402A2LUN vs. Lunati 60240 - Chevelle Tech
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post #1 of 15 (permalink) Old Jan 12th, 20, 10:56 PM Thread Starter
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Mike
 
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Anyone have experience running the Lunati SFT 402A2LUN (272/282, .238/.248, .550/.570”, 112/106) or 60240 (266/276, 233/241, .570/.590, 110/106) in a 10:1 496, big valve ported 049 heads, dual plane intake and 750 Holley?

Looking to run with stock stall and 2.56 gears @ 4050 lbs. The stock converter and gears is the reason for the smallish cam.

Currently have 10.5:1 467, 781 big valve heads, with Summit HFT K1303 (304/316, 238/248 @ 0.050”, .540/.540 114/109) cam which runs really well for what it is, looking to knock off about 1 second (runs about 1.99/12.9/107.5 right now). Trap rpm at 114 mph will be about 5400.

I’m conflicted right now, part of me is saying run the same Summit cam (because I need more torque to get out of the bottom), even though the lobes are “lazy,” since the lobes are less likely to have issue (and despite the fact a 496 needs about 15 degrees more at 0.050” to peak at the same rpm, given the same head flows).

Part of me is saying, tack on 14-16 degrees @ 0.050” and don’t worry about getting out of the bottom, the additional 1/4” stroke will bring the torque I need.

My compromise is the 402A2 or 60240, the more aggressive lobes, even though the 0.050” durations are the similar or even less, I should have all the torque I need and much improved top end.

What say those who have run either or these cams? I think like the idea of 112 or 114 LCA to smooth out the torque curves but I don’t believe I’m well informed enough to ask for the change.

1981 Malibu wagon
406/350/4.10
Best ET NA 12.20 @ 110
Best ET w/N2O 11.47 @ 117
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post #2 of 15 (permalink) Old Jan 13th, 20, 9:46 AM
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Re: 402A2LUN vs. Lunati 60240

I bet there would not be 2 tenths difference between any of those cams and including the one you currently have.

It is so hard to run the gear you have at that weight and produce a low et.

I feel you will need to really build a lot more torque to make your 1 second quicker goal.

Slap in a 3.08 gear and go quicker than any cam swap in the above will give you.

If I had your cam and just had to try another cam I would probably go much more duration and a tighter LSA as it looks like you can't get the low 60 foot time possibly it hooks very well and the TQ ain't there.

But if that 1.99 60 foot is from spinning then the tighter LSA may hurt as it will hit harder right out of the hole.

Yea I know it is valve events not LSA.
Saying earlier closing intake valve would make it come on harder out of the hole.

I had 2.56 gears years ago and went to 3.08 and it was like a different car..I actually got 2 MPG better with the 3.08 as it was not laboring coming off a stop so i did not have to add as much throttle.
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post #3 of 15 (permalink) Old Jan 18th, 20, 2:49 PM Thread Starter
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Re: 402A2LUN vs. Lunati 60240

Quote:
Originally Posted by jeff swisher View Post
I bet there would not be 2 tenths difference between any of those cams and including the one you currently have.

It is so hard to run the gear you have at that weight and produce a low et.

I feel you will need to really build a lot more torque to make your 1 second quicker goal.

Slap in a 3.08 gear and go quicker than any cam swap in the above will give you.

If I had your cam and just had to try another cam I would probably go much more duration and a tighter LSA as it looks like you can't get the low 60 foot time possibly it hooks very well and the TQ ain't there.

But if that 1.99 60 foot is from spinning then the tighter LSA may hurt as it will hit harder right out of the hole.

Yea I know it is valve events not LSA.
Saying earlier closing intake valve would make it come on harder out of the hole.

I had 2.56 gears years ago and went to 3.08 and it was like a different car..I actually got 2 MPG better with the 3.08 as it was not laboring coming off a stop so i did not have to add as much throttle.
I know what you're saying Jeff. I'm just overthinking things while waiting for my heads. I've been going nuts playing with Desktop Dyno.

Is it a fluke the 467 runs as well as it does now with 2.56 gears/stock stall and a cam such as the Summit 238/248 .540/.540 cam, which should certainly be too large for a stock stall? The 1.99 was not spinning...dead hook at 4240 lbs (my uncle riding shotgun) 13.077 @ 107.56 (872', 72' DA).

I did misspeak previously about compression, my 467 is closer to 10.5:1 (28cc dome).

My first car ('79 Cutlass with Chevy 350), I swapped from 2.29 to 3.23 - it was like a new car. Never raced with the 3.23 gears though, I sold it to a friend after I swapped to the '75 Olds 8.5" 10-bolt w/4.10 gears. I'm committed to at least one more season on the 2.56 gears in the MC.

