Chevy 305 Heads and Engines



Flow bench tests/numbers for 187 casting aka Swirlport

On this day of testing back in 06 I flowed 3heads, #1) a350 smogger with fresh v/v grind # 9889338, very similar to the 882casting, #2) aHO head # 14101081 used and cleaned up for testing, and #3) aTPI/TBI 14102187 with 3 angle v/v grind. Testing was corrected to 28” and doneover a 4”bore and a 300 cfm hard edge restrictor plate



First up the HO head.


Valve lift CFM@28" HO 305 int.

0.05............. 25.5

0.1............... 84.2

0.2............... 103.9

0.3 ...............149.2

0.4 ...............162

0.5................159

0.6 ...............159



350 smogger Flow #s similar to Dart SR


Valve Lift CFM @28' Smogger int.

0.05 ................21

0.1 ..................82.7

0.2 ..................108

0.3 ..................191

0.4 ..................192

0.5 ..................191

0.6



And finely The TPI/TBI



Valve Lift CFM @28" TBI int.

0.05 .................31.3

0.1 ...................88.4

0.2 ...................159.3

0.3 ...................192.6

0.4................... 233.3

0.5 ...................246

0.6................... 245.5



The TBI head with porting , bowl ported in a helixform enhancing cast form, opened up bowl roof.



Valve Lift CFM @28" TBI int.p

0.05 ................25

0.1.................. 88.4

0.2 ..................159.3

0.3..................192.6

0.4..................230

0.5..................248

0.6..................253

 

https://www.thirdgen.org/forums/tbi/...ted-193-s.html

 

Looks like an old member re-registered and posted up more of his drivel.

Whats the flow numbers? Power numbers? ANYTHING numbers? All I see is a lot of and no factual data and a glaring error of SBC history.

Gee thanks for registering here and posting this. So helpful.

 

lol

 

It's all relative though? Maybe to some one with a 305, it IS all that?

I remember when I thought my stock car was the shiznit, until I rode around in a 12 second car.

I'm not getting into none of you guys' cars anymore, not no way but nohow! I can't afford it. Especially not one with nitrous or a turbo. Never.

 

Here's your numbers...
https://www.thirdgen.org/forums/tb...ted-193-s.html (Garage Ported "193"s (Flow #s))

 

Hey petetinga,
Thanks for sharing your thoughts! In the spirit of "hot-rodding" and "turning a wrench" - I'll work on a set of heads that I have from a 1993 or 1994 5.7 - 4 bolt main engine. The last set of heads that I blueprinted were on a "30-over" 429 Cobra Jet engine... now that was FUN!!

 

Yea, thanks. The OP did not post any results to back up any of his banter. Waste of internet space.

 

But it's on the internet; it MUST be true !

 

There's a reason why Vortecs are popular.

 

Vortec are good but nobody ever talks about how air flow becomes unstable @ .500 and up lift, with porting they'll flow 250 cfm at .450 lift but it falls off after that piont because of instablaty.

 

vortec is the perfect street head because of it's low peak #s...... compare it to any afr head or whatever you consider the best and it's power under the curve for a factory power band is unmatched... It's all about most flow under the curve with the highest velocity. Just remember the smaller runner the higher velocity (yes this is an oversimplified view ,but tends to hold water to a point).....

No btw i'm not saying a vortec is the best head btw...... i'm just saying as a bolt on head especially for this era f-body it's pretty much your best pick.... Good swirl, high velocity, smaller runner. Works perfect with crappy gear ratios and stock converters as well as a 2 bolt main cast engine like most of us are running, also is a good addition to tpi/tbi combos in the instance that they aren't designed for massive camshaft combos.

it doesn't matter how great your heads are at peak flow, it's flow under the curve, unless your building a motor as a straight up race car or circle track so on (wider power curve thats higher under the curve will always win).

how often are your heads running over .500 lift....... on a stock application never since you are maxed out around .460.
anything over .500 is starting to get in to a little wilder territory.... Now when you are considering highly modified race cars, the peak #s maybe the most important depending on the rpm range you run in and what kind of gear ratios....

i'm just saying people shouldn't concentrate on peak flow #s so much..... It's the same thing with camshaft bigger is usually not better especially for the street.

also i do beleive your intake flow #s to be a little on the low side for a vortec btw.....

 

Ya ive read that about peak flow and under the curve info, If peak flow is .460 than ya you should run .510 lift or more so the valve spends some more time open at or around that optium ive wondered what that unstability dose above peak flow, i suspect in that short time frame its not that much of a problem.

