1985 carbed corvette
I origionally had and ran a 355 9.8-1 Canfield 195's ( out of the box) performer RPM, Comp cams nitrous HP cam ( spec's below) 750 VS 08???elec choke,hooker super comps 2.5" dual ex. dynomax mufflers, turbo 350 2800 stall 3.07 stock D-36 26" tall slick and ET street. Car weight with driver is 3130. 51% on the rear.


According to the ET and MPH #'s from last year it looks like motor HP is 350-360. that seems low to me ? Max RPM is 6K

12.63@109 motor
11.38@ 118 100 shot
10.98@124 150 shot.

I have switched to a vic jr as i plan to spray 250 next year on a dual stage, ( NOS says no more than 150 on the dual plane)

anyway. My current cam specs are
262-280 adv ( 48 deg overlap)
218-230 @ .050
113 LSA 108 ICL
462-480.
I bought this because the RPM range was supposed to be 1600 to 5900. Then I talked to Robin @ comp and they dynoed it and came up with 350@ 5700 motor and 454@ 5850, 150 shot. The cam they recommend to make power to 6K is 230-244 @ .050 ( seems big to me) but it made 390 @ 5900 motor and 500@ 6100 150 shot.

I called cam motion and they speced out

272-284 ( 54deg overlap)
224-231 @ .050
112 LSA 106 ICL
496-512. they say 20-25 HP increase ??

Do you guys think this cam change is worth the money and time ?

thanks
Mike

If you're going to switch to the Vic Jr intake then a cam swap is definately worth it as you'll want to move the powerband up to work with it optimally anyway. When you say 6k is max RPM is that by choice or are you getting valve float?

Did cam motion spec you that cam with the Vic Jr or RPM? I definately think no matter what you decide some gears will help(if you arn't already thinking about it). More so if you go with the Vic Jr and larger cam combo.

What were your tq numbers like on the dyno? Those #'s don't seem all too far off for the cam you're currently running.

6K is max RPM by my choice.

cam motion speced this cam with the vic jr in mind. I will eventually go with a 355 rear gear.

My TQ #'s were exactly what comp got on their dyno . motor 400 and 150 shot 600.

I'm thinking of trying to get 50 more motor HP and limiting the spray to 200.

The larger comp cam seems really big to me with 230-244 @ .050. they say it pulls 13.5" vac at idle. Anyone drive a 355 around almost everyday with a cam that size ?

Mike

Well, my guess is as good as theirs...I guess. I also woulda figured about maybe 30 horses at most, but probably more like 20. As far as Et goes, Id also figure youd be solid 12.50 on motor, possibly touching the 12.40's with the new cam. So there should be roughly .2 tenths of a gain on your et with the swap to the slightly larger camshaft. Maybe more, but it might take a gear and converter change to to make it really pop much more than that.

Here is the kicker. The cam you currently have is a nitrous horsepower cam right? Is that new one also bred for the juice? In my opinion, going from 12.63 all the way to 10.90's on just a 150 shot is pretty darned impressive, so theres gotta be something good going on with your combo as is(my guess is the cam designed for the juice is whats really doing it). That new cam may or may not take to the juice as well, I cant say for sure. Although it probably will wake the motor up, you might not see as substantial of a gain on the juice if its not a dedicated nitrous camshaft. Know what I mean. Its a tough call, cause there is a little bit to be desired on your all motor ET and MPH, but man, the times on the bottle are impressive though as far as how much gain you get with such a small shot. Like I said, its a tough one cause I cant predict for sure if, and how much that cam will actually be worth both on and off the bottle.

Are you running through the exhaust at the track, or uncapped? Considering the nitrous, if you are going through mufflers it might be better worth it to step up the 2.5 inch piping to 3 inch. Run it uncapped first just to see if its worth it, cause if you show hardly no gain from pipes to no pipes, than the gains with a larger diameter tube will probably be minimal as well(read not worth it). And if you decide to swap cams, I probably talk to comp again and spec out another nitrous horsepower cam just because of the good results Id say you are getting with the current one. The new cam they specd out(the 230/244) is probably a wringer with a 250 shot. Hopefully some others will have some more insight on the matter.

Greg,

I'm running with mufflers so far. I'll uncap it next time and see the changes