1981 Malibu wagon
406/350/4.10
Best ET NA 12.20 @ 110
Best ET w/N2O 11.47 @ 117
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post #4 of 15 (permalink) Old Jan 18th, 20, 4:43 PM
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Re: 402A2LUN vs. Lunati 60240

I do not think it is a fluke ..you have a lot of cubes and many people can't tune what they have and that tune can make a huge difference.
If it was my car I would try a different intake as I really do not mind changing intakes and distributors.

What would I install.... Tall Tunnel-ram and I would top them with 2 edelbrock 600 1405 carbs. probably because I have a lot of them and a couple tunnel-rams.

Every time I stuck a tall dual 4 tunnelram on an engine it went quicker and made more power everywhere.
Last one was a 396" 11:1 compression [email protected] .050 108 LSA .544" lift.
Zips quickly to 7000 rpm.
Buddy has it in a truck 4200 lb with peg leg 3.08 gear.. with the single 4 it went 13.50's.

We are converting the points to electronic soon and will run it again at the track.

I picked up 53 wheel HP everywhere on a small block going from the RPM intake to a tall tunnel-ram and 2 carbs.

No hood means a little lighter unless you are keen on punching a hole in a good hood.
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post #5 of 15 (permalink) Old Jan 18th, 20, 5:22 PM
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2:56, seriously ?
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post #6 of 15 (permalink) Old Jan 18th, 20, 6:18 PM Thread Starter
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Quote:
Originally Posted by Reelysalty View Post
2:56, seriously ?
Yes.

When you drive a 467 with a reasonable cam, the 2.56 gears feel like a 350 with 3.42s. The car drives well.
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1981 Malibu wagon
406/350/4.10
Best ET NA 12.20 @ 110
Best ET w/N2O 11.47 @ 117
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post #7 of 15 (permalink) Old Jan 18th, 20, 6:26 PM Thread Starter
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Quote:
Originally Posted by jeff swisher View Post
I do not think it is a fluke ..you have a lot of cubes and many people can't tune what they have and that tune can make a huge difference.
If it was my car I would try a different intake as I really do not mind changing intakes and distributors.

What would I install.... Tall Tunnel-ram and I would top them with 2 edelbrock 600 1405 carbs. probably because I have a lot of them and a couple tunnel-rams.

Every time I stuck a tall dual 4 tunnelram on an engine it went quicker and made more power everywhere.
Last one was a 396" 11:1 compression [email protected] .050 108 LSA .544" lift.
Zips quickly to 7000 rpm.
Buddy has it in a truck 4200 lb with peg leg 3.08 gear.. with the single 4 it went 13.50's.

We are converting the points to electronic soon and will run it again at the track.

I picked up 53 wheel HP everywhere on a small block going from the RPM intake to a tall tunnel-ram and 2 carbs.

No hood means a little lighter unless you are keen on punching a hole in a good hood.
I’m a fan of tunnel rams the runner length is like magic. Unfortunately, I’m not a fan of cutting a hole in the hood or going hoodless.

I’m going to go dual plane on the 496, like I have now before eventually switching to the dual quad intake I picked up. I know dual quads aren’t the hot ticket for performance, but I’m going for a retro look with this car. Still looking for one more Carter 625 locally to complete the setup.
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1981 Malibu wagon
406/350/4.10
Best ET NA 12.20 @ 110
Best ET w/N2O 11.47 @ 117
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post #8 of 15 (permalink) Old Jan 18th, 20, 10:45 PM
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Quote:
Originally Posted by dragginwagon406 View Post
Quote:
Originally Posted by Reelysalty View Post
2:56, seriously ?
Yes.

When you drive a 467 with a reasonable cam, the 2.56 gears feel like a 350 with 3.42s. The car drives well.
So, you have managed to neuter a 467 so it thinks it’s a 350 ?
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post #9 of 15 (permalink) Old Jan 19th, 20, 9:24 AM Thread Starter
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Quote:
Originally Posted by Reelysalty View Post
Quote:
Originally Posted by dragginwagon406 View Post
Quote:
Originally Posted by Reelysalty View Post
2:56, seriously ?
Yes.

When you drive a 467 with a reasonable cam, the 2.56 gears feel like a 350 with 3.42s. The car drives well.
So, you have managed to neuter a 467 so it thinks it’s a 350 ?
I look at it differently, I’ve managed to match the 467’s torque to the available traction from regular street tires. I’ve also done it using swap meet intake and heads, factory pushrods, guide plates, rocker arms, and a $105 cam and lifter set. That’s a relative value.

Could it go much quicker with increased stall converter and gear, you betcha. But it would not be as street or highway friendly and I’d need to seriously look at suspension mods and sticky tires. As it is now, I can get in and drive anywhere, empty the trunk and, in good air, run high 12s. And, I can do it with 50K mile tires that I drove in on.

