396SBC Package...Opinions Please
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
396SBC Package...Opinions Please
I am very close to replacing the 383 in my Vette with a 396. My car is 80/20street/strip, see signature for performance. My primary concern is I plan on reusing my IRON WP SportsmanII heads and the motor will have a 9.9 - 10.2CR depending on deck hgt and head gasket. Here are a few cams I'm considering. They are all HR's. Which do you think will keep me out of detonation on 93 octane?
COMP XE282 230/236 @ .050 110LS/106IC 7.83 or 8.06 dynamic CR
VOODOO282 231/239 @ .050 110LS/106IC 7.83 or 8.06 dynamic CR
CROWER286 232/240 @ .050 110LS/106IC 7.7 or 7.93 dynamic CR
CROWER286 226/236 @ .050 114LS/110IC 7.44 or 7.67 dynamic CR
CROWER284 230/236 @ .050 110LS/106IC 7.77 or 7.99 dynamic CR
ISKY282/294 234/246 @ .050 110LS/110IC 7.58 or 7.59 dynamic CR
I have a very good cooling system. The car rarely exceeds 180 even in the heat of Summer. It also has full time fresh air induction. Both of which should help. Thanks for you input.
COMP XE282 230/236 @ .050 110LS/106IC 7.83 or 8.06 dynamic CR
VOODOO282 231/239 @ .050 110LS/106IC 7.83 or 8.06 dynamic CR
CROWER286 232/240 @ .050 110LS/106IC 7.7 or 7.93 dynamic CR
CROWER286 226/236 @ .050 114LS/110IC 7.44 or 7.67 dynamic CR
CROWER284 230/236 @ .050 110LS/106IC 7.77 or 7.99 dynamic CR
ISKY282/294 234/246 @ .050 110LS/110IC 7.58 or 7.59 dynamic CR
I have a very good cooling system. The car rarely exceeds 180 even in the heat of Summer. It also has full time fresh air induction. Both of which should help. Thanks for you input.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
My original 383 11.2 C/R with thermal coated pistons.... aluminum heads and a 232/240 112 S/R was always on the verge of detonation with super unleaded. I also felt that 232/240 was on the mild side even with Dart Pro 1 215cc heads. So I moved up on duration.
396 is considerably bigger. I have built 3 versions. The mildest uses a 236/242 or 244 duration roller. I would look for 236 - 240 intake duration and really be detonation free.
396 is considerably bigger. I have built 3 versions. The mildest uses a 236/242 or 244 duration roller. I would look for 236 - 240 intake duration and really be detonation free.
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
I haven't gone to a roller cam yet,but at 396 cubes,the more duration the less likely you'll detonate. I run 254@.050 with a 10.1:1 406 (AFR 195 heads) and run 36 degrees timing (mechanical) with 16 more vacuum,and get absolutely no pinging with 92 octane pump gas.My only complaint with my current combo is the idle. I run a Vic Jr,and tweaked Holley 3310 that I haven't been able to get to idle below 1000 rpms without stalling. Runs like King Kong to 7000 rpms though. I'm sure if I got a more modern 4 corner idle carb, that would not be a problem.
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
At what point (cam wise) in a Vette does vacuum become an issue with the brakes and headlights? That's another of my concerns. I have an 11:1 383 with a 242/248 @ .050 HR in another vehicle in which I have the idle set at 950. I have no issues with pinging but it also has aluminum heads. It pulls 10.5" vacuum in park/nuetral. Is there a threshold for vacuum to operate pwr brakes/headlights?
Last edited by nastee383; Aug 7, 2007 at 09:27 PM.
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
My original 383 11.2 C/R with thermal coated pistons.... aluminum heads and a 232/240 112 S/R was always on the verge of detonation with super unleaded. I also felt that 232/240 was on the mild side even with Dart Pro 1 215cc heads. So I moved up on duration.
396 is considerably bigger. I have built 3 versions. The mildest uses a 236/242 or 244 duration roller. I would look for 236 - 240 intake duration and really be detonation free.
396 is considerably bigger. I have built 3 versions. The mildest uses a 236/242 or 244 duration roller. I would look for 236 - 240 intake duration and really be detonation free.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
I recall some where below 12" Hg vacuum the accesories have problems. This at idle of course and intake vacuum will only decrease as engine speed increases.
I found a chart in one of D. Vizards book that was right on when cam duration on a forum members car was compared to comprssion ratio.
Sorry can't remmeber where that chart is now.
cardo0
I found a chart in one of D. Vizards book that was right on when cam duration on a forum members car was compared to comprssion ratio.
Sorry can't remmeber where that chart is now.
cardo0
Melting Slicks
Joined: Jul 2005
Posts: 2,060
Likes: 46
From: winter haven florida
St. Jude Donor '12
CROWER286 232/240 @ .050 110LS/106IC 7.7 or 7.93 dynamic CR
this is the cam just below what i went with in my 396 sb. with afr 195's and 10.5 to 1 comp. you can have the lsa custom ground at 12 or even 14 if you want. i went with the 236/242 cam. go hydroboost for the brakes and swap to electric motors for the lights.
this is the cam just below what i went with in my 396 sb. with afr 195's and 10.5 to 1 comp. you can have the lsa custom ground at 12 or even 14 if you want. i went with the 236/242 cam. go hydroboost for the brakes and swap to electric motors for the lights.
Last edited by 2000FRCZ19; Aug 8, 2007 at 12:56 AM.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
At what point (cam wise) in a Vette does vacuum become an issue with the brakes and headlights? That's another of my concerns. I have an 11:1 383 with a 242/248 @ .050 HR in another vehicle in which I have the idle set at 950. I have no issues with pinging but it also has aluminum heads. It pulls 10.5" vacuum in park/nuetral. Is there a threshold for vacuum to operate pwr brakes/headlights?
Having a high initial spark advance and dialing in the idle mixture A/F ratio can change the vacuum a couple of points higher.
I have 10 ish right now on my 434. The brakes are still fine, but the head lights are super slow. I just do a down shift with my foot off the gas petal to pop them up
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Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
CROWER286 232/240 @ .050 110LS/106IC 7.7 or 7.93 dynamic CR
this is the cam just below what i went with in my 396 sb. with afr 195's and 10.5 to 1 comp. you can have the lsa custom ground at 12 or even 14 if you want. i went with the 236/242 cam. go hydroboost for the brakes and swap to electric motors for the lights.
this is the cam just below what i went with in my 396 sb. with afr 195's and 10.5 to 1 comp. you can have the lsa custom ground at 12 or even 14 if you want. i went with the 236/242 cam. go hydroboost for the brakes and swap to electric motors for the lights.
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
I thought that the 242/248 cam would be hard to live with on the street also, but it has proven otherwise. My truck is every bit as streetable as my Vette. I guess sometimes you just get lucky.
Melting Slicks
Joined: Jul 2005
Posts: 2,060
Likes: 46
From: winter haven florida
St. Jude Donor '12
CROWER286 232/240 @ .050 110LS/106IC 7.7 or 7.93 dynamic CR
with the heads you have try to keep a tight quench to help out with the detonation. since this is more of a street car than a racer and you are wanting to do as little modding as possible i would choose this cam on a 112 lsa. should be plenty cam for the street. you could get more power using a bigger one but it will come at more of a cost than what you are looking for.
with the heads you have try to keep a tight quench to help out with the detonation. since this is more of a street car than a racer and you are wanting to do as little modding as possible i would choose this cam on a 112 lsa. should be plenty cam for the street. you could get more power using a bigger one but it will come at more of a cost than what you are looking for.