 

My flowbeach isnt setup right now cause i moved (devorce eh) my datas in a box somewhere so i just go by memery for now,
one thing ive always wanted to do is build a rig to open and close the valve while im flowing the head, a variable speed motor, cut the lobes off some old cams that i have. im sure somebodys allready done this but ive never seen any info on the net.
I think it would be interesting to see what is happening in a more dynamic state.
I built a plexy glass carb adpter about 6" tall once it had 4 tubes i stuck it on a engine and fired it up to have a look at what was happening, basicly all you see is a fog, what i wasnt expecting is that the adaptor nearly shattered it formed cracks like mad, you see the vapor froze the plexy glass, vapor pulls a lot of heat. well anyway thats just some more of what did someone responding to this thread call it......Blah, blah, blah.

 

Wow ... Most useless **** I've never read

 

Also 4 years old. Time to let it die again.

 

Wow glad I never saw this post. I am still around, haven't gone a place.

 

Forum cops who quote the date as if it's relative to anything are gauging time by how long they've had there back door implants,

 

I would love to see data posted rather than just word of mouth. I will be doin a 305 build in the near future and plan to test some things. Considering stock 416 heads cam only type build, maybe L30 vortecs, or step up to a custom head around a 1.94-2.0" valve if i can fit it. 1.94 maybe all i will get in that small bore.

Just be nice to see what all the heads are doing for flow and power. I have some online resources for flow for various stock heads but still be nice to see others verify it

 

This post is fairly useless with no data to back up any claims. Useless threads should die quietly.

 

http://www.superchevy.com/technical/...d/viewall.html

Little article on tfs heads and cam on a 305. Was hoping to see alittle higher numbers than 362 hp but cam is smaller

 

Agreed ... I was hoping for closer to 400 .. I have these heads on the way to my house actually

 

I would like to see what the 268xfi would have done with a good short runner intake. I think the extra lift would have helped. But yes i was thinking 400 ish hp

 

Go check out my build thread " lo3 rebuild (HP Estimates)" u can search foogle n it'll pop Right up .... My cam will b .520/.528 lift w/1.6 rockers & 218 dur.

 

I,ll put some numbers up this week

 

Someone needs to put a good single plane intake, a large enough carb and some headers with 1 3/4" primaries on their 305 to see 400+ hp. My 9.3:1 312 in the vette running stock 906 vortec castings with 1.94/1.60 valves and 5 angle radius valve job as the only modifications is making atleast 380 hp based off my trap speeds. The car is not daily driven, has a 2,600 rpm converter and 3.07 gear and will boil the street tires completely off the car in 1st gear. Whoever said a single plane does not make torque is kidding themselves.

 

Flow bench tests/numbers for 187 casting aka Swirl port

On this day of testing back in 06 I flowed 3 heads, #1) a350 smogger with fresh v/v grind # 9889338, very similar to the 882 casting, #2) aHO head # 14101081 used and cleaned up for testing, and #3) a TPI/TBI 14102187 with 3 angle v/v grind. Testing was corrected to 28” and done over a 4”bore and a 300 cfm hard edge restrictor plate

First up the HO head.

Valve lift CFM @28" HO 305 int.
0.05............. 25.5
0.1............... 84.2
0.2............... 103.9
0.3 ...............149.2
0.4 ...............162
0.5................159
0.6 ...............159

350 smogger Flow #s similarto Dart SR

Valve Lift CFM @28' Smogger int.
0.05 ................21
0.1 ..................82.7
0.2 ..................108
0.3 ..................191
0.4 ..................192
0.5 ..................191
0.6

And finely The TPI/TBI

Valve Lift CFM @28" TBI int.
0.05 .................31.3
0.1 ...................88.4
0.2 ...................159.3
0.3 ...................192.6
0.4................... 233.3
0.5 ...................246
0.6................... 245.5

The TBI head with porting , bowl ported in a helix form enhancing cast form, opened up bowl roof.

Valve Lift CFM @28" TBI int.p
0.05 ................25
0.1.................. 88.4
0.2 ..................159.3
0.3.................. 192.6
0.4 ..................230
0.5.................. 248
0.6 ..................253

AS you can see the 187 casting flows some really decent numbers even giving the Vortec a run for it’s money!

 

I'm doing another 305 build now, a 310 for my 88 S10, A roller cam, swirl port, 9.75:1 compression carburetor setup, 308 gears and 700r4. I'm gona chassis dyno it when im done, good or bad i'll post the results here.

 

After porting what was the intake and exhaust runner volume? CC volume?

 

Dude everyone here knows the TBI swirl ports "187" only flow 140-150 CFM on the intake side why make up imaginary #'s ? And I have a set of ported 187's setting on the shelf ... And would prolly sell em for a little over scrap price ... If these flow numbers u posted
We're real everyone on the planet would want them seeing as u can get them for next to nothing ... And according To ur numbers these junk heads flow almost As much as trick flows super 23 175cc heads for 1200$

 

Looks like they get about 160cfm in stock form

https://www.thirdgen.org/forums/tbi/...heads-why.html

 

Yea my bad 165 intake 140 EXHAUST .... Which us nowhere even close to what this guy posted above ... 250cfm ? Seriously hahah yea right ... When u make 500 HP with these heads then ill believe those flow numbers which according to ur flow numbers these heads can support well over 500HP with the proper supporting mods

 

I got nearly 230 out of the intake side and over 200 out of the exhaust from my ported 193s. HotRod Magazines 4.3 buildup used TBI head that also flowed about 210 cfm intake and similar exhaust number.

