duration

[chrisr0315]

hello .great forum
Im building sbc 383 TPI ( big intake/runners/plenum heavily ported w/ 58 mm throt body) for my 85 Vette/ manual 3.45 gears ( NO emissions required / ECU w/ chip) . Edlebrock Performer RPM Xtreme Aluminum heads( 185 cc int port ,70cc comb chamber , 2.02/1.60 . 5.7 rods clearanced for roller . Speed pro Hyper flat tops , single side relief, will give me about 10.3 comp . Headers . Want to go hydraulic roller set up . Three questions :
1) Am I limited to "Retro " style cams in the diff lines you offer or can I use any Thumper or Extreme oe XFI cam ?
2) What would be streetable duration for this
3) do I have to use a rod sizer to get pushrod length or will rods from retro kit work
Im looking 220 -236 int,230-246 exh. @ .050, .500- .540 int. lift / .520 - .560 exh. LSA 108-110 for lopy/rough idle
Thanks for helpping
Chris

[chrisr0315]

can you help in cam selection . can you give examples in your different lines ( ie. Thumper , XFI , Magnum , XE )

[amick]

Chris is your goal with the engine max power while still being streetable or are more worried about sound?

[chrisr0315]

as long asit sounds cool.....jus kidding . My goal is a higher power curve for my TPI .I know by design ,it will have low end torque ,I want to build on that and increase the power peak on both horsepower and torque .
I want a strong cam, but dont want to go sosteep on duration . I cant operate my acc's . will those 70 cc heads let a 383 take mid 230 on intake duration @ .050 and deal with occasional street traffic ? My goal is 450+ HP /TQ . Plus I want a cool sounding idle that tighter LSA will give me, with a stronger , higher peak @ mid/upper-range
Deffinitely Max Power with steetability
Thanks
Chris

[amick]

I would use a part number 12-000-8 (retro fit roller core) with a grind number CS 3016/3037HR110+4 (be sure your tuner can tune the computer with that tight of a seperation and this much duration, you may be better off getting the 112 LSA). This is a custom grind camshaft and will typically take 3-5 business days to complete. I have provided the specs for it below. With the 383 stroker engine you will probably need to request this on a 1.050 base circle to clear your rods.

Duration @ .050 230/236
Lift w/1.5 rockers .540/.536
LSA 110 dgrees (this can be changed as mentioned above)

[chrisr0315]

I was thinking about the 12 433 8 cam ,but as your recommendations shows, my thought was too high duration . the ca m you metion is similar to your cca 12 432 8 extreme cam , but as you state 112 LSA may be the way to go .
Thankyou for the info AMICK
CHris

[amick]

No problem at all Chris. You actually have enough engine to go with the larger cam you were thinking of but I find it doubtful that you will be able to get anyone to tune the TPI computer to work with that much duration. The TPI computer is fairly limited. If you can find a tuner that feels capable of going with more camshaft let me know and we can you a different grind number. Those lobes are also XFI lobes which are slightly more aggressive than the XE lobes but yes it is very similar to that part number.