193 swirl port

[cr480r]

Just got a set of these for next to nothin. New valves & guides, and the center bolt holes have been plugged and redrilled for conventional manifold. I plan to use them on a daily driver pickup truck. I have searched, and searched and find conflicting opinions from "good for a doorstop" and "worst ever" to " they work great for what they are intended for" or "they pick up with some work". Anyways I have them and am using them, so my question is do they respond to typical bowl blend work? Or does the swirl ramp change things? I have seen pics of them with the throat area opened way up beyond what I normally see... stock there is quite a lip between the seat and bowl. Anybody here actually messed with these?

[jeff swisher]

A buddy of mine wanted to beat my old street nova and brought me a set of 461's and those had cracks in them, so off he went to find more heads.
I ended up trading him a port and bowl job for about 25 heads that were pretty crapped out. most had stuck valves and full of mud.

Anyway the best looking of all of them were some swirl ports. So I bowl ported them pushed back the pushrod pinch a bit , polished the chambers and raised the ex port roof and polished the ex port, left the intake port well blended but roughed it up.

Now the deal was to beat my nova. I had 12.0 compression with a flat top and angle milled 186 heads that I ported with a 270H comp cam 245psi cranking pressure. It would flat get it on 12.55 with Uniroyal tiger paws (60,000mile rated radial).
I could not get into the secondaries until 1/2 way through second gear.

So I told him use the new back then XE274H and the performer rpm intake and a 750 carb he had a 700r4 and I told him 373 gears and 2500 stall and that should beat me really good. He stuck the heads on a 383 stroker. He said it would hit 7000 rpm before you knew what happened.
My buddies told me his car was much faster feeling than my nova, but I moved away and did not get to race him.
So I would say yes they will work and they respond to the same stuff as any crappy gm smogger iron head.

Now I also ran a set of 1978 305 2 barrel heads with 1.72-1.50 valves on a 355" with a tunnelram and a 280H magnum cam 456 gears and it ran 12.51 at 111 mph with sticky tires in a buddies 78 nova . I ported those heads and left the stock valves and stock valve job was just lapped in.
Just a bowl port and polished the chambers etc like the swirl ports.

So even those crappy heads made a 78 nova go 12's.

[cr480r]

I am not looking to race with these, I have plenty of better stuff for that. Just want to make these the best they can be, without ruining them. I don't want to get into an extensive porting project, just was thinking a pocket blend unless it will reduce the "screw" effect. Cam is 196/206 if that gives you an idea of the rpm range I plan to operate in. Stick shift,3.73, 33" tire..

[cr480r]

What about adding 2.02 intakes and let the machine shop use a bowl hog on them? I have some cheapo valves sitting around.

[jeff swisher]

Bowl blend them it will not hurt them at all and call it a day, it will be worth it, no need to get crazy with them, and I say no to the larger valves many times in most cases.

My buddies nova with the 1.72-1.50 heads got updated to another pair of newer 305 heads casting 601
I installed 1.94-1.50 valves and a step larger cam 292H comp magnum it now ran 11.94 at 116-117 mph.
crappy converter.. but still not bad for a daily driver on 7-11 gas,, and this one is shifted at 7400rpm for best ET.
No need for 2.02's

I think for what you are putting together it will run pretty well.

[Tuner]

Those heads only require 24-25 degrees total advance for WOT. Vacuum advance is more or less like other Chevys, 15 degrees, start 6", max at 15" or so. They do not need as much WOT timing as any other Chevy head.

[user-612937456]

IF i had anything set setting around I would use them over the 193's the ramp in the port is a choke that restricts any air flow above 2500 rpm and you will probably find your engine running out of power at about 4000 rpm the ramp is intended to create turbulence at 1500-2500 rpm supposedly to increase efficiency and emissions at cruising speed and they do a poor job of it at that. almost any head that The General made will get better fuel mileage and make more power. Last is you run a factory cam these heads are spark chatter and ping factories unless you have a properly operating EGR system to quince the combustion chamber temperature. Without the EGR you can run 93 octane fuel and have the timing so low it wont pull a greasy string out of a cats ass and it will still ping. I would only use these heads to repair a customer's oem unmodified truck or van. For any other application would be useless

[Tuner]

It's a wonder an engine will even start with those heads on it, is that what you really mean?

