What cam and CR are you running with 8 stacks?

I’m currently in the engine building stage and it’s coming to piston ordering time.
Because of this I’d like to know what static compression ratio, cams and fuel you guys with 8 stacks are running to give me an idea of what I can actually work with on the street. Ideally for the cI’d like to know your duration, lift, LSA and when the inlet valve closes after BDC or whatever info you may have!
If you can specify whether you’re webers or efi that would be great too!

I know it’s the dynamic CR and cam events that affects the real world, if you know that for your build too even better otherwise I’ll work it out myself from your specs.

My build:
402ci 9.2”
3.75 Molnar Crank
6” Lunati signature I beams
Will be custom Ross pistons
225 TEA High ports or Profilers
EFI 8 stack, sequential injection, COP and knock sensing.
Jesel belt drive
Dry sump

Many thanks,
Chris
 
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Neil

Supporter
Chris, why not just call Comp cams and ask for their recommendation? Billy Godbold knows more about cams than anyone on this forum.
 
Chris, why not just call Comp cams and ask for their recommendation? Billy Godbold knows more about cams than anyone on this forum.

I’ve spoken with Bullet and I have a general cam guideline but was interested in seeing what others are running. Not looking for recommendations just for what people on here have.
 
I told Compcams my engine specs including the Rhoads lifters I was going to use and they grinded me a custom cam for my street & emmision regulation needs.
It might be controversial but I like Rhoads lifters on most of my engine builds.
 

Rick

Supporter
I just sent my 427 sbf to Ron Shaver racing for a rebuild. I am going to 8 stack injection and will report once I know his cam selection, it will be a few weeks till I hear. Build goals are 600hp on pump gas.
 
I’ve spoken with Bullet and I have a general cam guideline but was interested in seeing what others are running. Not looking for recommendations just for what people on here have.
Hello,
Have Weber’s on a custom Intake 48idfs.
427 Windsor Ford x303 cam has really good specs for Weber’s.
Runs great 5-7000 ft above sea level.
 

Dwight

RCR GT 40 Gulf Livery 347 Eight Stack injection
which EFI system will you be using?

I have Borla Eight Stack.

I called their tec line a couple of months ago and told him I had a sbf 347 in a GT40 with G-50 transaxle. He recommended Comp Cam 35-518-8.
I have run this cam in another motor years ago. Fuel injected 354 (347 with more stroke). It dyno a little over 400 tq and hp to the rear wheels several times. Great cam. It produced 350 ft lbs of tq at 2200 rpms. Like I said "great street cam"
 
which EFI system will you be using?

I have Borla Eight Stack.

I called their tec line a couple of months ago and told him I had a sbf 347 in a GT40 with G-50 transaxle. He recommended Comp Cam 35-518-8.
I have run this cam in another motor years ago. Fuel injected 354 (347 with more stroke). It dyno a little over 400 tq and hp to the rear wheels several times. Great cam. It produced 350 ft lbs of tq at 2200 rpms. Like I said "great street cam"

Either a jim inglese/borla weber look efi or the 55mm borla EFI - currently working out what size ITB is needed for my CI and rev range - i prefer the look of the weber but concerned that 48mm TB's may not quite be sufficient enough for 400CI, 340cfm heads and 7500+rpm not that i necessarily need to be making more power past 7k but i dont want it to choke out and not rev higher.

Sounds like that cam worked well for you, 350ftlbs is great for 2200rpm!
 

Dwight

RCR GT 40 Gulf Livery 347 Eight Stack injection
fuel system (22).JPG
 

Terry Oxandale

Skinny Man
Can't recall or find what I used to calc for allowed HP with 48mm ITBs, but thinking it was 550-570. Mine start out at 58mm at the top of the ITB (where the tubes attach), and smoothly reduces to 48MM by the time it gets down to the throttle blade. My goal was 500 HP, so I knew I'd be under the max based on the calcs. My interpretation of information I've read is that the taper and the stacks (they were cut to a specific length as well for max tune at 6K rpm) are helpful as well.
 
Is quite a bit of science to work out things like that. All depends on how you want to use the engine.
This is basic generaliststuff that I’ve found online before. The second is a calculation using my bore and stroke (3.750 and 4.126)

9D82BEDE-9981-4853-B78A-63D50E265CAE.jpeg

I have seen people staying wildly different figures for the above also.


C42D108C-A6F1-400D-A739-1C211CBFEC5C.jpeg
 
Chris, see the attachment. I went EFI. I have attached the COMP CAM specs. Been very happy with the motor and over 12,000 miles. Dry sump, solid roller with Jessel Shaft Mounted Rockers. PM me if you have any other questions. With the Eightstack system we were getting lean on the far side. We then put a Y in the feed and spit to each side with the return at the back and that corrected the problem, at least in my case.
 

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