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  #31 (permalink)  
Old 03-11-2013, 11:49 AM
How fast is fast enough?
 
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Quote:
Originally Posted by F-BIRD'88 View Post

EG: .480" x 1.0666 ='s .512" net valve lift

you need to pay attention to valvetrain geometry.
Forgot lash- .022"

NET valve lift with 1.6 rockers is .490" assuming a perfect 1.6 ratio and .022" lash (either of which will likely not be right on)

.490" lift is NOT asking much with today's springs and if properly set up would not lead to any appreciable loss in durability.

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  #32 (permalink)  
Old 03-11-2013, 01:52 PM
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Originally Posted by logan1 View Post
Ok from what i have read the 1.6 rockers will only give me 10hp more than the same cam with 1.5's. I also read a few posts that said that they wreak havoc on the valve train; not sure if this is substantiated info or not but at this point im not too inclined to run em.

Also i saw that thread posted by landshark and the problems he is having with 1.65.
My issues were operator error, not the 1.65 rockers. Took one day and the correct rods and plates and she purrs like a kitten. Until you pull her tail.

Here is an interesting read on using larger rockers. In fact many times the larger rockers are easier on the valve train. Don't be scared of 1.6 rockers. They not only increase lift but increase the "effective" duration at 0.050" since they lift the valve quicker. True duration is not changed.

Higher Ratio Rocker Arms
Quote:
Higher ratio rocker arms open the valve faster, higher, and hold it open for a much greater total period of time as compared to lower ratio units. Does this cause more stress on the valve train? There will be more pressure on the cam lobes due to the friction and pressure caused by the higher lift and resultant greater spring load. However, as compared to providing the same higher lift and effective longer duration with a more radical cam and even stiffer springs, the higher ratio rockers may create less total valve train stress. And such a cam lobe would be very aggressive and would require much heavier springs to keep the lifter from flying off the lobe. Very radical lobes will also add more side stress on the lifters/bores and could possibly cause lifter bore failure.
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  #33 (permalink)  
Old 03-11-2013, 01:59 PM
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Originally Posted by logan1 View Post
In the future I will probably go to EFI but for now holley is my girl.
I said the same thing for a season of AutoX, Road Racing and Drift. Then gave up and went Fuel Injection. Wish I had switched earlier. The only guys I see staying carb on those circuits are the "Nostalgia" classes which have to. Get her running on a carb and start saving for and piecing together a FI system.

Air gap will be a great intake for you. Stronger signal to the carb and higher vacuum for brakes. I used mine (ported) on my 434" SBC with great results. I only recently switched to a ported Hurricane.
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  #34 (permalink)  
Old 03-11-2013, 02:06 PM
How fast is fast enough?
 
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Quote:
Originally Posted by Landshark928 View Post
My issues were operator error, not the 1.65 rockers. Took one day and the correct rods and plates and she purrs like a kitten. Until you pull her tail.

Here is an interesting read on using larger rockers. In fact many times the larger rockers are easier on the valve train. Don't be scared of 1.6 rockers. They not only increase lift but increase the "effective" duration at 0.050" since they lift the valve quicker. True duration is not changed.

Higher Ratio Rocker Arms
Also, for a given lift the springs can be ran with a hair less pressure with more ratio as well as their is less push rod and lifter movement.
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  #35 (permalink)  
Old 03-11-2013, 02:15 PM
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The LS engines have 1.7 rockers for a reason.Smokey Yunick used 1.7 rockers on gen 1 engines in the early 70s.
THe problem with 1.7 ratio rockers is the rocker stud boss is cast and drilled to optimise 1.5:1 rockers.
If you are building a mild gen 1 then use the cam that meets your requirements. To know your requirements,YOU, decide how much power you want,get the heads that work,use the cam and parts that match,the fuel management and exhaust need to match also.

NOTE: 1.6 ratio rockers wont make much difference if you have the correct cam to begin with,,,
Landsharks engine makes a lot more HP so higher ratio rockers are needed.
side note,by the time I convert to F.I. like shark,he will have converted to rocker shafts like me,,,
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Old 03-11-2013, 03:05 PM
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Originally Posted by vinniekq2 View Post
The LS engines have 1.7 rockers for a reason.Smokey Yunick used 1.7 rockers on gen 1 engines in the early 70s.
THe problem with 1.7 ratio rockers is the rocker stud boss is cast and drilled to optimise 1.5:1 rockers.
If you are building a mild gen 1 then use the cam that meets your requirements. To know your requirements,YOU, decide how much power you want,get the heads that work,use the cam and parts that match,the fuel management and exhaust need to match also.