The OP said, "I plan to use them on a daily driver pickup truck." Those head are fine for a daily driver, excellent torque, power and mileage. Much better head than the nay-sayers who have no experience with them can understand, until they get their own experience.

[jeff swisher]

What GVX stated is the same thing that people stated about the 305 heads.
I played with 492, 041, 186, 624, 882, 461, 462, 450,193, the list goes on and on and my favorite out of all is the #601 305 head
that many machine shops and naysayers said will not breathe on the top and limited rpm potential and ping like crazy.

Well I will say they are the best head I have ever ran for factory head that is ported. even with the 1.84-1.50 valves they came with they will twist right up 7000+ rpm with smallish cams. quickest set I done with 91 octane in a daily driver 350 was 11.50's 76 chevy stepside.
Like tuner stated until you get your own experience with a certain set of heads you do not know what will happen.
But I will say those 193's have not proved to be a bad head at all.

I did read somewhere where someone ported them 193's and wrote it all up with pics etc.
Team Camaro or chevelles.com or possibly here. and he left the vane.

I am sure you will run them as stated keep us posted on the results that you get with them.

[cr480r]

The only other heads I have around here are some 200cc aluminum NKB 2.02 deals, and some 76cc 1.72 307 heads. The short block has dished pistons. I don't remember the cc' s now but with them .015 in the hole, a .026 gasket, and 64cc it calculated to 8.94:1... So... Open chambers probably aren't gonna happen, and I should probably keep the NKB's for a more suitable build.

I had a '91 tbi truck a few years back. It had 180,000 on it. I thought it had good power from 600-2600rpm and fell off starting around 3300, but was nice to drive with a 5spd. It was completely stock minus the cat. This engine will have more actual compression, a Q-jet on a iron 1970 300-350hp manifold, a ramjet roller cam that is much larger than tbi cam, and maybe even some small headers... If it will pull above 4000rpm when needed, I will be plenty happy.

[rfoll]

Pretty good chance the 91 truck had 193 heads on it. The screw port actually has pretty good volume, and some of them are only 58 cc combustion chambers. Every engine build does not have to be a racer. I have a set of these, and my research says to leave the ramp alone and work on widening next to the valve guide. If they are in good shape and don't need lot's of money to be useable, give them a try. The worse thing that could happen is you lose the price of a set of head gaskets.

[cr480r]

Rfoll have you used the set you ported? Other than old posts by fast355, nobody seemed to post results of their efforts.

[jeff swisher]

here you go. read this.

http://www.thirdgen.org/forums/tbi/2832 ... 193-s.html

[Bob Hollinshead]

From another thread on swirl ports: All I did was knock the casting flash off the intake, reworked the intake bowl area and swirl ramp (swirl ram is still in place), then reworked the exhaust like you would any small block head. I also unshrouded and opened up the chambers slightly around the intake and exhaust valves. The heads still exhibit very strong swirl. While cleaning them I sprayed water into the intake port and recieved an unexpected shower. The swirl port literally threw water out in about a 6' diameter area. The heads were flow benched at 28 in/h20 just like any other head.

Notice how much better the exhaust flow is than the intake considering the intake is through a 1.94" valve and the exhaust a 1.5"



Valve Lift------Intake Flow---------Exhaust Flow
.050--------------35.6----------------------31.0
.100--------------72.4----------------------60.5
.150-------------105.8---------------------87.3
.200-------------133.4--------------------124.2
.250-------------154.1--------------------147.3
.300-------------180.6--------------------171.5
.350-------------195.5--------------------184.7
.400-------------209.3--------------------196.3
.450-------------217.4--------------------203.7
.500-------------224.3--------------------215.6

So how do you cam a motor when the intake flows just about the same as the exhaust? And what's the power capability of the head? 300hp?

[Plaintoast]

I did a real low buck build with a set of these, left the ramp in place, pushed the pushrod pinch jump thing smooth. Using an old single plane (not the best choice) a small hydro cam, 87 octane pee water, it was making 360 ft lbs as low as we could pull the dyno down. HP was 263@ 4500, and fell off like a cliff after that. My notes also say it only wanted 22 degrees total, I think we were around 8:1. Its currently still in a magazine car with 40,000+ miles and gets 22 mpg cruising. They have a place, high rpms isn't it, but they certainly make a decent torque/low rpm head.