Porting sbc ramhorns

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Porting sbc ramhorns

Postby BOOT » Tue Sep 12, 2017 10:22 pm

Ok gonna use a set of new cheap($75 for the pair) dorman sbc 2.5" ramhorns. I already basically started to clean one up just to see how working the grinders in them is and I can tell you can't really do a ton.

NOT an option
-extrude honing
-buying castheads.com/Brzezinski manifolds
-headers

So basically gonna clean them up(casting flash ie), grind back the internal bolt bosses some, open up the ports to just a bit larger than the head for a step and idk but I've read grind down the reversion bumps?
I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!

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Re: Porting sbc ramhorns

Postby bigjoe1 » Tue Sep 12, 2017 10:49 pm

Do not spend too much time or money to do this--- VERY LOW RERWARDS-- You will never know the difference





JOE SHERMAN RACING

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Re: Porting sbc ramhorns

Postby BOOT » Tue Sep 12, 2017 11:12 pm

I already have supplies I use for heads/intakes or w/e, if I spend a couple days of my free time prepping a part it's always worth it to me. Fixing the port mismatch is the biggest gain I'd bet.

I was thinking the SSR up on the outer ports kinda like heads prob would benefit from widening.
I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!

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Re: Porting sbc ramhorns

Postby pdq67 » Tue Sep 12, 2017 11:30 pm

Guys,

How much of an upgrade will the rams-horns be when compared to logs and how much of a downgrade will they be vs a cheap pair of 1-5/8" dia., 4-tube, long tube headers? Or for that matter, a cheap pair of, 4-tube "shorties"?

And I have a pair of new rams-horns just to have is all. A left and a right, both with alt. mounts so I can choose what side I want to put my alt. on.

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Re: Porting sbc ramhorns

Postby BOOT » Wed Sep 13, 2017 2:32 am

Far as headers vs ramhorns it depends on the displacement, cam and exhaust used. I've seen test with next to no losses and other with a lot, google "ramhorn dyno". I just bought two of the same because I'm gonna cut the brackets off.
I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!

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Re: Porting sbc ramhorns

Postby mag2555 » Wed Sep 13, 2017 5:40 am

Yes, very small returns for time spent on these!
Make the transitions as smooth as you can and polish out any casting ruffness and call it done!

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Re: Porting sbc ramhorns

Postby Carnut1 » Wed Sep 13, 2017 5:58 am

I would spend some time on them and mill the bosses out. Check the csa and if you can bring the whole path up in csa a bit it won't hurt. I like to oversize the entrance a bit on these for a anti reversion lip. How big a cam, displacement and rpm? 355 with a mild cam and 6000 rpm these will do fine. Thanks, Charlie

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Re: Porting sbc ramhorns

Postby ZEOHSIX » Wed Sep 13, 2017 6:35 am

I'm not sure about the China re-pops but, the OEM Chevy castings sometimes have large obstructions in them that will definatley cost lots of power. I wasted $100 worth of extended shank carbide burrs on a pair of Vette 2.5" manifolds once in my life.....running mid 12's at the drags and lifting the hood to have people freek out at seeing stock manifolds made it all worth while.....dyno testing.....swapping for a set of Hooker 1.75" Super Comps made 20-35HP improvement across the entire RPM range and TONS of improvement on low RPM torque.....

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Re: Porting sbc ramhorns

Postby cuisinartvette » Wed Sep 13, 2017 10:32 am

x2 the bosses are obstructions, with joe

spend crazy amounts of time on a guys ramshorns to the eye it should move more....maybe on a bench somewhere but sotp it did absolutely zip...zero
if you want to do it knowing somewhere you went after every last bit sure wont hurt anything.

Lots of mods that in theory may work but dont when its all put together...see what youre saying though. Dont breathe that crap of get it in your eyes!


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