NOTE: 1.6 ratio rockers wont make much difference if you have the correct cam to begin with,,,
Landsharks engine makes a lot more HP so higher ratio rockers are needed.
side note,by the time I convert to F.I. like shark,he will have converted to rocker shafts like me,,,
I would love shaft rockers! But twin turbos are next for me this spring...
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Old 03-11-2013, 04:24 PM
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Well for me at this point i just want to get the car running and enjoy it. I personally think i would be very happy if my car had around 350HP; a number i think should be attainable with my current setup. Which would be a hell of a setup for me since the last time i drove the car it had the stock 2.4L straight 6 motor with no rebuilds since 1970 in it making around 120HP or so; a 4 spped transmission and 3.36 rear gears.

I going to go with the cam vinnie suggested and 1.5 rockers for now and see if i like it. If i feel i need more HP i can always modify later. And hopefully this coming winter ill be able to get an EFI system for the car.
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  #38 (permalink)  
Old 03-11-2013, 04:38 PM
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If it makes less than 350 HP after proper tuning,Ill buy you lunch,lol...
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Old 03-11-2013, 10:01 PM
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Quote:
Originally Posted by vinniekq2 View Post
If it makes less than 350 HP after proper tuning,Ill buy you lunch,lol...
That would the most expensive lunch i've ever had. Well im going to take ur confidence as a positive indication about my HP numbers.

1 more questions:

(1) Should i gasket match the intake and heads?
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Old 03-11-2013, 10:03 PM
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also Vinne and Landshark approx how much HP/TQ are your cars putting to the ground?
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  #41 (permalink)  
Old 03-11-2013, 10:04 PM
How fast is fast enough?
 
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Originally Posted by logan1 View Post
That would the most expensive lunch i've ever had. Well im going to take ur confidence as a positive indication about my HP numbers.

1 more questions:

(1) Should i gasket match the intake and heads?
Absolutely not! The gasket is irellavent, match the heads and the intake to each other not some damn gasket
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Old 03-11-2013, 11:08 PM
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dyno

Quote:
Originally Posted by logan1 View Post
also Vinne and Landshark approx how much HP/TQ are your cars putting to the ground?
My car is going on the chasis dyno after paint.I did the original tune on an engine dyno,I want to see how much is lost through my car.I will post a video when its on the dyno
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  #43 (permalink)  
Old 03-11-2013, 11:22 PM
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Originally Posted by logan1 View Post
also Vinne and Landshark approx how much HP/TQ are your cars putting to the ground?
572RWHP @ 6500rpms on a Dynojet NA. 744RWHP with a 200HP shot of N20 running rich. I shift at 7300rpms. Car is about 2800# with me. Will be a little more soon due to roll cage.

421SBC Dart block - Callies Dragon Slayer Crank, Callies H-Beams, Probe Forged Pistons
Airwolf 220 Heads 11:1 compression
Lunati Voodoo 60133 Solid roller cam 253/259*@0.050" - .646/.663" w/1.657 Scorpion Rockers.
Ported Hurricane Intake
PJIII Fuel Injection, MSD and HEI.

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Old 03-12-2013, 08:19 AM
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Absolutely not! The gasket is irellavent, match the heads and the intake to each other not some damn gasket
How do you match the heads to the intake. Is that not what a gasket match does?

Quote:
Originally Posted by Landshark928 View Post
572RWHP @ 6500rpms on a Dynojet NA. 744RWHP with a 200HP shot of N20 running rich. I shift at 7300rpms. Car is about 2800# with me. Will be a little more soon due to roll cage.
Holycrap....thats a lotta power for a car that is only 2800lbs. What size tires are you running? Im running 255/45/17 front and 275/40/17 rear and i think im going to have traction problems with my modest build.
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  #45 (permalink)  
Old 03-12-2013, 08:52 AM
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I have 295 rears now and major traction issues. Still sorting the car out. I am going with 335 rears this spring after I add flares to fit them.
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