To me, that is success. But we Americans always want more, myself included. If high 12s is good within the given constraints, high 11s would be better. So 11s time slips are the new goal.

1981 Malibu wagon
406/350/4.10
Best ET NA 12.20 @ 110
Best ET w/N2O 11.47 @ 117
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post #10 of 15 (permalink) Old Jan 20th, 20, 10:45 AM
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Re: 402A2LUN vs. Lunati 60240

If I used used the Wallace calculator correctly you need 100 more HP to go a second faster, outside the tinkering range you need big change, put big bore and stroke 4.6 X 4.25 and 10.5 to 1 CR into your software with your current cam and then model the others
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post #11 of 15 (permalink) Old Jan 20th, 20, 10:39 PM
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Re: 402A2LUN vs. Lunati 60240

Reading this reminded me of my 78 Nova and at one time I stuck in some 2.29 gears Yes 2.29 thinking my MPG from the 3.70 would get way better.
It ran 12.55 with the 3.70 gear and a comp Magnum 270H [email protected] .050 Ported and milled 186 heads RPM intake and 750 Carter competition series AFB.

Now it was very high compression and 245PSI cranking pressure but very happy with 91 or 93 octane.

I got in a race with a buddy that had a WS6 TA it went 13.8's I could beat him by 2 lengths with the 2.29 gears.
That was about 1/4 second quicker than his ride.

Yea not the 12.55 it was but it sure was fun busting rubber at 95 MPH going into second gear on the TH350.

At first my MPG was 15-18 with the 3.70 gears depending on how hard I drove it.
The change to 2.29 gears I got 8 MPG.. yes 8 mpg.

After the first tank I realized my cruise RPM was below 1700 rpm most of the time.. My timing curve was not all in until 2400 rpm.
I had to use some very light springs I got from the guts of an old cash register. and I had to weld a bead on top of my advance weights to make the timing all in before 1600 rpm.

That was fun and at idle the advance curve came in and out if I had the idle below 900.

Those 2.29 gears came from a 1978 or 1977 Full size Cougar XR7 with 351 engine.
Way fun gear to play with.
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post #12 of 15 (permalink) Old Jan 22nd, 20, 11:23 AM
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Re: 402A2LUN vs. Lunati 60240

open your ring gap and run an underhood weiand blower

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post #13 of 15 (permalink) Old Jan 22nd, 20, 2:12 PM
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Re: 402A2LUN vs. Lunati 60240

Say Why And.

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post #14 of 15 (permalink) Old Jan 22nd, 20, 3:16 PM
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Re: 402A2LUN vs. Lunati 60240

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Originally Posted by Reelysalty View Post
2:56, seriously ?
Why not,I have a run high 12's with a 2.56 gear in my LS6 car years ago. On a DOT tire too.
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post #15 of 15 (permalink) Old Jan 22nd, 20, 3:17 PM
 
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Re: 402A2LUN vs. Lunati 60240

Quote:
Originally Posted by dragginwagon406 View Post
Anyone have experience running the Lunati SFT 402A2LUN (272/282, .238/.248, .550/.570, 112/106) or 60240 (266/276, 233/241, .570/.590, 110/106) in a 10:1 496, big valve ported 049 heads, dual plane intake and 750 Holley?

Looking to run with stock stall and 2.56 gears @ 4050 lbs. The stock converter and gears is the reason for the smallish cam.

Currently have 10.5:1 467, 781 big valve heads, with Summit HFT K1303 (304/316, 238/248 @ 0.050, .540/.540 114/109) cam which runs really well for what it is, looking to knock off about 1 second (runs about 1.99/12.9/107.5 right now). Trap rpm at 114 mph will be about 5400.

Im conflicted right now, part of me is saying run the same Summit cam (because I need more torque to get out of the bottom), even though the lobes are lazy, since the lobes are less likely to have issue (and despite the fact a 496 needs about 15 degrees more at 0.050 to peak at the same rpm, given the same head flows).

Part of me is saying, tack on 14-16 degrees @ 0.050 and dont worry about getting out of the bottom, the additional 1/4 stroke will bring the torque I need.

My compromise is the 402A2 or 60240, the more aggressive lobes, even though the 0.050 durations are the similar or even less, I should have all the torque I need and much improved top end.

What say those who have run either or these cams? I think like the idea of 112 or 114 LCA to smooth out the torque curves but I dont believe Im well informed enough to ask for the change.
If your keeping the car, I would highly recommend going roller.

Chris Straub
Mfg Performance Parts

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Why is it we never have time or money to do it the right way in the beginning but we always have time and money to do it over again?
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