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  #16 (permalink)  
Old 06-25-2019, 12:02 PM
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Callies or Scat would be my decision, a balanced assembly from Callies is a good deal, with forged cranks the price is similar to the Scat.

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  #17 (permalink)  
Old 06-25-2019, 01:23 PM
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Quote:
Originally Posted by jjjaffo View Post
I would like to make a correction about the axles. They are 30-spline, not 31 or 33. They were an option for the 8.5" 10-bolt. You can get 30-spline side gears for the 8.5" carrior which are also the side gears in my 7.5" custom Auburn posi. Everything fits like a glove. BTW moser makes these axles too.
Anyway, getting back to the topic at hand, If I do go with the 496 build what are the clearance issues that might arise?
I have 30 spline axles in my 8.5" rear in my S10. Used to have an Eaton clutch type posi until I destroyed the spider gears in a 2900# car with a 383 and slicks. Now I have a spool, c-clip eliminators, and one of those covers that supports the carrier bearing races. A 7.5 posi behind a big block in a heavy car is just waiting to break. Better a 12 bolt or a 9" rear. What I would have done if I didn't have so much money in the one I had already.
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  #18 (permalink)  
Old 07-07-2019, 08:30 AM
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Quote:
Originally Posted by ericnova72 View Post
SCAT is also Chinese sourced forgings and castings, but SCAT does finish machining here in the US whereas Eagle doesn't.

Most all you crankshaft companies entry level stuff is cast or forged in Asia..Callies CompStar, Molnar, Ohio Crankshaft, along with SCAT and Eagle.
The better companies just do the final machining here in the US, so they can control finish quality.

I like SCAT over Eagle....but Eagle has improved from their earlier problems with sizing and finish and don't appear to have the same problems and poorer reputation they once had.

Stay away from CAT though(Cal Auto Transpeed), very poor quality and finish on the cranks I've seen.
Current unknown on exactly how good the quality is happens to be SpeedMaster(ProComp)...some of it is Ok, some is poor, but it is steadily improving in most cases.
I don't personally know anyone who has used their cranks or pistons....but their connecting rods or decent. You can get the rods fairly cheap, but with questionable Chinese bolts in them...by the time you add replacement ARP bolts and pay for a roundness check on the bores after adding the better bolts you are getting close to SCAT or Eagle price territory.

For your plans, the SCAT or Eagle cast crank would work out fine. I recommend forged pistons to everyone who askes about a stroker, I just think it is good insurance as strokers are never driven by a grandma, they are driven fairly hard and forged pistons give you a wider tuning window along with room to grow down the road(nitrous, bigger cam, more rpm) as hot rod stuff often evolves as we change our minds on what we want or get greedy about power.

This is the best deal on stroker kits I've found as it includes harmonic damper and flexplate and has a special forged piston...you can find cheaper but they typically leave pieces out or use lower grade components or hypereutectic pistons to get that lower price point.
https://www.ebay.com/itm/BBC-CHEVY-4...UAAOSwo3pWgk44
ericnova, that's exactly the kind of info I was looking for! I was leaning towards Scat anyway and your post helped me with my decision.
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  #19 (permalink)  
Old 07-07-2019, 09:26 AM
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On the subject of horsepower, I'm having a difficult time grasping the incredible difference between my little 408 BBC and a 496. I think my Cutlass with the 408 has a lot of power and it can blister the 255/60-15 tires at will. Having the typical bench racing mentality I was convinced it had 400 horsepower. However my dynosim software from comp says my engine has 419 ftlbs of torque at 3000-3500 rpms, and 325 hp at 5000 rpms. This seems to be in line with my E.T.s when I had a hair bigger cam in it and the secondaries not opening. 13.5 @ 102 in a 3900 lb car with a 3.42 gear. Also, I have a G*tech ss meter and it says my car has about 235 HP @ 4600 RPMs and 320 torque @ about 3200 RPMs. I assume this is at the wheels. All of this seems to support each other. So, if these numbers are accurate, and a 496 can make north of 500 lbft and 500 hp pretty easily, I just can't fathom what that kind of power would feel like. Any questions and answers would be greatly appreciated.
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  #20 (permalink)  
Old 07-07-2019, 10:11 AM
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Don't get too wrapped up in HP numbers. An engine doesn't produce HP, it produces torque. HP is a mathematical calculation on how fast it can perform the work. More hp means the engine can do the work faster.....

