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Discussion Starter #1 (Edited)
Trying to help a friend out. He has a 496 bbc in his 68 camaro with 4.56 rear. Th400 tranny with 5800 neil chance converter. The engine has 13-1cr with a 285 [email protected], .730 lift 114 lsa SR custom cam. Brodix track1 heads, vic jr intake, Holley 950 hp carb.
I don't have the dyno sheets here but it made 725 hp at 6800??? While this sounds good it really doesn't run that good. Last time at the track I ran a 11.33 with my junk and he ran a 11.1x. My 351 beats him to 330' but he comes around me at the 1/8th.
It seems to me that the midrange is lacking and I wonder if he has too much cam for his smaller heads/ intake/ carb??? He's looking at a cam change , but I wonder if bigger heads, super vic intake and dominator carb might be needed to feed the 496.
Any ideas? Thanks
 

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Discussion Starter #3
It needs something around a 278/288 @.050" on a 112.

I'd need to see the complete flow numbers to be exact.
So he's not far off with 286 @.50 with 114 lsa. I think the brodix Track 1 heads he has flow 330 @ .700 according to the website. Doesn't seem to great for 496 ci.
Am I right in thinking that the heads intake carb are a bit too small?
 

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Discussion Starter #4
Ok, mybad, he has Brodix Race Rite 270 oval port heads that flow 340 @ .700. He is now looking at AFR 335 heads. Is he headed in the right direction or would the 335s be too much?
 

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Just curious, what's his MPH?
 

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With those heads on a 496 it will need a split of at least 14 degees at .050". The engine is smoothering itself as the rpm grows because it can't get the exhaust out the pipes. I would say the car gets to a point and then just hits a wall. If he wants to prove my thoughts loosen the intake lash .008" and tighten the exhaust .008" and run the car 1 x down the track.

The 114 Lobe sep is WAY wrong for the rpm range and piston speed. That engine needs to be around a 108 or 109 I feel.
 

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Discussion Starter #11
Actually the engine doesn't seem to wake up until it hits 5-6000ish rpm. No midrange tork. It seems to me that with the smaller heads and ci that it should make a buttload of tork. Just curious, why do you feel 108 lsa would be an improvement??
 

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Actually the engine doesn't seem to wake up until it hits 5-6000ish rpm. No midrange tork. It seems to me that with the smaller heads and ci that it should make a buttload of tork. Just curious, why do you feel 108 lsa would be an improvement??
His powerband looks like the Rockies, not a plateau. Runs like a 2 stroke. Trust me try the lash adjustment it is free.
 

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My experience. I had a 12.7 to 1 468 with a crane 268/[email protected] 649/669 solid flat tappet. Merlin Iron rect. port heads. Victor 1050 dominator. Went 10.50's all day long in a 3600 pound chevelle with a 4.30 gear and a way to tight (3600) stall. 2" off the shelf comp headers. 4" exhaust to the rearend with flowmasters. If it was me I would play with lash (its free). Then I would suggest it needs a bigger carb.And depending what this car is running for exhaust, I would make it bigger. Try the car uncapped if it is running exhaust.
 

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Discussion Starter #16
That's why I said in needs less duration on a tighter LSA.
If it had less then the 5,800 stall, I'd go even tighter then 112 on the LSA
Ahh- I understand now, I was thinking that the difference between 112 and 114 lsa wouldn't be that substantial.
The car has Hooker Headers and mufflers, no tailpipes. I texted him this am and told him to remove the mufflers and give it a try. I will also suggest the valve lash trick.
Thanks
 

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The engine doesn't turn on until 5 or 6Krpm probably because the intake runners on those heads are way to big for that engine,there is no way that thing will do anything down low or mid with runners that size. 310cc/315cc work very well on a 496bbc. imho what you've got going on is exactly that! bigger is not always better, sometimes less is more. just sayin......
 

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My 496 with ported dart 345s a dart intake 1050 Dom 12.8 -1 can was 808 -765 on 112 in @ 109 280-292 @.050 5500 9 inch converter timing locked at 40 2 1/8 headers 4 inch dynomax bullets turbo 400 4.86 gears 3500 lbs 57 Chevy went 9.70 @138 1.32 60 foot ....best 60 was a 1.28 off trans brake car wheelies like crazy sometimes 120 feet out shift to second in the air and 60 foot with back tires 1.41......everyone said it wouldn't run and were shocked at the results.....everything I was told was too big and wouldn't her out of its own way.....first pass 5000 chip on 2 step and almost on the bumper lmao
 

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What are his 60 foot times, shift points, transbrake or footbrake, true stall? 725hp in an all steel camaro aluminum headed bbc motor weighs very near 3520 with me 185 lbs. All steel 69 camaro super stocker ran 10.0s with 675 dyno'd hp at 7000 shift. 1.32-1.33 60 times. Need a ton more info. I see a ton of people on here say they have 800hp and run 11.70s.

Many reasons why that is the case.

1. They are truly afraid to run the car as intended.
Don't want to hurt motor etc...I have seen this many of times. They put a diff driver
In the car and it magically stands on the bumper and runs it fastest times ever. Real hp can be scary to some people.
Went to racing school and had buddies who ran 11-12 second cars get into the schools super gas car. After letting
Go of brake at 4k and really getting whacked, they wanted nothing to do with it. Car would go 9.15 off the stop.

2. If that motor is really 725hp, then their mph would be in the low 130s. MPH is horsepower..........

3. Suspension setup is all messed up.

4. Was the converter built for the motor.

5. Personally I would pull the motor and have it re-dyno'd by someone else. Half a day dyno will cost $400.

6. After re-dyno. Have the converter sent in to be opened and setup per the dyno sheets.

7. Having 5-6 completed will save him thousands in the long run.

8. Details or video of his runs. 1/8 times, does it wheelie or roll off the line.
 
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