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How big is "too big"?

Old Dec 1, 2003 | 07:43 PM
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Default How big is "too big"?

Has anyone tried a 240*+ hydraulic cam in a 346? What is the biggest cam that has been run in a 346 with any success? I am pretty sure that PSJ tried a 244/244 several years ago, maybe he'll chime in with how well/poorly that worked. If it didn't, I wonder if todays cylinder head technology would help it any. I also think that, with all the recent big dyno numbers and the selling power and bragging rights that the big peak numbers provide, that someone is/will be using a huge cam like this, and willing to give up lowend torque and power for big numbers from 5000+ RPM.

With a good set of heads (TEA, AS, PP, MTI, Cartek, etc) that flowed 300+ cfm, a big cam like this may be able to breathe at 7000 rpm, right? Would the intake be the limiting factor? I wonder why someone hasn't tried a HUGE cam with a 1000+ rpm idle, manual brakes, trying to get the biggest dyno numbers, or the lowest ETs. High HP SBCs routinely use camshafts bigger than 270* @ .050 , and a good set of ported LS1 heads flows right there with some of the best SBC heads out there.

Just thinking out loud, Shawn
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Old Dec 1, 2003 | 08:39 PM
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I know that PSJ was running a 244/244 cam in his ARE 422 cubed ironblock car and i don't think he tried this on a stock cubed motor (346). I certainly am no expert but i am running that same cam in my MTI 427 C5R motor through my A4 and its fairly tame with the extra cubes and its my understanding that this big of cam on a stock cubed motor not only would have really shitty low end and mid range power, etc. but would also be unstreetable in that it would be stalling out at lights, etc. and would have to be spun to 7000+ to get the full benefit of the big stick! I am certain many much more knowleagable than i will chime in here. I know the tuners have pushed the limits to see how big you can run on stock cubes and the big boy cams your hearing about these days are pretty much at that limit and the cam you mention would make less power throughout the entire rpm band with stock cubes vs. the big boy successful cams right now, ie-LGM G5x2, x3, TSP 231/237 cam, MTI x1, etc., etc.

Last edited by MTI 427 C5 Roadster; Dec 1, 2003 at 09:20 PM.
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Old Dec 1, 2003 | 09:05 PM
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I'm running a 234/246 in my 347. First time out netted 11.0@123. The heads are 2 year old GTP stage 2's. I know for a fact nobody else has the 246 XE-R lobe b/c comp told me they had never done one before. There's alot left in this setup and I am only looking for good numbers with nitrous. Power seems to drop off right at 7k. I haven't dynoed it yet or gotten a chance to really mess with the timing and A/F much.
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Old Dec 1, 2003 | 09:10 PM
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I'm guessing that the Cartek, LG, and MMT big grinds are pushing the envelope (plus other shops), so we're still finding out what works.

I ran the 244/244/112 in the old 422ci iron block.

Back a few years ago I had a 236/240//111 in a 346ci block with I think Comp 977's. I think it was in straight up, the car pulled great above 6000 but had no midrange. I would not go by my early example I never dynoed it so there is no strong conclusion to draw.

I think if folks want to get really on the edge, we'll see some 24_/23_/110 stuff or 24_/24_/110 stuff that works with big gears, 5000 stalls and 7000-7200 shiftpoints assuming that the FAST LSX intake is all that it's supposed to be.
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Old Dec 1, 2003 | 10:19 PM
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I also think that the intake would be the reason why there is a camshaft limit on LS1s. It would be nice if someone came out with a open plenum straight though intake like a victor jr. with a T/B on top instead of a carb ofcoarse. The cowl would have to be cut for sure, but with a straight though shoot at the intake valves and the high flowing heads we have now, we might be able to use like a 260/270 on a 108 solid roller with great success. we have a long way to go till that happens but maybe the day will come. the r@d has already been spent on these kinds of intakes so why not. the LSX looks great but i bet my victor jr flows more.
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