30/30 in an orherwise stock LT1
06-21-2018, 10:30 PM
#1
Drifting
Thread Starter
30/30 in an orherwise stock LT1
ok, who moved from the Lt1cam to the 30/30 or viseversa and what/ if anything did you discover in annotherwise stock LT1
im lining all my parts to build a 70 LT1 but debating on if I should run the earlier cam or not
m20/3.70/ps/pb/ac
im lining all my parts to build a 70 LT1 but debating on if I should run the earlier cam or not
m20/3.70/ps/pb/ac
With the better springs it will really wind up.
06-22-2018, 08:43 AM
#5
Drifting
Thread Starter
06-22-2018, 08:44 AM
#6
Drifting
Thread Starter
i plan to drive the car daily
06-22-2018, 11:30 AM
#7
Old Pro Solo Guy
I ran the 30-30 cam on my stock 70 LT1 for 28 years.
Soft under 3300 and then felt like 2 more cylinders kicked in.
What a rush. LT1 cam had a much milder to no kick at 3300.
With better springs it reved like a mad man to 7200 rpm, like a DZ 302. But with much better torque.
Power started to drop at 6600 vs about 7k for the DZ.
Got it to run on pump gas too. But had to give if lots of initial timing,(like 12-15) and limit total timing to 28-30 degrees.
900 rpm was as low as I could get it to idle and still work the power steering.
Ran stronger with some race gas (5 gal) when I could bump the timing back up to 36 total. But I rarely did that.
Rare was the BB I couldn't keep up with on the street.
(Just don't pick on a Hi Perf BB.)
13.7 at 106 in a 70-1/2 Z28.
Estimated a 425 HP with headers and flowmasters.
Soft under 3300 and then felt like 2 more cylinders kicked in.
What a rush. LT1 cam had a much milder to no kick at 3300.
With better springs it reved like a mad man to 7200 rpm, like a DZ 302. But with much better torque.
Power started to drop at 6600 vs about 7k for the DZ.
Got it to run on pump gas too. But had to give if lots of initial timing,(like 12-15) and limit total timing to 28-30 degrees.
900 rpm was as low as I could get it to idle and still work the power steering.
Ran stronger with some race gas (5 gal) when I could bump the timing back up to 36 total. But I rarely did that.
Rare was the BB I couldn't keep up with on the street.
(Just don't pick on a Hi Perf BB.)
13.7 at 106 in a 70-1/2 Z28.
Estimated a 425 HP with headers and flowmasters.
Last edited by leigh1322; 06-22-2018 at 11:43 AM.
06-22-2018, 11:47 AM
#8
Le Mans Master
Here are the open/close points for both cams. Very close in these numbers. Remember these are gross tappet lift and all the clearance ramps and lash are gone by .050" tappet lift.
LT-1 @ .050” Tappet Lift
IO @ 11 BTDC
EO @ 69 BBDC
IC @ 51 ABDC
EC @ 5 ATCD
Crane F-278-2 @ .050” Tappet Lift
IO @ 10 BTDC
EO @ 63 BBDC
IC @ 48 ABDC
EC @ 5 ATDC
I used the DCR calculator on the Crane and it works. The LT-1 and the Crane actual lashed and running valve events are just within a few degrees of each other. Using Dukes cam lobe maps to verify. There are others here that have experience with stock iron heads and this cam. Maybe some of them will jump in here.
If the Crane lifts higher and faster after .050" tappet lift, the cam is effectively BIGGER than the LT-1 and should like the compression even more.
Last edited by stingr69; 06-27-2018 at 07:58 AM.
06-22-2018, 12:04 PM
#9
Team Owner
The 30-30 and LT1 cam are just such old technology that they're really junk I rebuilt my friends LT1 using the crane mechanical 238 / 248th and it ran much better
The following users liked this post:
stingr69 (06-22-2018)
06-22-2018, 02:40 PM
#10
Le Mans Master
Crane F-278-2, 238/248 @ .050, .480"/.500" - Good low end and mid range torque and HP, fair idle, moderate performance usage, bracket racing, good w/ plate or manifold nitrous system, 3400- 3800 cruise RPM, 10.0 to 11.5 compression ratio advised. .022"/.022" lash.
3000-6800 RPM, Float at 7400 RPM.
Whats not to like?
3000-6800 RPM, Float at 7400 RPM.
Whats not to like?
06-22-2018, 04:03 PM
#11
Drifting
Thread Starter
Would love to hear from someone who ran the Crane F278-2 in a 11:1 350 without detonation issues on Pump Premium
i know from experience fhar the LT1 and 30/30 can do it from experience
i also had a 11:1 350 with the old Comp 292 and seem to recall that working just fine and ran great but i dont want a hud orherwise Id run that cam
Also, you guys running non-OE frinds. Are you all running manifolds or headers?
the tighter lsa does not like cast iron manifolds
i know from experience fhar the LT1 and 30/30 can do it from experience
i also had a 11:1 350 with the old Comp 292 and seem to recall that working just fine and ran great but i dont want a hud orherwise Id run that cam
Also, you guys running non-OE frinds. Are you all running manifolds or headers?
the tighter lsa does not like cast iron manifolds
06-22-2018, 05:51 PM
#12
Team Owner
Yes, I installed this cam in two different motors. although I used 1.6 roller rockers because the heads had screw in studs. both motors originally had 186 casting 64 cc 2.02/1.60 manley race flow stainless valves. flat milled, port and polish. both had the lt1 aluminum intakes. Later on my buddy wanted more bang so it got 195 cc aluminum heads with 64 cc chambers.
https://www.summitracing.com/parts/crn-113841/overview/
https://www.summitracing.com/parts/crn-113841/overview/
06-22-2018, 06:06 PM
#13
Melting Slicks
The LT1 engine has an advertised 11 to 1 compression ratio. Like most all Chevy engines from back then, they don't actually have the advertised compression ratio. The chambers tend to be over 64cc and the pistons are down in the hole quite a ways. They can be 1 whole point low and usually are. If it was a true 11 to 1 running iron heads with their inefficient chambers and lack of a tight quench, you probably couldn't get by on pump gas at all.
Mike
Mike
06-22-2018, 07:28 PM
#14
Drifting
Thread Starter
The LT1 engine has an advertised 11 to 1 compression ratio. Like most all Chevy engines from back then, they don't actually have the advertised compression ratio. The chambers tend to be over 64cc and the pistons are down in the hole quite a ways. They can be 1 whole point low and usually are. If it was a true 11 to 1 running iron heads with their inefficient chambers and lack of a tight quench, you probably couldn't get by on pump gas at all.
Mike
Mike
Block has been decked and pistons are an honest .015 in the hole.
06-22-2018, 08:13 PM
#15
Team Owner
06-26-2018, 08:18 PM
#16
Melting Slicks
Between the 30-30 and the LT1, it depends on what you like and the usage. For the rush above 3500 rpm I like the 30-30; for general driving, the LT1 gets the nod. After reading Duke's article about Tale of Two Camshafts, I am tempted to try the LT1 again, but with 1.6 intake rockers to make up for the smaller intake lobe.