Head flow / intake flow

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35regal

35regal

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:burnout:i been away for a while, now im back into it now that my cuda is running real strong. im curoius about cyl. head flow and how much it changes with different intakes. if anyone has any links to this subject please share. example - lets say your heads flow 290 cfm on the intake side, how much did it change by adding a rpm intake, or a dual plane , or my favorite tunnel-ram.
 
I can't speak to the numbers, but it sure sounds those heads would like a single plane? Maybe a Victor340?
 
29O intake flow,sorta cool. Throw the rest of the combination up,please.......
 
SORRY THE 290 is just a example. mine flow 277 @600 lift,eddy ported. MY curiosity is -you can have heads that flow 290 but after you add your intake pick your choice , dual-single plane or t-ram ,WHAT CHANGE DID IT MAKE TO THE HEAD FLOW #s?
 
my motor has been built for prob 2 years, but i have had several set backs-issues. trashed tranny, blown head gasket# 5 cyl- it was leaking for some time, i thought i just had a lot of crankcase pressure, so i spent some time trying to fix something that really wasnt the problem, i eventually i did the pan -ovac system, the latest issue i had was my ign. timing was jumping back and forthe at least 10 degrees. the fix was a bad pick-up in the msd dist. so for the moment i have gooten the bugs worked out. shes running really good, better than ever, the pick -up was prob bad since i installed in the new motor, it was a used dist.
 
Edelbrocks. Raised the roof .060,streamlined that obnoxious bolt hole relIeved. Time to learn.....
 
heres the build. fishy 68 assembled the motor, he does very nice work. .40 over 340 block , steel scat crank, scat rods, steel crank scraper, 8 qt pan milidon, mellings pump worked over by fishy. diamond pistons , 11.8 compression, eddy ported -stock valve . flows 277 at 600, 215 on the ex side, the cam is a ultra dyne solid mech cam, specs are 263 in 0.50 267.0.50 ex. lift with 1.6 is 637 in 651 ex with 1.6. rockers are prw stainless , i have had no problems with these rockers , but i did have to do some clearence work on them, they were on my 340 first.the intake is a eddy t-ram , port matched, i just swapped from 660 holley center squirters-e-85 to 2-750 holley vac secondary carbs -E-85 converted, with .180 downlegg boosters. i had 4.10s in it, im swapping to 3.91 with a fresh clutch type sure grip. tires are 28x13.50 et streets, vertor is a 9.5 in. flashes about 5000 rpm. 727 manual valve body . shes not a everyday driver . hoping to run it around 1 or 2 times a week. just finally got it insured. 3 inch ex. with dyno max muffs and 1 3/4 hookers. :burnout:
 
But his question is not answered.

IMO, the "Right" intake will allow the head to flow at its best while the wrong one will hinder flow lowering the heads CFM. To this end, you can not give your heads enuff air flow and flowing smoothly through an intake. That woe suggest I'm Ok with a large plenum T-ram on a stock engine. But I'm not. Though a good FI system would fix that issue as where a carb would probably have an issue or two.
 
Fi sounds expensive, heres a pic of the motor, still working on getting the compartment tiddied up.
 

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Carbs will never equal the ability of EFI (though the best efi out there now is direct injection, but you get the point). If you're going to use an NA motor either carb or efi will work but if going for a boosted app, EFI is the only way to go IMO but thats just me.
 
You're trying to get results for two seperate parts of the intake port. In terms of the port it runs from the carb's throttle plate to the valve seat. If you flowed the heads you can use those numbers to pick a camshaft, and use those numbers to estimate what the output "should" be with an intake that compliments them. Bu tin terms of empirical data points - you are screwed. Not too many shops flow intakes because it's a pain in the butt and those that do make claims that are hard to back up - dry airflow due to a steady suction is not the environment in which an intake works. Have you had the engine on a dyno? Not a chassis dyno - an engine dyno that has full data recording? You need to see the BSFCs and efficiency numbers to see if the intake is actually working for you or agaisnt you on your exact engine.
 
I've done some head flow testing with and without an intake bolted on. Head flowed around 275 w/o int 240 with a China man single plane and 260 IIRC with an untouched Eddy Super Victor. These were Brodix SPEC heads for a SB Chevy. Flow tested a set of Dart BB Chevy heads in the 400 cfm range, bolted on a sheet metal intake virtually no loss.
 
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