302GT_killer

which of these heads would be best? im looking for 400 hp/ 400 tq and the cam will be a comp with about .510 lift with 2800 stall and 3.73s. i want all the power in by 5800 rpm

steve8586iroc

Look in the new chevy high perfomance. They test the 180AFR heads with some impressive results.

Steve

302GT_killer

yeah i got that in the mail the other day and now im rethinking- i was going to go with the 195s but then they said a good engine builder will always say to go with the smaller port heads. i dont think i want to go with as small as 180 cc if im spending $1500 so im debating if i should go with the 190 or 195 cc

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soon that white 5.0 lx at school will get a good waxing from a nasty 355 RS...heheheheheh

Grim Reaper

Yes, Super Chevy said that "Given the same flow, go with the smaller runner..". And there is a lot of truth to this. It increases velocity which helps with low end torque and engine responsiveness, while not penalizing top end flow (to a point). But if you want all out top end performance and don't care about low end performance, then you will want a larger runner.

But the one thing they don't mention is, that the head's runner must also match the runner size of your intake manifold. If your manifold's intake runner is 210cc and your head has 180cc runners, then you are going to destroy the flow when the air hits the smaller intake. To correct this, you would need a smaller intake runner.

Changing your intake is fine for a carb setup. But if you bought a Miniram, you don't want to spend another $895.00 on another version.

Bottom line, you want to match the head's runner to your manifold's. If you want a nice street motor, a smaller runner promotes low-end torque. If you want more of a "strip" car and not really concerned about low end torque, then you'll want a larger runner. Just make sure you intake manifold matches or you'll be sadly disappointed and not get the results you were hoping for.

Paul Riccioli Jr

iTrader: (1)

I would suggest the 190 heads. I've heard that the 195's have problems with the seal between them and the intake manifold. As far the the 180's, why go with something that small when the 190's are about the same price?

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Riccioli Performance Motorworks

--RPM Racing--

-Currently building first ever engine. 383 with Super Ram plenum and runners, Edelbrock lower intake, Bosch 24# injectors, AFR 190 heads, MSD ignition.
-Will be installing Baer Brakes
-Will be installing full Spohn suspension in rear
-Art Carr 700R4 trans??


Attention Everyone!!! I will be changing my name on the message boards to HardcoreZ28 sometime in the near future. Just wanted to let everyone know.

88IROCs

I don't see a significant difference in flow between the 190 and the 180(based on published flow data). Yes, the 190 has superior intake flow at all lift points, but at low and medium rpms this usually leads to a decrease in velocity(cylinder filling) and transition(responsiveness). Based on the other components you mentioned and the intended max rpm, I would assume you are not building an all out race motor. Therefore, low and medium speed operation should weigh heavily in your consideration.

Another factor to consider is the exhaust/intake relationship. While the 190's have better intake flow, the 180's have much better E/I ratios(83 - 85% vs 75 - 77%). Remember - you have to get the burnt gases out, before you can put fresh air in. TPI engines seem to respond especially well to high E/I ratios, so this may be a factor to consider.

At any rate, either of these heads will outflow the cam you mention, and most intakes you would match to them(based on the criteria you mentioned). So neither oof these heads would seem to be the limiting factor in gaining all-out performance in your planned motor.

Good Luck.

[This message has been edited by 88IROCs (edited April 20, 2001).]

302GT_killer

thanks everyone- i think ill go with the 190s but one question-heat riser or no heat riser? my buddy said to get one since aluminum expands contracts but the catalog makes it look like an emissions piece-i am not an emissions state so i dont care but does the heat riser have anything to do with the EGR valve and should i get heads with or without a heat riser?

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soon that white 5.0 lx at school will get a good waxing from a nasty 355 RS...heheheheheh

Grim Reaper

If you have TPI, you want the L98 heads that have the EGR passage. "Heat riser" is for carb'd engines.

If you can keep your EGR, do it. It is your friend, not your enemy. The EGR is disabled when you stomp on it (and you can control at what %TPS it disabled). But an EGR helps you with your gas mileage by filling part of your cylinder with inert gas and makes the engine effectively have a smaller displacement. Why waste all that gas while you are cruising? You want you max power when you are at WOT, and the EGR is disabled at that point so it costs you nothing.

302GT_killer

my motor will be carbed-can i run an EGR with a carb or only with injection? i got one now on my TBI. so should i get the heat riser then?

89gta383

iTrader: (5)

Buy some of the L98 aluminum heads that are on the classifieds section, and get them fully ported. Same performance, almost half the price if you get them cheap. Same with the dart's.

Dan87IROC-Z

I've never heard of ported L98 heads being "equal" to AFRs or Darts or anything of that nature. There is some power in porting, but nothing like what you get with a set of new AFR heads.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

Soon to Come: 7.625" 10 Bolt with 3.42s and Accel TPI Intake Base

89gta383

iTrader: (5)

LPE uses L98 aluminum heads on most of their superram motors. With some port work, they will make the power that he is looking for.

302GT_killer

i appreciate the suggestions and like the idea that the AFR heads wont be the limiting factor. i dont think i could even use the L98 heads with a carb because of that EGR passage and id rather stay away from them since i know they have a definite limit. yeah they might work now but i plan on using them again someday on another motor to hit low 11s-right now im heading for consistent 12.8s and think the AFR 190s are a good investment, but i still need to know-heat riser or not??

302GT_killer

oh and the motors a 355 in case you may be wondering

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soon that white 5.0 lx at school will get a good waxing from a nasty 355 RS...heheheheheh

jaretz28

With a Chevy 355 and the specs you want, my friend built an engine out of a Chevy High Performance Magazine last year. They dynoed it and all in the mag. The engine was 10:1 with a 750 CFM carb, Edelbrock Perfromer RPM intake and 1 3/4 full length headers and a comp cams 280H cam. The AFR 190cc heads were used and it made power to 6,600 RPM if you want less RPM then go with an intake manifold that is in your range like an Edelbrock Performer( idle to 5,500 RPM) Oh, the engine made 426 HP and 415 lbs. - ft torque. Pretty impressive for a "little" 350.

BadSS

If you’re wanting something “out-of-the-box”,,, and you’re not just dead set on spending the bucks for the AFR heads you can save $400 or more by going with a set of Canfields ( www.jegs.com ). They “only” cost $1000,, and I can tell you from building engines using both the Canfield and the AFR heads (195’s) there is not much if any difference between their power output. The AFR has a little better I/E ratio,, but you can cure that to some extent by increasing the exhaust duration (split pattern cam),, which should not be a problem for you running a carb and 2800 stall.