383 Too Much Cam?? Need Help!
Thread Starter
Racer
Joined: Jan 2006
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From: Orange massachusettes
383 Too Much Cam?? Need Help!
Looking at 383, vortec heads w/2.02-1.60 valves, 9.5 compression, cast crank, Hyper pistons has hyd flt cam of .487 IN. lift 234 degree @50/.508 EX lift 244 degree @50. The lift looks fine to me but what about the duration?? I'm looking for strong street engine but would like it to idle and be responsive/at lower rpms. What do you guys think?? I'm about ready to purchase a crate engine and this is my only concern. By the way this is the Blueprint 383 engine.
Safety Car
Joined: Aug 2000
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From: San Antonio TX
Assuming that this is a four speed that originally came with the LT-1, it wouldn't be too bad. LSA is an important component. A wide lsa and it's going to be soft on the bottom end. A close lsa and it's going to have a very choppy idle. Would also depend on the gear ratio. A 3.36 with a close ratio and you better have a good clutch in the thing. If it were me, I'd drop the duration about 10 degrees on each side and match the lsa to what I really wanted from the thing. Don't get too wrapped up on the lift. The heads go soft over .450 anyway.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
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From: Austin TX
Might be too big. What tranny and rear gears? Power brakes? Don't forget, on the street you spend 95% of your time below 3500 RPM. Also, I'm no fan of dual pattern cams, especially if you have decent heads and good exhaust,..so tell us more about your rig.
Last edited by 73, Dark Blue 454; Aug 31, 2006 at 11:29 PM.
Team Owner
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Originally Posted by 72 LT1
Looking at 383, vortec heads w/2.02-1.60 valves, 9.5 compression, cast crank, Hyper pistons has hyd flt cam of .487 IN. lift 234 degree @50/.508 EX lift 244 degree @50. The lift looks fine to me but what about the duration?? I'm looking for strong street engine but would like it to idle and be responsive/at lower rpms. What do you guys think?? I'm about ready to purchase a crate engine and this is my only concern. By the way this is the Blueprint 383 engine.
383's are a TQ moster compared to 355ci. With 9.5 it must have some kind of dished pistons. It would run very well with some kind of flat tops with -6cc because of the valve reliefs. My present 383 is 11.2 with a roller cam and runs fine with our Califorinia mandated 91 octane with only a little more of a cam and 32 degrees of total timing.
Le Mans Master
Joined: Dec 2003
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From: Fremont CA
Originally Posted by gkull
The only real problem with that cam is lack of compression with only 9.5.
383's are a TQ moster compared to 355ci. With 9.5 it must have some kind of dished pistons. It would run very well with some kind of flat tops with -6cc because of the valve reliefs. My present 383 is 11.2 with a roller cam and runs fine with our Califorinia mandated 91 octane with only a little more of a cam and 32 degrees of total timing.
383's are a TQ moster compared to 355ci. With 9.5 it must have some kind of dished pistons. It would run very well with some kind of flat tops with -6cc because of the valve reliefs. My present 383 is 11.2 with a roller cam and runs fine with our Califorinia mandated 91 octane with only a little more of a cam and 32 degrees of total timing.
Last edited by Solid LT1; Sep 1, 2006 at 04:06 AM.
Thread Starter
Racer
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From: Orange massachusettes
Thanks for all the feedback. I have 3.55 gears w/M21 4spd. The camlisted has LSA 112. Will use headers and full exhaust. This is the crate engine available thru JEGS performance/Blueprint series engine. Tech at Blueprint told me this set up has better idle and stronger lower end power, than GMs ZZ383, but that has roller cam, so not sure how to make direct comparison as to what the duration OR LSA should be. BTW I dont have power brakes.
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
I really think with the gears you have and manual brakes that cam will be fine. They bumped up the LSA to reduce overlap and that will allow a bit more duration. Also a 383 has more bottom end and requires a little more duration than a 350. I like it If the springs will handle it 1.6 rockers
Last edited by 63mako; Sep 1, 2006 at 07:48 AM.
Le Mans Master
Joined: Oct 2001
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From: Wildwood IL
If you like hight lift at lower durations, DEFINITLY look into Crower Hight Lift 350 Series Hydraulic Rollers. Expensive, but top of the line quality.
http://crower.com
Eddie
http://crower.com
Eddie
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Le Mans Master
Joined: Oct 2004
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From: Orlando Florida
St. Jude Donor '05
This is the Edelbrock RPM cam ? 234/244 dur @50 sounds like it...... I wasn't happy at all with that cam (350 with 9:1CR) - compression was way too low, you need about 10:1CR with that cam.
