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So I’m just about ready to buy a new set of aluminum vortec heads, but I just stumbled across a site that said my 113’s are just as good on the flow bench. I though that good flow numbers and better ports where the vortec’s main selling point. So I’m a little confused.
The motor is a stock bottom end, and will go with a LT4 hotcam and a TPIS miniram. What do you guys thnk?
I don't know the flow numbers on the Vortex heads but comparing those numbers is the way to make your decision.
Remember that our #113s brought an extra 10chp over the 128s and a good porting job will add say another 30chp.
How much power will the Vortex add over the stock #113s using similar intake setup??
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A stock 350 bottom end @ 6000 rpm only needs ~230 cfm per cylinder.
The 113's in stock form get about 195cfm. Good porting will get you close - depending on the porter. TPiS claims 250+cfm after porting. I haven't seen real-world numbers to support.
I don't know the #'s for the Vortecs but hear they are good for mild-motors and efficiency. Any head you look at needs to hit these modest numbers.
If you want to change the short-block some day, that might change your considerations to a better head.
The heads that GM touts as the "Alum Vortec" heads are infact the GM "Fast Burn" heads.
The only thing they have in common with the cast iron Vortec's is the intake bolt pattern. They use LT4 valve train parts (hollow valves, springs, retainers). They are vastly superior OTB than the stock L98 113 castings. The 113's can be ported to perform as well as the fast burn heads, but once you spend the same amount of $$ on the fast burns... they are vastly superoir again.
Drawbacks to the Fast Burn heads include the intake bolt pattern, which require an expensive Vortec specific lower TPI intake. Then there is the fact that for the money there are numerous aftermarket heads that will out perform them and don't require anything special. Brodix KI180/200, Dart, World ect.
Will
As cuisinartvette stated its not about the max flow number, its the 100-600 lift figures, or low lift,mid, and high lift numbers. I would choose better heads.
awhile back i ported a set of 113s & managed 228@.500 on the intake and 196@.500 on the exhaust with mid lift moving up similar percentages. with a miniram and 503 cam it sent a 6spd car to 12.7@110mph. the chambers are dated on a 113 though. if you could get a vortech style MR the edelbrock etec 170cc head is a very good choice.
awhile back i ported a set of 113s & managed 228@.500 on the intake and 196@.500 on the exhaust with mid lift moving up similar percentages. with a miniram and 503 cam it sent a 6spd car to 12.7@110mph. the chambers are dated on a 113 though. if you could get a vortech style MR the edelbrock etec 170cc head is a very good choice.
i have pics but none of them are really going to show you where the work was done. the short turn radius in the intake is thick enough that you can smooth and reduce the turn angle slightly giving it a straighter shot at the runner. use cartrage sanding rolls in the bowls and short turn. bits could be used at first to match the intake to the manifold. a good valve that's necked down helps. manly race-flo in the stock sizes were what i used. a good 3 angle job is also needed. radius the metal holding the guide...this is a bizatch to do but the aluminum holding the guide is thick and somewhat intrusive. smooth the intake runners & do the above mentioned. if you haven't ported before do watch the standard abrasives video first. in the chamber your big goal is to get some of the overhang gone, like back by the spark plug where the valves sit. polish the metal up & use sanding rolls back there to open up the area. with a good valve job and 4-5hrs spent on each head you could achieve similar. i sold those heads awhile ago & replaced them with a pro action 180cc casting. heads suck out of the box assembled but they can perform if a machine shop specs the guides and you use a decent valve. the same car now goes 12.4@113 and may have more with a good tune. in my experience edelbrock is one of the few heads i would run right out of the box and not think twice about it. AFR's cnc'd spec to build stuff is also supose to be really good but most likely out of your price range based on the heads you are considering.
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Originally Posted by racebum
...In my experience edelbrock is one of the few heads i would run right out of the box and not think twice about it.
Based on your times, it sounds like you did a good job with your porting. Well done!
Since Edelbrock's aren't listed as polished (intake/exhaust/or bowls) and since their flow numbers would decrease somewhat after head-milling (to 58cc), what fancy's you about their out-of-the-box performance? Why didn't you pick them for a replacement?
I'm not challenging their value -- just asking for elaboration.
113# about 199....Vortec about 240. Vortecs were designed along with the LT1 heads, and flow very well, especially in the low-lift areas. They need some machineing mods for higher performance use, but for milder cammed motors they're good, stock. There is that pesky Intake Manifold problem.
GREGGPENN...milling the heads doesn't generally have much effect on the flow.
Based on your times, it sounds like you did a good job with your porting. Well done!
Since Edelbrock's aren't listed as polished (intake/exhaust/or bowls) and since their flow numbers would decrease somewhat after head-milling (to 58cc), what fancy's you about their out-of-the-box performance? Why didn't you pick them for a replacement?
I'm not challenging their value -- just asking for elaboration.
gp
this is a very good question. what i've found with edelbrock heads after my own previously; and others that still have them; is the build quality. guides are spec'd right and the valve job lasts. springs are of good quality and they really do work to 6500rpm. my own aftermarket heads, the pro actions are half-ask assembled out of the box. these heads had something like 3 bad guides that would have caused oil burning when they were new. this isn't uncommon with aftermarket heads from what i have gathered keeping my ears open. price is the other thing i'm considering when i think about your goals. edelbrock is priced not too far above a complete rebuild of the 113. you also would avoid the porting time. the etec 170 is the head i would chose since the performer and performer rpm are dated designs. if i remember right even the vortec has a modernized combustion chamber. also, exhaust flow is MUCH easier to pick up when porting than intake. it's also faster to port.
ZZ4 v Fastburn 385 crate carb engines
Same block , same cam
ZZ4 w /113 heads ;355Hp / 405 Tq @10:1
385 w /Fastburn heads ;385Hp / 385 Tq. @ 9.6:1
Makes 435Hp w /Hotcam. http://sallee-chevrolet.com/ChevySma...leeZZ430HP.cfm
The cast L31 Vortec heads #12558060; 170cc / 64cc Chambers / 1.94-1.5 are not the aluminum vortec heads (Fastburn ) that the OP mentioned
From another site,
"The Fast Burn heads feature a raised intake port that measures 210cc. Normally, we'd say that 210cc is kinda big for the street, but GMPP did their homework on this head and combined it with smaller than normal valves (2.00 intake, 1.55 exhaust) and an efficient 62cc chamber. The hollow-stem intake valves and sodium-filled exhaust valves are incorporated to reduce mass which allows for better valve control at higher rpm."