dctrumpet

iTrader: (10)

My upcoming project has lead me to dig deep into the RHS heads that I am installing. They are a 76cc combustion chamber and because of their chamber size it lead to a lot of controversy when i stated that I was going to install them on my 350TBI, etc. The RHS i have are 2.02/1.60 valves with a little better intake runner design.....

So, I did some research. I currently have 14102191 heads on my setup now. I could not find adequate specs on this until i did some diving in.

I will do a BASIC comparison of the 191 and the 193 heads as many have asked that question.

From what I find the ONLY difference between 14102191 and 14102193 heads is the combustion chambers. They are both a high swirl port design. They have fairly restrictive intake runners due to a ramp cast in the bottom of the bowl which causes that high swirl.

The stock 191 and 193 heads are not considered a performance head, but are good for fuel economy and low-end/bottom end torque. The 191 76cc design i believe allows one to use 87 octane fuel.

191 and 193 center bolt design

191 have 76cc combustion chambers
193 have 64cc combustion chambers

191 1987 & up 350's mostly trucks and marine applications
193 1987& up 305/350 mostly 350's, but were installed on 305's(L03) as well

191 1.94 intake 1.50 exhaust
193 1.94 intake 1.50 exhaust

This is nothing earth shattering, but it's here for future reference. I believe the casting on the 191 is better for mild modifications compared to the 193 head. Again, this is from 8-9 hours of research on the net and phone calls to guys I trust.

Check out what this guy did with the 193 heads. Very interesting. Let me know your thoughts...

http://www.herningg.com/projects/groovyheads.html


Hopefully, this has been helpful

five7kid

iTrader: (14)

I believe 191's being 76cc is a misstatement.

dctrumpet

iTrader: (10)

It's not, but thanks
----------
3 engine builders stated they are 76cc chambers. They know that by measuring the chambers with a 100cc glass buret. Also, various machinists online have posted their findings.

Not trying to argue, but there is a 12cc difference between the 191 and 193 heads.

dctrumpet

iTrader: (10)

The first thing I am going to do when i pull my 191 heads is to measure the chamber size. I could not find anywhere that the 191's were 64cc.

I realize as a Moderator you need to point out potential error in threads and i respect that completely. Trust me that I have done my homework and challenge others to do more research on this. The more the better. Not like it's real important to find the differences between 191 and 193 heads, lol. Know what i mean?

Sonix

iTrader: (1)

I'm anxious to see your results measuring with a burette. As you've talked to some machinists, and other people on this forum have said the exact opposite of what you've found.
I think phone and internet people have equal merit. I want hard results to prove it

five7kid

iTrader: (14)

It's important if you think you're going to maintain your compression ratio if you go from 191's to aftermarket 76cc heads.

Places that say they're 64cc:
http://www.chevytalk.org/fusionbb/sh...hp?tid/195574/

Most references don't list any chamber cc, and most seem to parrot Mortec.com (which doesn't list any information but engine size and years).

dctrumpet

iTrader: (10)

That link states that the 191 heads are believed to be 76cc. If you follow the additional links at the end of that page to paceperformace you will find this information:


CYLINDER HEAD SPECS:

CASTING NUMBER 14102191

SWIRL PORT INTAKE PORT DESIGN

76cc COMBUSTION CHAMBER

1.94" INTAKE 1.50" EXHAUST VALVE

VALVE SPRING PART NUMBER IS 3911068 (SAME SPRING USED WITH THE OLD 300H.P 350 CRATE)

INSTALLED HEIGHT 1.70" PRESSURE @ INSTALLED HEIGHT IS 80 LBS * PRESSURE WITH VALVE OPEN IS 267 LBS.

THESE SPRINGS ARE GOOD FOR .550" LIFT BUT CLEARENCE BETWEEN GUIDE AND RETAINER MUST BE DOUBLE CHECKED BEFORE ATTEMPTING.

7 BOLT EXHAUST FLANGE
----------
mortec.com is not real helpful other than finding out the year and engine a particular head was used.

dctrumpet

iTrader: (10)

As a general rule most on TGO are correct with regards to using a 76cc head on a standard 5.7L engine. If it's not setup correctly compression will take a dump.

