SBC 4/7 swap headers
 

What header designand size would be best for a SBC 421?

10.5 Compression AFR 235 heads,Demon 1050 carb, Edelbrock Fully Ported Super Victor, 675/645 278/284@50 106ICL 110 lobe sep. 4/7 firing order swap.
Need headers for drag use.

2" to 2 1/8" step headers with 4" collector, nothing smaller than 2" for sure.

JMO

Zip.

Going into a 78 C10 Blazer.
No fenderwells. Build headers first then put fenderwells
back or actually cut them to fit.

Re: SBC 4/7 swap headers
 

Are your heads spread port exhaust?

Yes it is a speadport exhaust.

1 7/8 to 2 inch, or just 1 7/8
You need more compression.

I'm limited to 91 octane and a dish piston by rules.
I wish I could have more compression.
I have to run a 30'mile street test.
I have that taken care by a dual fan and dual radiator setup.

what kind of event are you runnin', Anyway ? :shock: :shock:

Ventura County Street Outlaw.
Up to 440ci displacement.
Limited to only smallblocks with 23 degree heads(On Chevy's)
Single Carb only unlimited induction.
Chevy's 23 degree heads Unlimited Modifications.
Limited to dish piston and 91 octane pump gas.
Unlimited transmission and unlimited rear end.
Unlimited Cooling.
Unlimited tire.
No power adders.
In the future I'll change classes and run 14:1 on Alky.
Dual 950 RS Demons with Hogan Sheetmetal intake.
Top it off with a Dual shot Fogger. 150 at the gate and another
200 shot. I'm crazy I'll still drive it then on the street too.

i would change the cam because it just aint right!! I would use a 2/3 4/7 swap cam with 108 Ic/l 112 lob sep 625 i lift with a 1.6 rocker adding .040 to that number the 656 exhaust and 1.5 rocker on that have the duration at 284 int 282ex I would give that a look good luck with your motor joe g 8)

ive been racin and buildin cars for 40 yrs and i still cant see how in the hell a 4/7 firing order is going to improve anything. things look good on paper but ive not seen any proof.

Outlaw i agree but there is one thing it dose help is crossfire as 5/7 fire wright after each other and the 4/7 separates the two. I have heard some say that there is power to be gained with 2/3 4/7 swap but dont know about just 4/7.

The 4/7 swap is to help with fuel air seperation for #2 cyl. When the car is moving forward and everything in the intake is going to the left rear for 5&7 then has to change and go to the right front.It does seperate 5&7 firing but it puts 2&4 together.I don't know if any one will get anything from the way I said that or not.Bill.

Sometimes my dad would call me simple.Bill.

DD chevys rule and mopars drule and fords are just another product of mopars so whats left :lol: :lol: :lol: :lol:

Well, I AM a member of the Old Droolers Car Club of Emmett,Idaho..... 8) 8) 8) "We be coolin' and droolin'"

well boys ive been a sbc fan my whole life. built some really bad ass engines. but a few yrs ago i got to really reading up on facts about the chevys ford mopar cars of the 60s and 70s. quess what i now own 19 engines and almost all are big block fords. 429, 460s with a few 390s for fun. and a extra 352 just in case myy dd goes south.as far as hp goes chevy didnt even get close to what mopar was doing. and ford was right there in the front also. i still love my chevys but i gotta give credit where its due and the other 2 are really the ones up front. just not as popular.

That is very true and was just having some fun with DD. I was surprised when roadkill posted about 302 boss heads i had forgot all about the left and right.

Truck motors rule . . Doesn't matter whether they're Ford or Chevy . .

Heh, heh . . . .

...or a 440 wedge....... :D

Why build a Chevy? Because that's the only way to go fast.
Just some of the guys that put Chevy's in Fords.
And especially SBC's to replace SB Mopars!!!!!
If it's not a Chevy or a Hemi it's a problem.

you build sbc because its cheap hp. thats the only real reason. ive been at this for 40 yrs.and ive never seen a stock sbc or bbc that couls hang with a same yr 440.or even fords old 406/ 4 speed combo.i have a 383 chev in a 53 ranchwagon. its fast but it could hang with my wifes chrysler 300 hemi.

$8754.23 ain't nothing cheap about this build.
You get what you pay for. 8)

well with todays dollars it is cheap.i spent almost 8000. just 4 yrs ago on a street motor and i did it all but the machine work.

Yup today money isn't worth shit compared to just five years ago.