Chevy 193 Swirl port Mission Impossible

[Carnut1]

The deep bowl is really the only advantage this design has as far as gross flow. Thanks

[juuhanaa]

This picture was recently shared in another thread;

5A3974CB-D7F0-41F0-AECB-6D81078C196D.jpeg

Im thinking of a choke point at the bottom of the bowl or apex area and then expanding from there into the chamber. Would that help overcome the small valve and fluid in the back of the bowl?



-juhana

[Monza355]

If you get this combo to run 10’s in your heavy Chevelle. That would be very impressive! Looking forward to see more!

[jeff swisher]

I love stuff like this.
I was told in the 1990's I needed headers and aluminum aftermarket intake to run in the 13's with my 1978 Nova.
I built a 350" engine for it with 186 heads I worked over with 1.94-1.50 valves and then ported the Cast iron Q jet intake and ported the iron exhaust manifolds.
Stuck in a 270H 224@ .050 flat tappet .470" lift and ran stock rockers and stock pushrods and Z springs at 110 seat pressure and fired it with a single point distributor.

Duals with glass packs and Uniroyal tiger paws 275-60-15 Full weight car by the way but no idea on the weight at that time.
Ran a Q jet carb also.
3.70 gear in a 9" rearend and had to take it easy on the launch or the tires would spin. 1.8 60 foot and ran 13.028.

Later stuck the Performer RPM on it with a 750 AFB and headers and went 12.55.

I have since gone in the mid 11's at 3000 lbs with the 601 305 head and at 3300 lbs went 12.51 with the 2 barrel 1.72-1.50 head in a 357" and 280H cam.

9's in the 1/4 will be smokin fast but maybe.

These above were not even close to 9's but would rev to 7000 easy.

I did build one 383 with the 193 swirl port heads for a friend.
Full weight Monty and 700R4 with 3.73 gears cam was the XE274 and I ported the heads and left the stock valves and left the stock valve job.
I just lapped the valves after porting.
I left most of the swirl vane and the idea was for this car to beat my 12 second Nova.

I heard it would beat it but never got to race him as I moved away and life happened.
He did tell me the sweet spot on shifting it was 7,200 rpm. Anti pump up lifters and Z springs set at 110 seat.

They will rev.
Heck my 1.84-1.50 305 heads will rev to 7800 rpm and not be nosing over.

Keep us posted on your results of course.

OH these builds were all heavy junk cast pistons and thick rings also so maybe some power there

[Carnut1]

Nice to know swirlies will rpm that high. Thanks

[F-BIRD'88]

I'd suspect if you were to first grind out /remove the swirl ramp and then epoxy up the intake port you could then carve out a decent flowing port with enough volume too.

[F-BIRD'88]

Just like all the other oem sbc heads the porting limitations will be the bolt hole between intake ports and the pushrod pinch side wall.

[Tuner]

Nice to know swirlies will rpm that high. Thanks

The trick is no more than 25 degrees spark advance.

[Tuner]

I'd suspect if you were to first grind out /remove the swirl ramp and then epoxy up the intake port you could then carve out a decent flowing port with enough volume too.

That swirl ramp is your fast burn combustion rate enhancing friend. The only reason these heads get the bad rap from gear heads is people ignore the fact that they only need 25 degrees of spark advance and that they do not tolerate any more than that, even with a high octane fuel that does not knock. Power drops fast beyond 25. Next time you get to road test these heads, try it for yourself. With a sporty cam they still need initial like any other Chevy head, but a short advance curve that only totals at 25.

[F-BIRD'88]

The swirl ramp is great for part throttle low rpm driving to create mixture motion but at high rpm the chamber swirl becomes too fast actually impeeding high rpm intake flow inti the chamber @WOT. It becomes a restriction to high power flow. Yes those engines with the swirl port heads have quick combustion at relative low rpm resulting in only needing modest spark. advance

Not going to help on a 9.90 et pass.

[Tuner]

FBird, you are in this thread about these heads 10 years ago.

https://www.hotrodders.com/threads/flow ... fo.242554/
Cridder Discussion starter
277 posts · Joined 2010
#1 · Sep 18, 2013 Flow bench tests/numbers for TBI/TPI intake port 187 casting, aka Swirl port.

These numbers are to correct the misinformation out there about the Swirl port, the flow numbers for the HO head as you will see below cannot be interchanged with the swirl port, the swirl port is in fact a far superior head in this regard.

On this day of testing back in 06 I flowed 3 heads, #1) a HO head # 14101081 in used condition and cleaned up for testing. #2) a 350 smogger with fresh v/v grind # 9889338, (very similar to the 882 casting,) 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 a 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

I Think whom ever designed the swirl port is one smart cookie

[1980RS]

Well I am glad to see the OP trying this. You never know what the potential is until one goes outside the box and tries it. No different ten my L-29 heads with the swirl ramp in those intake bowls. I pretty much cut them out when I did the heads as one head porter told me "you don't need that ramp in there, we're racing not looking for fuel mileage" must have worked I ran 11.10 on my 1st pass with the L-29 heads that everyone told me were door stops.

[Carnut1]

Nice to know swirlies will rpm that high. Thanks

The trick is no more than 25 degrees spark advance.

I learned this when I first modified these heads in the 80's. Thanks

[PRH]

A few years ago I was looking thru some info on the net about the swirl port heads.
There is no shortage of info out there, and I found many flow numbers……and as you d expect from the net, the numbers varied wildly.
I’d never tested one, but fortunately I had an untouched example in the shop.

Looking at the head, I didn’t see how they would flow as much as some of the on line numbers would suggest.
My instincts weren’t wrong.

191 head with oe valve and valve job.
Tested at 28” on a 4.00 bore, clay entry radius:

Lift———flow
.100—— 57.9
.200——109.6
.250——128.9
.300——141.6
.350——145.2
.400——149.2
.450——152.4
.500——153.6
.550——155.2

Without digging thru my notes to verify, I’m saying this is easily the poorest flowing oe SBC head that comes from the factory with a 1.94 valve.

[Tuner]

A few years ago I was looking thru some info on the net about the swirl port heads.
There is no shortage of info out there, and I found many flow numbers……and as you d expect from the net, the numbers varied wildly.
I’d never tested one, but fortunately I had an untouched example in the shop.

Looking at the head, I didn’t see how they would flow as much as some of the on line numbers would suggest.
My instincts weren’t wrong.

191 head with oe valve and valve job.
Tested at 28” on a 4.00 bore, clay entry radius:

Lift———flow
.100—— 57.9
.200——109.6
.250——128.9
.300——141.6
.350——145.2
.400——149.2
.450——152.4
.500——153.6
.550——155.2

Without digging thru my notes to verify, I’m saying this is easily the poorest flowing oe SBC head that comes from the factory with a 1.94 valve.

Without digging thru my notes to verify, I’m saying this is easily the poorest flowing oe SBC head that comes from the factory with a 1.94 valve.

191 head has 1.84 valve