That being said......there's no substitute for cubic inches. There will be some people that say they have smaller engines making more power, but they tend to be either turbo or supercharged, and all you're doing there is artificially making the engine "bigger" by forcing more air and fuel than it can take in on it's own. If you see a smaller engine with a lot of HP, check it carefully as it will tend to have a very high rpm peak for the hp and a very low number for torque, which will make it a slug to drive unless you rev the piss out of it.

As to what it would feel like to have more torque, here's how i'd put it: for example, if you had 300 ft lbs of torque and it pushes you into the seat, then at 500 it might crush you into it....and at 1000 you'll get blurry vision, have difficulty hanging onto the steering wheel, and might even have slight difficulty breathing.....but the other factor to put this into context is the HP factor. Have those torque values, but at low hp, you'll never notice them or they will be modest at best....but have those values with a combo that makes a substantial amount of HP in addition to that, then BAM!!! A big, over the road diesel these days can produce in excess of 2600 ftlbs of torque, but only make approx 650 hp. Yes, that's a huge amount, but how fast will the truck actually accelerate? Not real fast due to weight and other things. But put a 1000 hp, 800 ftlb engine into a car and what happens? INSTANT SPEEDING TICKET!!!

My dragster makes 1510 hp @ 7200 rpm. Torque is somewhere above 1300 ftlbs and that peak is below 5600 rpm. Not sure exactly what it is because when it was dyno'd the sweep started at 5600 rpm and the torque curve was already dropping at that point. So we had to guess. Car weighs 1935 lbs with my fat butt in it and a full tank of fuel. My 60' times are in the 1 second range....It's actually painful to launch the car because it hits so hard when the transbrake releases....and for the first 100 feet or so my vision is blurry and I feel like I'm being crushed...after that I'm still being pushed into the seat pretty hard, but it's not as violent as it is at the launch.....and this is all without the nitrous turned on....add the bottle and it gets worse....MUCH worse.....But damn it's fun!!!!
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  #21 (permalink)  
Old 07-07-2019, 10:12 AM
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Oh, I forgot to mention, mine isn't a 454.....it's a big bigger than that.....
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  #22 (permalink)  
Old 07-07-2019, 02:03 PM
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Intake flow will dictate the power produced, if the head you have now is maxed out you won't make alot more power
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  #23 (permalink)  
Old 07-07-2019, 05:22 PM
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Quote:
Originally Posted by predator carb guru View Post
Don't get too wrapped up in HP numbers. An engine doesn't produce HP, it produces torque. HP is a mathematical calculation on how fast it can perform the work. More hp means the engine can do the work faster.....

That being said......there's no substitute for cubic inches. There will be some people that say they have smaller engines making more power, but they tend to be either turbo or supercharged, and all you're doing there is artificially making the engine "bigger" by forcing more air and fuel than it can take in on it's own. If you see a smaller engine with a lot of HP, check it carefully as it will tend to have a very high rpm peak for the hp and a very low number for torque, which will make it a slug to drive unless you rev the piss out of it.

As to what it would feel like to have more torque, here's how i'd put it: for example, if you had 300 ft lbs of torque and it pushes you into the seat, then at 500 it might crush you into it....and at 1000 you'll get blurry vision, have difficulty hanging onto the steering wheel, and might even have slight difficulty breathing.....but the other factor to put this into context is the HP factor. Have those torque values, but at low hp, you'll never notice them or they will be modest at best....but have those values with a combo that makes a substantial amount of HP in addition to that, then BAM!!! A big, over the road diesel these days can produce in excess of 2600 ftlbs of torque, but only make approx 650 hp. Yes, that's a huge amount, but how fast will the truck actually accelerate? Not real fast due to weight and other things. But put a 1000 hp, 800 ftlb engine into a car and what happens? INSTANT SPEEDING TICKET!!!