A 383 might require less CR than a 350 but still.... I'd choose a little milder cam (220/230dur@.050)
A 383 might require less CR than a 350 but still.... I'd choose a little milder cam (220/230dur@.050)
Le Mans Master
Joined: Oct 2004
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From: Orlando Florida
St. Jude Donor '05
Originally Posted by 72 LT1
Redbad1979, was that cam week on the bottom end?? Did it idle below 900 rpm??
Yes, even with fresh plugs it was weak below 3500 rpm..... at idle it sounded like a race car but that's the only positive thing I can tell you about this cam....my CR was stock L48 (8.7:1) increased to 9.3:1 or so with 64cc chamber heads.... not enough....
Racer
Joined: Jun 2004
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From: Okiehoma
Originally Posted by 72 LT1
Looking at 383, vortec heads w/2.02-1.60 valves, 9.5 compression, cast crank, Hyper pistons has hyd flt cam of .487 IN. lift 234 degree @50/.508 EX lift 244 degree @50. The lift looks fine to me but what about the duration?? I'm looking for strong street engine but would like it to idle and be responsive/at lower rpms. What do you guys think?? I'm about ready to purchase a crate engine and this is my only concern. By the way this is the Blueprint 383 engine.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
That cam would be nothing below 2000 RPM. With the close ratio Muncie, 3:55's, and 9.5 compression, it would be absolute mush on the street.
I'd recommend Comp's Magnum 270H,..single pattern (you're running headers,..don't need dual pattern). It has 224 @ .50 and .470" lift with 1.5's. In a 383, she'd pull all the way up to 5500 RPM and there would be plenty down at 1500 so you don't have to ride the clutch keep the engine running as pull away from stop sign
My opinion.
Wes
I'd recommend Comp's Magnum 270H,..single pattern (you're running headers,..don't need dual pattern). It has 224 @ .50 and .470" lift with 1.5's. In a 383, she'd pull all the way up to 5500 RPM and there would be plenty down at 1500 so you don't have to ride the clutch keep the engine running as pull away from stop sign
My opinion.
Wes
Thread Starter
Racer
Joined: Jan 2006
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From: Orange massachusettes
Called Blueprint Engines, was ready to order 383, but I wanted them to build one w/milder(less duration)cam. Was told that they wouldnt do it. Best they could do was sell me the shortblock w/out cam. Of course now there is no warranty. The 2yr 24k mile warranty on the engine was a BIG selling point for me. At $3100 the complete engine seemed like a great value, BUT $1700 for cast botom end short block minus cam doesnt sound so great.
Race Director
Joined: Mar 2001
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From: Living in the Hartland
Originally Posted by 72 LT1
Thanks for all the feedback. I have 3.55 gears w/M21 4spd. The camlisted has LSA 112. Will use headers and full exhaust. This is the crate engine available thru JEGS performance/Blueprint series engine. Tech at Blueprint told me this set up has better idle and stronger lower end power, than GMs ZZ383, but that has roller cam, so not sure how to make direct comparison as to what the duration OR LSA should be. BTW I dont have power brakes.
Do not see anyway that the eng you desc has better low end than a ZZ383, the ZZ has more compression (9.8 vs 9.5), longer stroke (3.80 vs 3.75) and a shorter duration/higher lift roller cam
Race Director
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From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by Fevre
DANGER WILL ROBINSON!
Do not see anyway that the eng you desc has better low end than a ZZ383, the ZZ has more compression (9.8 vs 9.5), longer stroke (3.80 vs 3.75) and a shorter duration/higher lift roller cam
Do not see anyway that the eng you desc has better low end than a ZZ383, the ZZ has more compression (9.8 vs 9.5), longer stroke (3.80 vs 3.75) and a shorter duration/higher lift roller cam
Roller cam in a 383 = 20 to 30 HP. with same lift and duration. Search ryanscarpage. Lots of good information and comparisons on combo's with cam specs on each.
Will help with your decision.
Last edited by 63mako; Sep 3, 2006 at 11:50 AM.
Le Mans Master
Joined: Apr 2006
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Originally Posted by 63mako
Roller cam in a 383 = 20 to 30 HP. with same lift and duration. Search ryanscarpage. Lots of good information and comparisons on combo's with cam specs on each. Will help with your decision. If you can afford the $5100 ZZ383 you get a lot with it, fastburn aluminum heads, hydraliuc roller, 4340 chrome moley steel crank, brand new block, new rods,new everything.
Last edited by Little Mouse; Sep 3, 2006 at 02:50 PM.