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  #1  
Old 06-20-2018, 04:07 PM
Hubert Hubert is offline
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Default 396 realistic HP, sizing fueling

I am starting the planning on my Chevelle, because in about a month or so I should be able to get started on the restoration. For that -

I need a realistic upper estimate for what my 396 puts out. I haven't finalized the parts yet, but will be running a stock block with a roller cam. This is the cam I'm considering. I may get aluminum heads and intake. The reason for this is...

Has anyone had any experience with Holley's Sniper EFI system? My main experience with carbs is springs and ball bearings in the far corner of the garage, so I'm thinking that rather than trying to find someone who even knows what a carb is, much less how to set one up, to go with one of these self-contained systems. The systems are sold by HP ratings and I want to make sure I don't get too large or too small a system for it.

So, if anyone knows what a 396 really makes, with a few minor upgrades, I'd appreciate it.
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1970 Chevelle SS396, TH400 trans
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Old 06-20-2018, 06:45 PM
FlintTony FlintTony is offline
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Before anyone can give even a ballpark number, some things must be factored in. Compression ratio, valve size, flow numbers for the aluminum heads, camshaft profile, which exhaust system will be installed. Will it be a stock stroke crankshaft?

Wow, 17K original miles? What's the backstory on your car? Sounds interesting. Good luck with the build!
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  #3  
Old 06-21-2018, 02:43 PM
carpoor carpoor is offline
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This is the one I bought for my folk's car...

https://www.summitracing.com/parts/sne-550-516

The engine is a .040" over ATK 454, .100" dome pistons, hyd roller, fully CNC'd AFR 265s.

The system I bought says good to 650 HP, will be more than adequate for their 454. I estimate their engine around 550-575 @ the flywheel.
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1972 SS 454 Chevelle LS5/M21/12 bolt 3.73 posi
1969 Malibu factory L48/M20/12 bolt 3.31 posi
2001 Silverado RCSS LQ4/80E/4.11 posi. Cam'd & bolt ons
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Old 06-21-2018, 09:02 PM
Hubert Hubert is offline
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About the only definite I can put in is it's the stock stroke and I'm not building an all-out racing engine. This car will be intended as a cruiser. I've not really decided on a lot of the parts except perhaps the cam I linked to. I don't even know which 396 I have in there, only that it's the one that came in the car. The fuel injection I'm looking at supports, depending on model, 350HP, 600HP, 1500HP. I'm leaning towards the 600HP being the one I need since I'm pretty sure I'll be putting out more than 350HP when it's all said and done seeing as the bone stock was capable of up to 375HP. My main concern here is I don't know how much GM under-rated their engines and since I do plan on upgraded parts I feel that I might be pushing the limits with 600HP. The problem here is, I just don't know. When the engine comes out I'll know more but until then...

The Chevelle is actually the second project in line here so I have a little time before I start buying parts. First project, refurbishing my mother's pickup, which should take me a month or so to complete depending upon weather. It's getting a new engine, maybe a new rear diff, new seats, shocks, steering rack, paint job, and a few other knick-knacky things repaired.

On the car, as I was told, the original owner (in Arizona) bought it for his wife. After a couple of years she stopped driving, so he put it back for his daughter. When his daughter was old enough to drive, she didn't want to drive "some dirty looking old car" because she wanted one of the new 3rd gen pastel Camaros. About that time my dad was driving through and saw the car was for sale. He bought it and dragged it back home. He worked on it off and on, until he took a job several states away. My mother bought it from him (divorced a number of years) and she kept it in her garage. The car was only driven very occasionally over the years. She decided she didn't want the car anymore, so she gave it to me. So, there you have it, the story of the 17K mile SS.
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1970 Chevelle SS396, TH400 trans
Cherry red / white stripe exterior, black vinyl interior 17K original miles
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Old 06-21-2018, 10:50 PM
carpoor carpoor is offline
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Prior to 72, GM over rated their engines. There was a story about it in Super Chevy about a decade ago. A 70 LS6 454 450 HP only made about 280 to the wheels. (18-20% drivetrain loss means that it really only made about 340-360 real world HP) They used gross HP rating vs the current SAE net ratings.

A healthy, modded 396 should made 450 HP no problem, maybe more. You'll be more than safe with the 650 HP unit.
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1972 SS 454 Chevelle LS5/M21/12 bolt 3.73 posi
1969 Malibu factory L48/M20/12 bolt 3.31 posi
2001 Silverado RCSS LQ4/80E/4.11 posi. Cam'd & bolt ons
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Old 06-22-2018, 03:08 PM
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RBeckman RBeckman is offline
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I can tell you that when I rebuild my 396/325 I just changed the cam to a RV cam, had the original heads cleaned up and had the original quaderjet gone through and a Corvette aluminum intake and added headers and it made 410 hp and 454 torque @ 3200 rpm for torque on the engine Dyno. Also a stock HEI GM ignition.

The intake was a 427/390 out of 69 so I had to put a riser on for the linkage to work.
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Old 06-22-2018, 05:53 PM
Hubert Hubert is offline
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Excellent, thanks folks. Sounds like that midrange unit will fit the bill then.
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1970 Chevelle SS396, TH400 trans
Cherry red / white stripe exterior, black vinyl interior 17K original miles
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  #8  
Old 06-22-2018, 07:22 PM
FlintTony FlintTony is offline
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Neat story Hubert. Sounds like it should be rust free. A big bonus for you.

I had an L78, 69 Chevelle with an all original driveline. The factory rated it at 375 HP. It actually "felt" like it had more HP than that. I compare that feel to the cars that I have now. Both Chevies have 427s in them One dynoed at 450 and the other one is a hair over 500. A pretty decent build for you to consider would be something along those lines. You would have to drop the compression ratio a little to run on the shit gas that we have now.
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Old 06-22-2018, 10:26 PM
carpoor carpoor is offline
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Someday, I would really like to pull the LS5 out of my 72 and stick it on a dyno. Most likely will have to settle for a chassis dyno instead. I had a spare LS5 that I was going to put together to stock specs. None of the trick stuff mine has... oiling, valvetrain, etc. Just wanted to see the difference.
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1972 SS 454 Chevelle LS5/M21/12 bolt 3.73 posi
1969 Malibu factory L48/M20/12 bolt 3.31 posi
2001 Silverado RCSS LQ4/80E/4.11 posi. Cam'd & bolt ons
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