My dragster makes 1510 hp @ 7200 rpm. Torque is somewhere above 1300 ftlbs and that peak is below 5600 rpm. Not sure exactly what it is because when it was dyno'd the sweep started at 5600 rpm and the torque curve was already dropping at that point. So we had to guess. Car weighs 1935 lbs with my fat butt in it and a full tank of fuel. My 60' times are in the 1 second range....It's actually painful to launch the car because it hits so hard when the transbrake releases....and for the first 100 feet or so my vision is blurry and I feel like I'm being crushed...after that I'm still being pushed into the seat pretty hard, but it's not as violent as it is at the launch.....and this is all without the nitrous turned on....add the bottle and it gets worse....MUCH worse.....But damn it's fun!!!!
I can't even imagine that kind of power! I get the torque vs rpm thing. I've been in a 956 lbft diesel pick-up and I can beat him all day long- though that truck is really quick lol. Anyway, I use the latest dynosim 6 software to test engine combos before building them, and accurate head flow numbers are a must! The combo I was considering uses AFR 290 oval ports. Even AFR themselves recommended them. With the 112cc chamber I need only a small dome for 10.25 to one comp. This will promote good flame travel across the piston and a tight quench will keep detonation at bay. I'm sure I could go higher but I'm comfortable with these numbers. The cam would be a custom grind 268/274 solid flat tappet 230/236 @.050 with .555/.571 lift. All on a 106 LSA timed straight up. Yes it's a pretty tame cam and yes it's a flat tappet but I like it. With a dual plane, 850 carb and headers w/ mufflers I got 559 LBFT @ 4500 and 562 HP @ 6500. Seems optimistic yes, but a good head can really make a difference. Either way the actual numbers should be well north of the 500 mark and will be a substantial improvement over my little 408! I can look at numbers all day long but until it's tied to my butt dyno I just can't grasp the significance of those numbers.
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  #24 (permalink)  
Old 07-07-2019, 05:52 PM
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Get a hydraulic roller for any BBC, they have always been hard on cams and the roller makes that all a thing of the past.
I did a 496 for a street car with a similar cam but Brodix Racerite heads ported by some famous drag racer, made 590/560 with 10.5 compression and pump gas.
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  #25 (permalink)  
Old 07-12-2019, 06:42 AM
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This has probably been discussed thousands of times, but I have to ask: What power difference can be expected by going to a roller cam? According to David Vizard's teachings, up to about 270* a flat tappet has the same power as a roller. He also says that unless you buy the best of the best hydraulic roller lifters the heavy spring pressures can somewhat collapse them and reduce lift and duration which robs power. When going with a solid roller, depending on the lifter used, it's possible over time to hammer out the needle bearings in the wheel on the lifter. With that said I can't seem to find a cam with the numbers I want in a solid roller anyway. In the flat tappet arena there are many quite street friendly solids for my application. I don't mind the expensive oil and periodic adjustments. Plus when I smack the loud pedal I know it's all there right to redline. On that note does anyone know of a durable rocker? In the dirt track car my friend runs he ruined a set of comp gold rollers. The needle bearings just didn't hold up. I've been running roller tips in my 408 with a hydraulic cam but want a good reliable roller rocker for a solid cam. I know just enough about cams to get myself in trouble so people please enlighten and educate me with your knowledge. I am very eager to learn what others know.
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  #26 (permalink)  
Old 07-12-2019, 07:49 AM
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Durable roller rockers, there are a few.

Crane Gold Race have long been highly respected for durability, as have Harland Sharpe's.
Scorpion is another good one, and are lifetime guaranteed. Scorpionis easy to deal with on returns also.
Howards Camshafts have a good one.
Lunati too.

Comp Cams gold is a relative newcomer....I know my cousin broke one in half, but it was on a big solid roller 588" BBC. He replaced the whole set with Comp
Cams Pro Magnum steel full rollers.

Actually, your friend that beat up a set of Comp Golds could well have a harmonic situation in his valvetrain and that is what pounded the rockers. Not enough spring, running in valve float, or too springy a pushrod will tear up needle bearings in a hurry, regardless of brand. So will poorly set-up valvetrain geometry.

Wrong pushrod stiffness, wrong pushrod length and thus wrong valvetrain geometry is a very commonly overlooked issue. Many guys don't even know to check it or how to set-it up correctly.
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  #27 (permalink)  
Old 07-12-2019, 09:31 AM
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Comp or Crower steel rockers Las and lifetime.
BBC are notorious for eating flat tappet cams, get a custom roller if you have to, hydraulic if you drive it alot.
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  #28 (permalink)  
Old 07-16-2019, 09:09 PM
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Thanks for the info on rockers. However I still have questions about the great cam debate. What's the difference between a flat tappet and a roller as far as power? Yes a roller cam usually has more lift and that's good for upper RPM power. Yes BBC have a habit of munching FT cams. And yes hydraulic cams are more trouble free vs a solid cam. The problem I have is the numbers. Strictly dealing with hydraulics, the big thing has always been the intensity of the cam meaning having more duration at 0.050" for a given advertised duration. Most rollers can't match a flat tappet in that area. But which one for a given duration will produce the best all around power? My problem is I've read a ton of books on the subject but have limited real world experience with these cams. I also haven't seen any cam dyno shoot outs between the two. But even then I don't want peak numbers, I want to see the whole curve. Does anyone know of tests like this I can read about? It all boils down to this: to me it's not worth the extra 5-600 dollars for a roller if the power gain isn't there. I'm here to learn, people, so please educate me on roller cams VS flat tappets of close to the same duration. Help me understand.
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  #29 (permalink)  
Old 07-18-2019, 08:45 AM
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Okay, so I dug a little deeper into the subject. turns out that roller cams have more area under the curve and greater ramp rates which equate to more lift for a given duration. On the dyno some tests between a hydraulic roller and a flat tappet of the same duration @ .050" have shown a roller starts to outperform a flat tappet above about 4500 RPMs. Below that there really is no measurable difference- at least on the videos I watched. It makes sense that the roller starts to outperform the flat tappet due to higher lift which equates to better breathing. One particular video I saw compared cams of 244* duration @ .050" And the difference was a whopping 6 LBFT of torque but a respectable 22 HP for the roller. This was in a 400 sbc and peak power was north of 6 grand which most street vehicles won't be spinning up to. Plus you'd need nasty gears and about a 3500 stall converter. Their words not mine. For those who want to know, the smaller the cam the less the gains appear to be. That being said, and to answer my own question, there appears to be no downside to running a roller other than cost. The benefits are many. Interestingly though, up to a point if you run a solid flat tappet of comparable duration {not the same duration #s due to how solids are measured} against a hydraulic roller the solid flat tappet can run with or even edge out the roller. Just so you know, solid rollers can be incredibly rough on the valve train and are not recommended for extended street use. Another thing to note, if you plan on running a hydraulic roller of decent duration, make sure you buy a quality set of lifters to go with it. The reason being is the heavy spring pressures and aggressive ramp rates can cause lesser quality lifters to bleed down reducing duration and potential lift. This reduces potential power. So, for anyone else who may have wondered about this stuff, for virtually trouble free operation of your engine a hydraulic roller cam is the way to go and that's why people who know engines recommend them. Don't get me wrong, flat tappets are still great performers if your wallet is light, but a fair amount of baggage comes with them.
On another note, I'm a bit disappointed in the knowledgeable people on this site. I got real good advise and information on my thread right up until I asked for a cam comparison. then, CRICKETS....
There has got to be people on this site more knowledgeable than I am on this subject. Seems counter productive to have to answer my own question, but I did learn information that I hope will help other people. If I missed the mark on anything please correct me. I look forward to any questions and comments.
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  #30 (permalink)  
Old 07-18-2019, 09:35 AM
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the roller versus ft debate is pretty short for me--rollers are more durable and can provide more power.
Rick at Isky told me many years ago that his flat tappets made basically the same power in the engines I was building (8k RPM oval, 350cid, 700hp) as the rollers. For street use, GM went roller for durability with modern oils and a little horsepower.
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