#21  
Old 10-02-2021, 01:43 PM
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according to an email i got from Dave as of earlier this year SD does not do the heart shape chamber mod to E-heads anymore. the link above is for the Eheads with the heart shaped chambers & then SD's porting work.

  #22  
Old 10-02-2021, 03:13 PM
Randy Allen Randy Allen is offline
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I sent an email to Dave to inquire about opening up the 72cc chambers to around 100cc’s. That would drop my compression to 9:18. If I wanted to put in a 4.5 stroke crank (Scat forged)and get 495ci the compression would bump right back to 9:65 ish. Assuming I had 325 cfm E-heads and the 4.50 stroke I suspect with the same hydraulic cam (237/244 on a 112 lobe separation with .533/.549 lift at 1.65) it might boost horsepower from ~500 to ~580. I have no idea how much more power the e-heads will make over the 6x-4’s with that cam(or a very similar hydraulic roller). Any thoughts on power and reliability of a 4.25 versus 4.5 stroke? This will be road raced and street driven with a 6-speed.

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Old 10-02-2021, 03:32 PM
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I sent an email to Dave to inquire about opening up the 72cc chambers to around 100cc’s. That would drop my compression to 9:18. If I wanted to put in a 4.5 stroke crank (Scat forged)and get 495ci the compression would bump right back to 9:65 ish. Assuming I had 325 cfm E-heads and the 4.50 stroke I suspect with the same hydraulic cam (237/244 on a 112 lobe separation with .533/.549 lift at 1.65) it might boost horsepower from ~500 to ~580. I have no idea how much more power the e-heads will make over the 6x-4’s with that cam(or a very similar hydraulic roller). Any thoughts on power and reliability of a 4.25 versus 4.5 stroke? This will be road raced and street driven with a 6-speed.
why do you want compression that low for aluminum heads?

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Old 10-02-2021, 05:06 PM
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Yes, I would like to keep the compression low for a couple of reasons, it’s a Pro-Touring build that will be street driven and road raced. It’s hot in Texas and it will heat soak after running hard at a road course(even with as good a cooling system as possible). I’ll also open road race and averaging 130-135( depending on what class I enter) really taxes an engine going 53 miles(and 53 back) The second reason is the next step; a turbo system. With lower compression it will be less of a hurdle than exceeding 10:1. This ethanol blend 93-octane is not very good. On my 462 with 6X-8 heads I have to “spike” the fuel with Boostane to ensure it doesn’t ping in the summer.

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Old 10-02-2021, 05:12 PM
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ok just curious. i was going to say, "unless you plan to turbo it" but didnt think that was in your plans.

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Old 10-02-2021, 06:34 PM
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Default Heads/Stroke

Any thoughts on power and reliability of a 4.25 versus 4.5 stroke?

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Old 10-02-2021, 06:53 PM
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A 4.5” crank in a factory block would scare me for endurance purposes depending on how many races take place before you get to tare it down to inspect it.
With a turbo the 4.250” crank will make more then enough torque and HP and lessen loading by a worthy amount!

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Old 10-02-2021, 10:38 PM
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Are these typical 20 minute race sessions Randy?

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Old 10-03-2021, 12:35 AM
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Tom, yes normal 20 minute sessions on 1.5-3.0 mile road courses but I’ll open road race at least once yearly. If I enter a 130-135 mph average class with a tech speed of 168 each leg of the course would also be around 20 minutes to go 55 miles.

I don’t have a turbo now but with the supercharger out of the picture I’m talking to the chassis shop about a single G42 and limiting boost to prevent the YY 455 block from splitting. I’ll probably go NA and just save to build the turbo on a aftermarket aluminum block.

I have to get the cylinder heads figured out and a stock height manifold for multiport injection to go under the shaker. I’d love to go with a Motec ECU but will likely go Holley HP.

The cage is done and the 3-link is waiting for the CNC drawings to come back as parts. It’s a full floater 9-inch with a MillerBuilt kit so I can run C7 hubs and C6 Z51 brakes.. The coil overs are JRI. Front suspension is SpeedTech with spindles using C6 hubs, JRI coil overs and a custom splined sway bar. Of course it’s a Magnum 6 speed.

The shop is run by Mike DuSold; the same guy who’s ‘67 Camaro with a TT LS427 has two Optima Championships and 6-7 LS Fest wins. He was running compound turbos at Pikes Peak this year but also has a tradition TT setup. He fabbed both systems. Good thing that Garret is a sponsor. The compound setup put out over 1350 RWHP. It’s been a month now so it could be the same compound with a G42 and G45 or more likely twin G42’s as the back pressure from the smaller turbo(1st turbo) limited the G45’s potential. Maybe thats the next frontier for OEM’s, it’s the ECU’s capability not the Engineers limiting turbo output.

  #30  
Old 10-03-2021, 08:55 AM
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PM to you Randy
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  #31  
Old 10-03-2021, 12:34 PM
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Replied Tom; thanks for the assistance.

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Old 10-07-2021, 10:43 PM
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Hey Randy, I would dish the piston and get the compression where you want, and keep a good quench. Win win situation.

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  #33  
Old 10-10-2021, 01:36 AM
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Quote:
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I have a set of the original design Edelbrock heads with 72cc chambers. Is it possible to enlarge the combustion chamber to 87, 93 or 100 cc’s. If so, what vendor does the work and what’s the approximate cost.

The dilemma I face is that even with new 87cc E-heads I need a bigger combustion chamber.

I’m currently running 6X-4 heads with 93cc chambers that have been flowed to 257cc and yield 9:65:1 compression.

I’d like less compression and greater flow to support a growth in CI from 468 to something larger.

Thanks for your assistance.

I've got a set of 87cc eddy's that I would trade for the 72cc ?

GT

  #34  
Old 10-12-2021, 05:13 PM
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BLUEGHOST, Are your heads new or used?

Tom V.

I will have to visit Gilmore's at some point.

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  #35  
Old 10-13-2021, 02:06 AM
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Quote:
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BLUEGHOST, Are your heads new or used?

Tom V.

I will have to visit Gilmore's at some point.
They are used. I don't think they have been run very much at all.
There off a motor that spun a rod bearing. Don't want to sell out rite
but would trade for smaller chamber.

GT.

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