From my research pertaining to the 191 heads on the net I found either no listing of chamber size or a listing of 76cc. No where did i find 14102191 listed with a 64cc chamber size. Not one machinist or engine builder stated that the 191 head had anything other than a 76cc chamber.

Tim Wilkerson's Master Engine Builder in Springfield, IL stated the same thing. Do some research on Tim Wilkerson. #1 in points for top fuel NHRA. I live 20 min away. He was my first contact and he gave me 6 additional contacts who deal more with SBC's than he does. So, I did contact them. 3 said they were not for certain or couldn't recall and 3 stated for certain that SBC cylinder head #14102191 were 76cc chamber heads. One machinist told me to call his buddy in SoCal who does marine engines. He stated "Sure's the F*#K they are 76cc heads" LOL

Well? All of that convinced me, but I am like Sonix... I will prove they are either 64cc or 76cc when i pull them sucker's off.

I liked this challenge because it caused me to dive deeper and I came across a wealth of knowledge and contacts for future reference.

I am not trying to prove you guys wrong. I am just trying to state what i found and obviously, no one else has dug this deep into basic, average 191 and 193 heads.

dctrumpet

iTrader: (10)

Please know that I am going to find out what i have with regards to pistons, deck height, etc.

The ONLY reasons why i bought these heads is because they were $500 and flowed better than the 083 and 906 heads by at least 27cfm and I was informed by RHS/Comp Cams, Edelbrock, Brian Harris, etc that these were perfect for my setup.

Yes, I am still a novice/newbie/not experienced, etc with all of this stuff and that is why all of you have been so valuable with your comments, recommendations, etc.

Believe me I am still trying to find out more on this topic.

dctrumpet

iTrader: (10)

http://forums.chevyhiperformance.com...pet/index.html

Quote from the above link.
"This is a well traveled road. Let’s start with the heads these are swirl port 14102191 or 14102193 castings. Take a look and check this out. These are low compression heads of about 74 to 76 cc in the chamber combined with a full dish piston. This makes a rather lazy chamber in terms of squish and quench. You really need to get compression and agitation up. The heads can be milled .030/.040 which will add about half a ratio..."

Here is is stating the 193's have a 74-76cc chamber which is wrong..

I emailed them and YES, 191 is 76cc.

dctrumpet

iTrader: (10)

http://www.edgesz28.com/edgesZ28/sub...ban-engine.htm

327_TPI_77_Maro

iTrader: (8)

Flow is nice but if you still have the stock dish top pistons w/ 4 valve eyebrows (14 to 16cc total dish), with 76 cc heads you are barely 8:1 compression. That is a huge hole to dry to dig yourself out of performance wise. "low compression" 9:1 setups can work well but 8:1 is really really low. I would sell those heads if you don't have the motor assembled yet. Do it right the 1st time, I have learned that many times over. You can buy new 64cc heads in the $800-900 range. It's not worth saving $300 to put yourself at a huge CR disadvantage that will be hard to overcome. I just went through this with a virtually new crate 350 I got, that had dish toips in it. I ended up putting flat tops in it and having to balance the rotating assy, because I didn't even have enough CR using stock dish pistons and 64cc heads, for what I wanted for a street motor. Cost a little more up front but it will be worth it

dctrumpet

iTrader: (10)

The way this whole thing got started is I bought a reman 350 from Advance Auto 2.5 years ago. Did all the basic tbi mods noted here on TGO and hedman shorties. Then I did nothing for two years.

I got a beautiful 9bolt rear end with 3.27 gears, new calipers, rotors, etc for NOTHING. A patient owed me some money and we traded. That lead to installing a 3" high flow magnaflow cat, 3" magnaflow cat back, all of UMI's parts, aluminum drive shaft dropping the fuel tank and installing a 255lph fuel pump from Brian Harris (tbichips.com).... etc.

