Small Block & Big Block Chevy Specific - Thinking of a hotter cam for my vortec 350
07-12-2011, 12:04 AM
I have a Monte Carlo SS with a 9" 3.70's, 700R4, Vig 2800, and a L31 350 vortec, Performer RPM Air Gap, 600cfm carb, 1.75 LT's 2.5 duals and a stock LT4 cam. I bought it from my best friend, we built the motor a couple years ago. It had a Pro Charger on it, but it sold the blower and just been DD'ing the car for a while. Now, he offered me the car for a price I cannot turn down.
I am thinking changing cams, and considering going with either the comp XR270HR, Crane 227, LT4 Hot Cam, or the Crower 00409.
I would like a slightly choppy idle, but want it to run like a scalded dog too! I know the Crane 227 held the LT1 Cam Only record for a good while. I wonder how it would run on a 9.3:1 CR motor instead of a 10:1 like the LT1?
07-12-2011, 01:06 PM
One of the first things to consider when picking the cam is have the valve guides been machined down to accept higher lift? Stock I think they are good up to .480 or something like that. If they haven't been cut down that will limit your cam selection some.
What are the spec's on the cams you have and are looking at?
The lower compression ratio will play a part in it too.
07-12-2011, 05:01 PM
Comp XR270HR is a nice cam and i would recommend having the heads shaved to get a little more compression !
07-12-2011, 10:07 PM
Thank you for the replies! I come from a LSX back ground. built a couple of them. but the GenI/II stuff is new to me. The guides will be cut, and beehives installed. How far can I shave the heads before I run into PTV issues? I would like to bring it from 9.3 to 10:1 if I can.
Oh, and to answer the second reply about the specs...
the Crower is-
Intake Duration at 050 inch Lift 212
Exhaust Duration at 050 inch Lift 218
Duration at 050 inch Lift 212 int./218 exh.
Advertised Intake Duration 284
Advertised Exhaust Duration 288
Advertised Duration 284 int./288 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.462 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.470 in. w/ 1.5RR
The Comp XR270HR-
Intake Duration at 050 inch Lift 218
Exhaust Duration at 050 inch Lift 224
Duration at 050 inch Lift 218 int./224 exh.
Advertised Intake Duration 270
Advertised Exhaust Duration 276
Advertised Duration 270 int./276 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.495 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.502 in. w/ 1.5RR
The Crane 227 and the Hot Cam are in the LT1 cam selection guide here
07-12-2011, 10:52 PM
How far can I shave the heads before I run into PTV issues?
That will depend on if your pistons have valve reliefs or not. Also what your deck height is and how low your pistons sit in the block and your head gasket thickness.
Sorry to be so ambiguous about it but there are several factors.
07-13-2011, 12:23 AM
No problem... I am trying to remember what pistons we put in it. I believe they were new stock L31 pistons, with a stock deck 350 block. no over bore.
07-13-2011, 01:21 AM
Update, the pistons are 13cc and around 30 in the hole.
07-13-2011, 08:51 PM
http://www.summitracing.com/parts/CCA-12-214-4/ I run this cam on my vortecs and did not have to cut the valve guides plenty of room with beehives and new retainers just put a socket on valve seal and bump it down. Runs really good just a .040 over with flat tops
07-17-2011, 01:38 AM
After speaking with Loyd, his 218/224 .544 .544 111 should work well. according to Loyd and Desktop Dyno 2003, that cam should make more power under curve and more trq at peak as well compared to the Hot Cam. The Hot Cam beat it at peak by 2hp.
Showing peak trq at 4000 and peak hp at 5500.
bump my stall up to a 3600 vig (should flash close to 4K) would make for a fun low 13 high 12 car.
might hit it with a 150 later :D
07-17-2011, 01:55 AM
Do you think that an engine that peaks at 5500 needs a 3600-4k stall?
I don't know that's why I'm asking.
07-17-2011, 09:43 PM
I was looking at peak trq... but you're right. a 3200 might be good as its only making 10 less trq... it carries the hp to almost 6000.
07-18-2011, 03:26 PM
Played with Desktop Dyno 2003 more, and it really liked changing LE's cam from a 111LSA to a 110LSA and leaving the events the same, Also liked 10:1 CR from the stock 9.4:1 :nod: