My next 454 build
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My next 454 build
Building a test and tune/bracket race 454, and its going to be a inexpensive build. 454 2 bolt block, GM 4.00 crank, GM 3/8 rods, Speedpro 693 hyp pistons, closed chamber GM oval port heads with a Performer RPM intake, 850 AED carb, King of cams 243/243/108 hyd flattappet cam, GM LS 6 stamped steel rocker arms, Its a odd ball combination but hopefully it will deliver at the track. I'm looking to run into the 10s @ Denver. Any ones experiance with with closed chambered big block builds or porting information would be appreciated.
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Re: My next 454 build
Mark, the few I have done I used at 2.19/1.88 combo with a large deshroud plunge cut. Never had them on the bench. Good running combo. I do still have a set of 840's that are roughed out. Not sure how well the larger valves will work due to shrouding. Looking forward to this build! Please post up picks of porting work. Thanks, Charlie
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Re: My next 454 build
Call Verle Stevens in denver machine shop,he has built more chevy motors there than anyone there,he also a racer an has a camaro he races nhra,verle been there 40 yrs building motors...
Re: My next 454 build
I think I will go 1.780/2.190 on the valve size, the exhaust flow has me concerned, but we will see. I have to be able to turn this thing 7000 RPM in the lights.Carnut1 wrote:Mark, the few I have done I used at 2.19/1.88 combo with a large deshroud plunge cut. Never had them on the bench. Good running combo. I do still have a set of 840's that are roughed out. Not sure how well the larger valves will work due to shrouding. Looking forward to this build! Please post up picks of porting work. Thanks, Charlie
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Re: My next 454 build
I would use a solid flat tappet camshaft on this. It will make a bigger (car on track) difference than.... x y z on the valves.
Interesting build.
Interesting build.
Re: My next 454 build
It is interesting. I would use a solid lifter cam but I already have the cam, and cams can be changed. My virgin head cores, 390 castings.F-BIRD'88 wrote:I would use a solid flat tappet camshaft on this. It will make a bigger (car on track) difference than.... x y z on the valves.
Interesting build.
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Racing a NA NHRA stocker should be mandatory before any posting.
Re: My next 454 build
Stopped by storage after the storm to check my parts and snapped a pic of my unfinished 840's. 2.19/1.88. Sorry they still have magnetic dust on them. I am not 100% sure if these have been deshrouded plunge cut or are stock so not much help there. As far as the 1.78 exhaust valve I had a motorhead machine shop buddy that swore 1.8" was THE size for a bbc. He did build some nasty stuff. I should have grabbed the 840's to flow for you but the bench is not set up at the new house yet. Maybe by next weekend. I would cut the seat and port out one exhaust and flow it. If it doesn't pull the number cut it for 1.88 and repeat. With your porting expertise I am sure you can get the 1.78 to pull what you need. Thanks, Charlie
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Re: My next 454 build
Last time I spun hyper pistons to 7000 rpm was on an externally balanced 383 for the old work truck. Had many cracks around the bottom of pin bosses.
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- Alan Roehrich
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Re: My next 454 build
I'm not sure you even need 2.19" intake valves, I think 2.125" might work as well or better in a closed chamber head. I don't think there's a problem with the 1.725" exhaust, but you could go bigger and not hurt anything, even though it may not help, either.
I don't think that's enough duration to run 7,000 and make power, and in light of the weight of big block valve train, I'm not real sure a hydraulic lifter is going to like that RPM anyway. I don't have any confidence in those pistons at 7,000 either. Yes, they may live. Then again, they may not. That's a lot of RPM for the weight. Also, the Speed Pro pistons in general do not gladly welcome much intake duration, or cam advance, especially not with an aggressive lobe profile. I've seen nasty problems with less than 236 degrees of duration, to the point that some of their pistons cannot be cut enough, they go through to the ring groove. I think the last one I fooled with would not accept even a Voodoo flat tappet hydraulic with 233 @ 0.050 and an ICL of 106. Using a 2.125" intake valve might let you get by though.
I don't think that's enough duration to run 7,000 and make power, and in light of the weight of big block valve train, I'm not real sure a hydraulic lifter is going to like that RPM anyway. I don't have any confidence in those pistons at 7,000 either. Yes, they may live. Then again, they may not. That's a lot of RPM for the weight. Also, the Speed Pro pistons in general do not gladly welcome much intake duration, or cam advance, especially not with an aggressive lobe profile. I've seen nasty problems with less than 236 degrees of duration, to the point that some of their pistons cannot be cut enough, they go through to the ring groove. I think the last one I fooled with would not accept even a Voodoo flat tappet hydraulic with 233 @ 0.050 and an ICL of 106. Using a 2.125" intake valve might let you get by though.
Re: My next 454 build
I used closed chamber heads on a 402 truck build, and it tended to ping badly despite being only about 9:1. These heads were designed back when fuels had a lot of octane. I know someone using closed chambers on a 427 bracket motor, and he indicated they improved dramatically with chamber work.
So much to do, so little time...
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Re: My next 454 build
The closed chamber head has plenty of squish and quench, I run them at over 10:1 on pump gas, and with 36 degrees or a little more total timing. But I run them at 0.040"-0.042" piston to deck clearance.
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Re: My next 454 build
With a real aggressive NHRA Stocker style launch (60-330 ft), it will. Soft, marshmallow bracket torque convertors need not apply. Small cam BBC hydraulic Stocker combos run deep into the 10's.427dart wrote:Just don't see it running in the 10's . What weight vehicle is this going in?
The Speed Pros would be my only concern if longevity is of any importance, though.
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Re: My next 454 build
ClassicComp wrote:Like to see this with a gm LS6 cam in it.
That (the LS-6 cam) is pretty close to 244/244/112 0.520". So, it should be somewhat close to what he's going to run, although I'd expect Mike's cam to be more modern and more aggressive.