 

Ok and he is claiming a stock 187 is flowing 245 with nothing but a seat cut

 

I don't know I didn't hog on them mostly cleaned up smoothed things out, small gain, 4 angle seat was all it needed, oh and also back cut and cut down vortec valves so I could run 0.500" lift

 

As big as the 187 port is I seriously drought it could flow less than 190-200 cfm if it tried. I call total BS on 165, even a old 283 power pak can flow 165 or better. don't tell me that the far better designed 187 is in the same league as that old power pak As far as I know there's no science to explain the 187 most people don't understand it and they don't know how to hot rod it.

 

So your saying 187 heads flow as well as brodix IK 180s? Also you are the only person in the world to ever figure this out?

 

Flow numbers are like dyno numbers....everyones bench may read abit different but i agree those sound like optimistic numbers.

Various other sources dont necessarily match those figures

 

All I know is I flowed 3 different heads that day, I had the bench for ten years at that point and flowed all kinds of heads and I could compare to anybody out there. Then I dropped that 187 on there. Maybe a swirl port head can't be flowed on a restrictor plate flow bench. Maybe it has to be flowed at 28" and not 14" with a correction factor. If what people are saying about the swirl is true, then shouldn't the head still have 200cfm flow numbers at mid lift? The whole swirl port debate doesn't add up for me.

 

got some ocean property in Arizona for you buddy.......

 

Did typing that some how make you feel better? do you need to ridicule
others to inflate your tiny ego? Is that as intelligent as you are?
Your not a Hot Rodder and i'm not your buddy!
If you don't have anything constructive to say please don't say anything.

 

Under the curve, harmonics, 305 engine builds, etc. etc. This topic could go on and on. It's been talked about numerous times on this board.

I've read all the mag articles on 305's. The TFS 305 doesn't impress me, it didn't have the RPM potential the combo wanted to keep the numbers going. It would have done much better with more cam and intake with a bottom end that didnt threaten to turn into a terrorist.

Ive also spoken with David Kauffung who competed in engine masters with a 305 (yeah, seriously) many times on the phone (thanks facebook) and it made some decent power, and that would maybe be the best running 305 that's documented I have seen.
http://www.popularhotrodding.com/tec...d/viewall.html
Ive also read stuff by David Vizard, SLP and TPiS, AS&M, etc. etc.

Matt Walter on here used to run one that prolly made close to that... and I know Fast355 has built a couple, one claiming to be 356hp IIRC. So unless this topic is packed full of HARD data that is able to be studied and ridiculed.... It's totally pointless.


The fact is you have to spin them to make the power and that doesnt agree with TPI. So the main reason for me which is "able nostalgia" is totally out the window. The approach to 305 with carb or TBI doesn't impress me. TBI guys may like it, but lets face it... Why spend all that cheddar on something that's not going to perform like a 383 or whatever? Now were going to build a 6500 RPM+ 305 that has the bottom end to take it just to keep 187's, 416's or whatever junk on top?

Im sorry, I work too hard. GM Dealer Tech in a shop with NO A/C in Texas heat all summer trying to flag my 40+ hrs to pay the bills and feed my need for "IROC ****" is certainly not going to be wasted by some ported stocker on top. If ***** comin apart... it's going back together NIIIIIICE!

 

. Lol yeah I do feel better, you're absurd get over it.

 

Some good points for sure. the fact that only a hand full people can make this motor run is a sad commentary on the hot rodding community in general. This motor should be figured out by now, there is no definitive mod to the heads, there is no combo that rules, just a truck load of negative BS. It's sad. This motor proves that it's monkey see monkey do on a 350, what a bore!

 

Not monkey see monkey do for me ... I'm building a 305 now that I'm planning on pushing to around 350+ hp ... There is a well documented thread on it "LO3 rebuild (Hp estimates)"

 

Cool, a little more than 1 hp per cube shouldn't be to tough. What i'm reading and hearing lately is the 187 head has to much swirl at high flow, fuel being spun to the cylinder wall. The poor flow numbers perhaps were guestimated by somebody from the way the motor performed. Maybe the fix is as simple as grinding a hook in at the end of the swirl vane and producing a back eddy as part of the swirl.

 

Yup here's a link go check out my thread n c what u think

https://www.thirdgen.org/forums/tbi/...timates-3.html