Then i wanted to do a simple upgrade to the top end. LT1 cam and keep my stock 191's. Well, I found a new 7.4L TBI base for next to nothing (literally) and a set of 65# injectors. I got an Edelbrock Performer TBI and had that bored to 50mm to match the 7.4L base. So, I came across these RHS heads. I knew NOTHING about them and heads in general. I asked around, called Comp Cams, etc and they said it would be perfect with the 8-304-8 Comp Cams cam.

So, I hopefully have the right deck height and style of piston, but I wont find that out until i tear the top end down in the next few weeks. Worst case scenario I will sell them and get something better suited. I was originally going to get a set of 180CC AFR heads, but they were $1500.

I was told that my combination would yield a strong 365-375hp. Who knows. I am going to dyno it before I start this project. I want to know what the stock 5.7L with all the ultimate tbi mods and exhaust yields horsepower wise. Then change the heads, intake and cam and redo the dyno.
----------

I agree. The more i am learning the more i am waiting on starting my project.

five7kid

iTrader: (14)

Based on the CR differences between HD and regular LO5's. A responder corrected that by saying the piston dish is what changed the CR, not the chamber volume.

At any rate, get a reading on them and let us know. Yours are unmodified, correct?

Fast355

iTrader: (2)

I will agree 100% with you. After having about 10 of these HD TBI 350 engines, mostly fullsize vans and school buses, here is what I found. The chambers on all 350 swirl port heads are roughly 65cc. I have not found a single pair that are 76cc. The difference in the HD and LD when it comes to compression ratio is the piston. I will have a HD 350 apart here in the next week or so and take pictures of the pistons in it. I know for a fact this piston has the deep 18cc dish in it. This engine had 810 swirl ports, but the 810s are direct replacements for the 191s.

dctrumpet

iTrader: (10)

My stock 191 heads are unmodified.

dctrumpet

iTrader: (10)

This is the exact reason why i started this thread. "No one" seems to know what they are. Has anyone on this board actually measured them? I can't comprehend why the guys that I have talked to would lie about the combustion chambers on the 191 heads.

If you have a 100cc glass buret and you place it over the combustion chamber and slowly release the contents of the buret until the chamber is full and you have 24cc left over I would say that is a 76cc chamber head.
----------
Believe me I will be the first one to admit if I am wrong. I will measure when i pull the heads off. I do have a glass buret.

Fast355

iTrader: (2)

The heads I have cc'd (193, 191, and 810s) were all right around 65cc (gm never cast them completely consistent and I even had one with a 64 and a 67cc chamber on the same cylinder head).

dctrumpet

iTrader: (10)

Awesome. That's the proof I want to see. Someone on TGO whom I know that has actually done it.

Thanks Fast355

dctrumpet

iTrader: (10)

I value your opinion will you review the information i have attached and let me know what you think of the RHS heads. I am not looking at high performance. I just want something that will match my 8-304-8 Comp Cam and something better than my stock 191 heads. This assumes the 76cc will work for my application.

Here is the link and the pdf file is located at the bottom of the page.

I paid $500 and they are new. Is there a better head for near that price?

kdrolt

It's much cheaper for the factory to use a single mold pattern (giving 64-66 cc chamber) and dial-in the actual CR by using, or not using, dished pistons.

So the passenger car L05 gets 193 head, non dish pistons (with eyebrows for the valves) and 9.3 theoretical CR. Light trucks get the same head and (probably) deeper dish pistons. Medium-duty trucks get the 191 head, and heavy-duty trucks get the 810 head (fatter exh stem using sodium-fill for better heat transfer).

The above comments are based on my observations from the few people that have bothered with the 187/191/193/810 swirl castings, and these observations come almost exclusively from TGO or FSC. The rest of the web sources on TBI head info is sparse and not very accurate because very-few-people bother with them..... especially after the years of posts incorrectly associating them as junk heads. HTH.

lynmar2

I just checked My 14102191 heads and I also get about 66 cc's (65.8)

fullsize fun

​​​​​ for a couple hundred bucks more you can buy set of blueprint engine 190cc 64cc chamber heads