Running on the Dyno with my LS6 on Friday

[ORIGLS6]

Rob,

I've seen Dan's car and read the numbers but just how close is he to "Pure Stock"? I've always suspected he rides the fence between "Pure Stock" and "Stock Appearing". I know he plays with Dist. curves, etc. and carb tuning, and that's acceptable. Just wondered what else goes on under that hood. Still.........pretty impressive! And much better than what I could do.

Dennis

[mmcporter]

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Rob,

I've seen Dan's car and read the numbers but just how close is he to "Pure Stock"? I've always suspected he rides the fence between "Pure Stock" and "Stock Appearing". I know he plays with Dist. curves, etc. and carb tuning, and that's acceptable. Just wondered what else goes on under that hood. Still.........pretty impressive! And much better than what I could do.

Dennis

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It would be interesting to know what he has for valves, valve springs, cam, lifters, etc. They are all little things but they do add up to a radically different picture. Just look at the killer "L89" Nova run by the Brewers from Georgia. 12's on polyglass with a Turbo 400 tranny. Stock? Ummm errrr....not really...stock appearing? Yes.

[John Brown]

[ QUOTE ]
Just look at the killer "L89" Nova run by the Brewers from Georgia. 12's on polyglass with a Turbo 400 tranny. Stock? Ummm errrr....not really...stock appearing? Yes.

[/ QUOTE ]


If you liked Brewers Nova, you just gotta see what Terry Penningtons Orange 69 ZL-1 clone (S/A) does on white lettered Polys. How about 11.30's ! [img]/ubbthreads/images/graemlins/[/img]

[Chevy454]

I was admittedly one of the ones who said "no way" when Brewer was dropping low-mid 12s on people. Heck, I ran Phil in my first Pure Stock event ever and he dropped a 12.5 on me. I immediately said "no way", as I was running a 427 Camaro and was only running low 13s...of course, I didn't know jack squat about tuning a car, but I figured since I had a 427 and he had a 396 that I should be able to take him. O'contrare mon frere! Granted, he had his engine set back and was admittedly "stock appearing", but my eyes have since been opened, if only a wee bit.

So, we built an engine the way Tonowanda would have back in '69, with the specs way off of what was advertised, just to see what would happen. Well, I've since gone 12.7s@108 with it...if I could hook it, it's got .6s in it, no doubt in my mind. And mind you, this is with 10.2:1 compression, the stock cam put in as original (not retarded), and a heavy automatic Camaro (3700 with me in the seat). That particular engine put up 425+ on the dyno through the manifolds, and I feel better about the timing/jetting I have now than when it spun up the dyno. We basically did it to see if it was possible, and it is, and then some. Pete tried to tell us, but we're Missourians, so you gotta "Show-Me" it can happen.

A lot of what works on your typical "race engine" won't work for what we (Pure Stock guys) do. We're running stock manifolds and 2.5" pipes, so big flow numbers only hurt us because we can't get rid of it. And since we're running the stock cam, heavy duty springs only hurt the cam and add unneeded friction. That's why cam timing and distributor timing are so crucial...we try to sacrifice the bottom end just so we can get rolling and bring it back in on the big end. It's definitely a different mind set, and most engine builders can't comprehend it...I know mine sure has a hard time!

Pete has gone 12.0s in his Pure Stock ZL-1 Camaro, and I watched him put that thing back together at the Certified Stock tech, and you'd be amazed at how tame that engine is. And like John said, Terry's car is a freakin' animal!

[Chevy454]

I tell ya, there's a lot to be said for sweating the little stuff, but Dan's stuff is for sure "Pure Stock". His LS-6 is nothing trick by normal racing standards, just a "blue printed" LS-6...much like the L-72 we're putting together. When you blue print these big blocks to factory specs, you put 'em up in the 12:1 neighborhood compression-wise, which really seems to wake them up. But the key to the whole deal is the cam...and I don't mean a trick grind. Just the stock GM cam, but retarded. What people don't relize is the stock cams are ground 6 degrees advances...good for bottom end power, but makes it a booger to launch on skinny tires. Also, in a "from the factory" engine there isn't enough compression to work "well" with the cam. I've seen 9.8-10.2 compression ratios on stock L-72s! That was the norm, not the "11:1" advertised ratio we'd all like to believe we have. So, when you retard the cam, you basically put it back to "straight up", which kills a little bit of the bottom end (better for launches), but more importantly puts the IVC right where it needs to be with the higher compression (12:1) of the blue printed engine. Simple stuff, but it makes HUGE gains!

(Note: to read more about the IVC & compression, do a search on "comression mapping" on this forum. Some good info posted there.)