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-   -   427 BBC pistons closed chamber ideas or? (https://classracer.com/classforum/showthread.php?t=89202)

sean1970ss 03-15-2025 06:45 PM

Re: 427 BBC pistons closed chamber ideas or?
 
Quote:

Originally Posted by Alan Roehrich (Post 710607)
So you need a solid 750-770HP. To be honest, that will not be easy with a 427, You're going to need a 288/298/108 or so cam and at least an 850 carburetor, and that assumes a good intake and heads. Rod length will not make a difference, you'll need about 12.25:1 compression. You're going to end up with what amounts to an average Super Stock engine, but you can use a better carburetor and get there easier. You could use any good shelf stock closed chamber 427 piston. Should be able to get one from Wiseco or JE, for sure.

I found one of my cams but the duration is over 300 .748 .748 112 cn for 250 shot of NOS. I looked in wiseco they have a nice set 4.310 bore. I can use any type of manifold and carb or tunnel ram. Going to scan the cards see what you think.

Thank you very much this is just a build I have always wanted to do for the heck of it. Slick Rick is doing my 291 heads,

Alan Roehrich 03-15-2025 07:10 PM

Re: 427 BBC pistons closed chamber ideas or?
 
Quote:

Originally Posted by sean1970ss (Post 710612)
I found one of my cams but the duration is over 300 .748 .748 112 cn for 250 shot of NOS. I looked in wiseco they have a nice set 4.310 bore. I can use any type of manifold and carb or tunnel ram. Going to scan the cards see what you think.

Thank you very much this is just a build I have always wanted to do for the heck of it. Slick Rick is doing my 291 heads,


Yep, the Wiseco stuff is nice. Vic Ellenger can get you a nice package, Total Seal rings and Trend wrist pins.


That cam isn't what you want. Way too much duration, not enough lift. You're going to want to be in the 0.850" range on lift, and 288/296/108-110 on duration, you need a custom for what you're doing. A good tall single plane single 4V intake will do fine. I'd use a big 4150, maybe a 1050 with annular discharge boosters, talk to Trevor Wiggins at Get'Em Garage.


You're going to want T&D or Jesel rockers, 1.75:1, or maybe 1.8:!, depending on the cam, and I'd use Ferrea hollow stem valves, the Comp 1.560" dual spring and tool steel retainer, they have some of those that are lighter than a triple spring with titanium retainers, and they're a better spring, higher quality material and finishing.

sean1970ss 03-16-2025 03:03 PM

Re: 427 BBC pistons closed chamber ideas or?
 
Quote:

Originally Posted by Alan Roehrich (Post 710613)
Yep, the Wiseco stuff is nice. Vic Ellenger can get you a nice package, Total Seal rings and Trend wrist pins.


That cam isn't what you want. Way too much duration, not enough lift. You're going to want to be in the 0.850" range on lift, and 288/296/108-110 on duration, you need a custom for what you're doing. A good tall single plane single 4V intake will do fine. I'd use a big 4150, maybe a 1050 with annular discharge boosters, talk to Trevor Wiggins at Get'Em Garage.


You're going to want T&D or Jesel rockers, 1.75:1, or maybe 1.8:!, depending on the cam, and I'd use Ferrea hollow stem valves, the Comp 1.560" dual spring and tool steel retainer, they have some of those that are lighter than a triple spring with titanium retainers, and they're a better spring, higher quality material and finishing.

Alan Thank you very much!!! Few questions Would you go 55mm and a 904 lifter? What size push rods? rods? Again Thank you so much sir. Sean

Alan Roehrich 03-16-2025 07:17 PM

Re: 427 BBC pistons closed chamber ideas or?
 
Quote:

Originally Posted by sean1970ss (Post 710627)
Alan Thank you very much!!! Few questions Would you go 55mm and a 904 lifter? What size push rods? rods? Again Thank you so much sir. Sean


I would absolutely go with 0.904" lifters, and if you can get 7/16"x0.165" wall pushrods, that's the way to go,sometimes dual taper will fit where straight diameter won't. If I were going to go for a bigger core, I'd go 54MM babbit bearing.

Jim Hawkins 03-24-2025 12:54 AM

Re: 427 BBC pistons closed chamber ideas or?
 
I have what you need.

420" BBC modified motor built in 1989.
4.31x3.60
Alum. rods, crower crank, light pistons, bowtie block, jesel belt, alum. bowtie heads, titanium valves, crane rockers, cast single and 2x4 manifolds.

9.60 at 3350# with a powerglide.
8000+ rpm!
1989 mile high nationals winner.
Awesome nostalgia motor with a stick.

You could not build your 427 for what you could buy this for.


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