Im putting a 383 stroker in with my ATI supercharger. I emailed comp cams about getting a custom cam for my car. He said I dont need a custom cam, he told me they have a cam that would work good for my set up. This is what he emailed me.

PART NO. 07-468-8
01 INTAKE MASTER 3018
02 EXHAUST MASTER 3039
03 ENGINE LT1 292XFI HR-13
04 GRIND NUMBER LT1 292XFI

INT EXH
05 HYDRAULIC Y/N YES 14 DUR @.050
242 248
INTAKE EXHAUST 15 LOBE LIFT .3650
.3620
06 VALVE ADJUSTMENT HYD HYD 16 ROCKER RATIO
1.60 1.60
07 MAX GROSS VALVE LIFT .584 .579
08 DUR @ .006 TAPPET LIFT 292 300 17 LOBE SEPARATI 113.0
18 ADVANCE 4
09 VALVE TIMING OPEN CLOSE 19 VALVE SPRINGS 26918
@ .006 10 INT 37 75
11 EXH 87 33 DATE SETUP 10/18/2004
12 THESE SPECS ARE FOR CAM(S) INSTALLED
@ 109.0 INTAKE CENTERLINE

I told him what springs I had (LT4) , he said I might need heaver springs. He sent me a part # for springs. I looked them up and the #s for the comp cams seem smaller than the LT4, this is what they are

Outside Diameter of Outer Spring (in): 1.055
Coil Bind Height (in): 1.085
Damper Spring Included: No
Spring Rate (lbs/in): 313
Inside Diameter of Outer Spring (in): .885
Inside Diameter of Inner Spring (in): .885
Valve Spring Style: Beehive
Coated: No

This is the LT4
Outside Diameter of Outer Spring (in): 1.320
Coil Bind Height (in): 1.220
Damper Spring Included: No
Spring Rate (lbs/in): 332
Inside Diameter of Outer Spring (in): 0.802
Inside Diameter of Inner Spring (in): 0.802
Valve Spring Style: Standard
Coated: No

What springs would I need?
Also will it work with my other lt4 stuff and my stock heads? (I know I need bigger heads that will be this winter)

 

anyone??

 

If you like you can mak a search on the behive 918 springs, but this is a stout spring that can support high lifts (+ 0.600) and is very stable at high rpm inspite of it being single and having a lower pressure.
I'm running them with slightly higher lift then you.

 

I'm changing my springs from the LT4 to the LS1 beehives right now due to a cam change to the 224/236 XE grind. The lobes on the xe cams require a better spring. Comp cams has supposedly revved the 26918 beehive spring to an amazing 7500 rpm on an LS1 without failure. I know the valves are a little lighter on the LS1, which helps.

Your going to need to order the chromoly retainers, pt #787 along with the matching seats, pt #4705. The installed height has to be checked. The spring will be stiffer with a shorter installed height. You can order special 7 deg locks which can alter the installed height +- .050". You can also calculate how stiff the spring can be at different installed heights.

 

Hey EDS Z28 thanks for the info. I tried to look up the matching seats, pt #4705, I could not get them to come up. Do you have a different part#?

I dont know a lot about this valve train stuff so all help is apreceated. The retainers and the seat are the only other parts ill need right? You say I might need the special 7 deg lock. How do I know if I need the locks.Will a performance shop know whats going on with all this stuff if I tell them what you said. I suppose I have to set the height and spring presure to the cam that I get?
Do you know if that cam is good for my set up and will that cam work with my stock heads?? I have dished pistons for 9.1 com. so I dont think the valves would hit. Thanks for the help!!

 

i would go with somehting a little bigger that the 918, the ramps on that cam are very steep requiring a dual spring, and with that cam i would look at about 155 as a minimum


may i suggest the kmotion 800 springs they are 165 on the seat and 495 open and are good to .700 lift and are duoble springs and are only 89.95 at summit

 

Well, you have to use a height mic to measure the installed height first with standard 7 deg valve locks. It doesn't matter if the cam is in yet or not. The spec installed height for those springs is 1.80". If you get 1.74", using a valve lock with +.050 will give you 1.79", which is very close. If you come up short like 1.75", the spring will be stiffer and you will be closer to coil bind when the valve opens. You must check for coil bind when the valve is open and the spring compresses. The clearance between the coils must be 0.060" or greater. Another way to adjust the valve spring installed height is with longer valves and valve shims.

If that cam was recommended by Comp Cams, I would go with it. Ya, ported heads help, but it's a whole different ballgame with a blower bolted on.