motor. Gen I and II SBC heads generally perform better with a tighter lobe separation to help the intake flow with exhaust scavenging during the overlap period. And since it's a race motor, you don't need to be concerned with a good low-rpm idle, emissions, or mileage which is about all the wider LSA is good for with Gen I and II heads.
Also with that relatively low 10.8 CR, you have to stay conservative on intake duration to keep some midrange in the motor to get it off the line. 230 intake dur isn't too much, but unless you get some more compression in the motor, you'll want quite a bit of advance in the cam, something around 104 ICL.
Do you have flow data on the heads at the various valve lifts?
Somebody like Phil at Advanced Induction or Lloyd at Elliot Portworks, even if they didn't do the heads and intake, would probably be able to make a better guess on cam selection than anybody on here. And they both can supply custom grinds for whatever they come up with.
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12-31-2011, 08:25 PM
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I have changed pistons from -12 to -5 so compression now should be around 11.7 or more,what would you suggest for cam and springs wicked94z thanks,Greg.
01-01-2012, 02:03 AM
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Yea compression will be up in the 12+ range with a -5cc piston depending on chamber CC. The PAC 1220s will work very well here, Lunati sells them as 74820LUN and they're 140 from race-mart. Great spring! You can run a .610" lift cam to 7200+ with them and they will last. What kind of RPM do you want to turn? You don't need a baby cam to make great torque in the midrange
01-02-2012, 10:07 PM
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I just put that 280 XFI in my new 355, with 11.4 compression and it kicked the hell out my old custom grind. The car has torque everywhere and runs 2000 to 6500 all day long. I think it would be perfect for your truck...
01-02-2012, 11:02 PM
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What works in a street 355 fbody won't be the same as a race 383 truck.
01-06-2012, 10:19 PM
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