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Discussion Starter #1
I finally got to see my 496 run that Chris Straub cammed for me. It is a S/R Straub custom cam, with GMPP oval 2.25 x 1.88 out of the box heads. Running about 10.6 to 1, forged assembly. The ovals cc'd at 111cc. It has an Edelbrock Performer RPM intake. (Intake and heads painted Chevy orange). Could pass for the 396 that I will be replacing. The carb we used was a Holley 750 vac sec-3310 that I had for my 408, that ran rich. It has upgraded Proform main body and baseplate. The headers on the dyno are 2.25", much bigger than what I will run(1.75"). This setup ran 557HP and 567TQ on the very first day (yesterday, break-in). Today we ran it again, after letting it sit overnight and cool down, etc, after checking the lash and warming it up. 587HP @ 6200 and 590tq @ 4100. The tq curve is exactly what we wanted, 545+ at 3200. 506 at 6000 . Then we put on a quick fuel 850 that is supposed to flow 930cfm. We hit 604Tq @ 3400 and 599.1HP @ 5800!!!
FYI, we were running a dyna gear timing gears, they sure seem like junk. The c-clip was grinding on the gears. We replaced it with a Cloyes timing chain. No problems. I am also running an ACCEL HEI dist.
I am very pleased with the numbers.
Thanks Chris for specing the cam.

If I had known that my 750 vac secondary was going to run that good, I would not have bought the 930cfm.
 

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I think the 930 is a better carb, look at the spread that resulted from changing, dropped peak TQ 700 rpm and gave a 2400 RPM spread. This will make for a better all around engine. By the way, nice numbers!
 

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Discussion Starter #3
I agree with what you say, but the Quick Fuel 850 (930cfm) was not idling very well. I could definetly use it at the track and gain some mph/et. Anybody mess with these carbs?
 

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Nice build, probably just need a little idle mixture screw setting.
Quick fuel is same as holley........yes a few people around here mess with them, :)
 

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I am a little behind in my abbv. What is GMPP?

Love the numbers you came up with...I can't wait to get my 496 together.:thumbsup:
General Motors performance parts, they are mad by eddelbrock if memory serves.
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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Nice, you're going to like the way that thing drives. The smaller headers are going to boost Tq throughout the midrange.
 

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Discussion Starter #10
I am ready to swap motors. This 496 build started because my original #'s matching 396, would not stop leaking like the EXXON Valdez (for you old timers). Anyway this 496 went on the engine dyno, tuned it, found a problem with the timing gears, its ready to drop in. With no more oil leaks. I am stoked. My car still needs alot of work, but I was really bummed because my 396 has been running since the end of last year, just leaking oil, hated that. Now I can drive around with a 600hp 600tq motor, with no oil leaks. I don't care about the rest, at least I can drive it while I am working on it.
Think about what the internet provides us nowadays, with so much info at this site, experience, recommendations, testing, etc. My last motor that I had built here in the Dallas area, was a disappointment. I may have to get with Mr Chris Straub and get me another cam for my truck, to get it running correctly. He is the man. If it was not for the internet and this Chevelle website, I would not have know who he was. The cam he did for this was 100% worth the $400 he was asking for. That is one place I am glad I splurged on instead of buying an off the shelf cam.
 

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Discussion Starter #12
I agree on the 2" headers. Just have to wait till the funds are available. In the mean time I can at least drive it.:beers:
 

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Not sure yet about the throttle response, still working on swapping the motors. Have a 15yr old daughter to take care of. She wants the Chevelle, but can't get her to turn some wrenches, you know what I mean!!
Chris, I sent you an email with the dyno numbers attached, not sure how to attach documents on this website.
 

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I ran those same heads on a 460" motor w/ 233/236 hyd roller cam. Ran it with 1.75" headers. The GMPP/Ede heads have a raised exhaust port floor. Even a 1.75" header tube was significantly larger than the exhaust port. I doubt you will see much/if any loss in mid-peak power between a 1.75" or 2" header on that combo. My guess is the cam has a 10* split to help on the exhaust side anyway.
 

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nice...I have a new 496 in my 67ss. the build is very similar but it is running a comp cam xr290s solid flat tappet. I have a 750 vs 3310 carb that I was planning to use. the motor came with a gool ol 850 dp carb. putting the 750 on there is like throwing a wet rag over it. the 850 makes a huge positive difference - it does like the petrol though. imho these stroker motors (mine is a bored and stroked 427) can take as much carb as you can put on them.. mine makes 607 hp at 6200, 627 ft/lb at 4500....the back tires are not big or sticky enough.....have fun !!
 

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Not sure yet about the throttle response, still working on swapping the motors. Have a 15yr old daughter to take care of. She wants the Chevelle, but can't get her to turn some wrenches, you know what I mean!!
Chris, I sent you an email with the dyno numbers attached, not sure how to attach documents on this website.
Got the files thanks, she is pancake flat when it comes to the power curve. Good luck with tires. Let me know how throttle responsive she is..
 
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