more carburator on 18 degree 406 cui sbc

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hjallle123
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more carburator on 18 degree 406 cui sbc

Post by hjallle123 » Mon Jan 15, 2018 8:47 pm

Hi
I have a 18 degree smallblock with a hogan sheetmetal intake with 2 demon 750 cfm with 850cfm baseplate (just find that out)

the heads are brodix 18C heads weldtech cncported 2.18 1.625 titanium valves jesel 1.6 int 1.55 exh
flow 352 intake 700 lift 245 exh ,700 lift

cam is 114 lobe sep 110 inteke centerline

@0.50 282 in 294 exh dur ( yes the cam is about 10 degees wrong )
765 lift int 735 lift exh

( yes have degree the cam )

i did dyno tested the engine and it was making 768 horsepower on 7500 rpm
messured one carb on dyno it was flowing 495 at wot
so the engine was taking about 990 cfm

i was thinking if i am ported the heads with more flow to about 375-380 cfm on intake 265 cfm exh
changing cam with the new ported heads

can dual 1050 dominator carburators suport this

thinking.. with 0.5 vacuum the 2 dominators will flow about 1212 cfm with the sheetmetal intake

it dosnt mather if it will rev about 8000-8500 rpm

Thanks

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Re: more carburator on 18 degree 406 cui sbc

Post by swampbuggy » Mon Jan 15, 2018 9:13 pm

How many cubes ??? #-o

hjallle123
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Re: more carburator on 18 degree 406 cui sbc

Post by hjallle123 » Mon Jan 15, 2018 9:25 pm

406 cui

4.125 borr 3.80 stroke

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Re: more carburator on 18 degree 406 cui sbc

Post by MadBill » Mon Jan 15, 2018 9:28 pm

As per the thread title... :)
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

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Re: more carburator on 18 degree 406 cui sbc

Post by swampbuggy » Mon Jan 15, 2018 10:36 pm

Bud, i think you already have plenty of carburetor function, JMO, Mark H.

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Re: more carburator on 18 degree 406 cui sbc

Post by fdicrasto » Mon Jan 15, 2018 10:42 pm

The 4.125" bore is a bit tight for the 2.180" intake valve. Lsa too wide imo but not bad on hp.

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Re: more carburator on 18 degree 406 cui sbc

Post by NormS » Tue Jan 16, 2018 8:38 am

Modified 850 Holleys, flowing 1130 CFM, each would give you Dominator level air flow, but with higher mixture velocity than Dominators. Even with improved heads and possible improvement on your intake and cam, this would feed whatever HP your 406 will make. I built a set of these for a Ford 520, and that engine is making 1000HP .
Competition Fuel Systems Vassar, MI. www.compfuelsystems.com 520-241-2787

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Re: more carburator on 18 degree 406 cui sbc

Post by Rick360 » Tue Jan 16, 2018 9:07 am

Your carb size is definitely NOT holding you back at that HP level.

Rick

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Re: more carburator on 18 degree 406 cui sbc

Post by hjallle123 » Tue Jan 16, 2018 5:29 pm

thanks

what is your suggestion to make this to go over 800 horsepower :)

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Re: more carburator on 18 degree 406 cui sbc

Post by NormS » Tue Jan 16, 2018 6:16 pm

Those 750's you have can be modified to flow well over 900 cfm each. That would be enough to handle the power you're looking for.
Competition Fuel Systems Vassar, MI. www.compfuelsystems.com 520-241-2787

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Re: more carburator on 18 degree 406 cui sbc

Post by F-BIRD'88 » Tue Jan 16, 2018 6:41 pm

Be willing to play with the plenum volume and carb height to optimize for the bigger carbs to be best.

Do not relate carb size rating to what is the most powerfull carbs , especially on a tunnel ram..

Buddy did a very similar brodix 18x 406 sbc years ago when they first came out.
Your cam is not too big.

The only way to know for sure is to try the carbs and dyno it.

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Re: more carburator on 18 degree 406 cui sbc

Post by steve316 » Wed Jan 17, 2018 2:59 pm

your is too big; 276@ .050 is plenty. Too big a cam will cost you more HP than one that is too small.

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Re: more carburator on 18 degree 406 cui sbc

Post by bigjoe1 » Wed Jan 17, 2018 3:29 pm

I do NOT agree that his cam is too big-- I run much bigger cams than that, and I make much more horsepower at a higher peaking RPM




JOE SHERMAN RACING

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Re: more carburator on 18 degree 406 cui sbc

Post by hjallle123 » Wed Jan 17, 2018 3:34 pm

what do you suggest joe to make moore power on this engine

thanks

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Re: more carburator on 18 degree 406 cui sbc

Post by hjallle123 » Wed Jan 17, 2018 3:35 pm

f-bird this is not brodix x heads its c heads

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