Inliners International Forums General Discussion Hi Performance 194 head question

On a 250 with factory compression (8.5-1?) what approximate compression would I have running a 194 head?

Ah, The proverbial can of worms. The use of 194 heads has been discussed here quite a bit over the years and never seems to come to a conclusion that we all agree on. There are several old threads here on the subject but searches are not very easy. I'll post a link to one about a truck engine I still haven't finished yet. (usual for me) This is a 292 low rpm truck engine build not a race engine but there is some basic 194 head info that may be of interest to you.It starts out about cam choice but gets to heads soon.

The easy answer to your question is you could expect from 1/2 to one point compression gain. So 9 to 9.5 to 1.

LINK

By the way, what part of Nevada?

Like beater said ballpark can be 9 to 9.5 -1 depending what has been milled from the head Or the block.

So far the parts I've compiled are:
12 TRW .030 over 2289 NOS pistons to make 6 good and have some spares.
12 Perfect Circle .030 over 50514 NOS piston rings to make 6 good and have some spares.
GM NOS points distributor.
Bare 194 head from Mr HotRod6.
Lumps from Larry (Twisted 6) uninstalled.
Mr HotRod 6 valve cover adapter to run 235 valve cover.
Chevrolet logo 235 valve cover.
Mr HotRod 6 water outlet.
Clifford single carb intake manifold.
Clifford shorty headers.
Weber (Clifford) 38/38 2 barrel carb.
Davis Speed Equipment alternator, power steering brackets

This is going in a 83 Chevy C10 truck.

Camshaft is likely next on the list but they seem in low supply, although I'm not usually in a hurry: I suppose that discussion is in order.


I'm in southern Nevada (Las Vegas area), moved here when I retired from the Navy. Thanks for the link (reading).

That was a great read, thanks. What valve sizes did you end up going with? (sorry if I missed it)

So far I have a good starting point with this 194 head:



I plan on doing as much of the work myself as I possibly can (i.e. first time)

Thanks Larry!

Most people use the 1.84" intake valves in these heads for milder builds. Valve shrouding becomes a problem after that and requires chamber relieving to offset it.

Thank you, so its fairly common to run the 1.84" valve without the chamber reliefs?

It does not take a lot of work to unshroud the valves. I mean yes it does take work and time, but not all that much and if you're going to do it why not just step up to a 1.94 and then the head would be ready for any other upgrades. That you may want to do at a later date.

Ah, The proverbial can of worms. I haven't done anything on my head yet. Right now the plan is stock valve size and just thin & reshape the boss. I want the most velocity at low rpm and I think the volume is adequate for my purpose, a low rpm truck engine. One thing that is said about the 194 head is that by the time you add & un-shroud bigger valves you have a 230-292 chamber head. Twisted6 & CNC DUDE have a lot of experience here. 12 Bolt Tom has done Dyno tests with good stats on higher rpm setups. As far as I can tell there is still some gray area for low end power. It all comes back to the toughest of all hot rodding engine build questions, " What do you REALLY expect your engine to do?" It can not do everything and each of your components must work together to reach your goal.

Thanks Larry, could a shadee-tree type dude unshroud for a 1.94 valve at home? What tools would you recommend? and then does anyone hapen to have a pic of a 194 head with a 1.94 valve unshrouded?

Here is a "194" head discussion that was done a while back. https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=54365&page=1

I personally think the 184 valve is the proper size to use in a 194 head. The chamber could still use a bit of opening up. I have also seen a # of 194 heads hit water when trying to go to a 1.94 valve.

lol, well I would say there are likely 3 answers to that but all happening inside the engine bay of my 83 Chevy C10/likely bolt to a TH350
1. initial setup; will run the single 38/38 weber on clifford manifold with some camshaft yet to be determined
2. Phase 2 (if I get to it); run dual weber 38/38 carbs on a dual inlet clifford manifold (have the carbs that need rebuilt/no manifold)
3. Phase 3 (if I'm feeling especially froggy); maybe some nitrous oxide

Thanks Tom, really excellent hi-res pictures! Do you have any pics of a stock 1.72 valve in a 194 head for comparisons sake?

I could get some pics. I won't run them. They are the bottle neck of the whole engine.

That would be most excellent!
I was thinking I could get an idea of what/how much de-shrouding might be necessary (to even run a 1.84 valve) by seeing the clearance for a stock 1.72 valve in a 194 head for which it was engineered for; hope I said that so it made sense.

The 194 head is/was intended to run on the 194 block, which has a much, much smaller bore than the 250/292 engines. So that makes the airflow have to kinda dogleg in and out of the cylinders because the chambers overhang the bores so much, further compounding the shrouding issue. Relieving the chambers can help, but wont eliminate it completely, but it does help.

Tom, Thanks for posting that old thread. That was the "can of worms" I was thinking of. What ever became of the articles & books containing all that information? We used to be so lively here. Too bad some of the pictures no longer work.

I'm still going to try a 194 head on my 292 truck motor. If it doesn't work I won't have much invested. I think it will fill my low end needs.

I plan on using my 194 head as well. I remember communicating with a guy named Mike Kirby a few years back and he didn't seem to think the 194 head would be a limitation of any kind; albeit, more work to get there.

Thank you! Appreciate the info. Now if I could only get an image of a properly relieved chamber.....

Just about any head can run the risk of hitting a water jacket when going to a 1.94 depending on the core shift of the casting The same goes for installing bigger exhaust valves when Installing the Wrong valve seat. The 194 head is not really a bottle neck Like some seem to think. And those that don't know them Like they think they do. Mike Kirby, Glen self and Like Many Others Ran those heads. Even the One's I have done SET track records Over a brazed in lump ported head. Yes Like Scott said it was designed for a small Bore , But the intake Port and Valve size is still the same, IT is the CC side of the head that makes It not wanted by Many. But they can Flow very good Numbers in the end. And if I didn't know what I was doing Or talking about My stuff never would have been Published.

So now let the Games begin.

Here are the requested pictures of a 1.72 valve in a "194" head. Both closed and open to .500. The caliper shows the distance from chamber wall to valve.
Also a picture from Armond Orr and his write up-To find out what kind of valve to cylinder clearance we had, I did a little experiment. I cut a 3 7/8th inch circle from construction board and centered it over a cylinder on the block. Using a ball peen hammer, the head bolts holes were cut out. This was laid over the head and the area where the cylinder head overlapped the block was marked with whiteout. 1.94 intake and 1.625 exhaust valves were put in @ 1/2 inch lift. As you can see, a 1/16th drill bit would not fit between the valve and the cylinder. a 5/64th bit would just fit on the exhaust side.
This is shrouding!

Wow, thanks Tom, really appreciate taking the time to do all that work/setup; sincerely appreciate it. I wonder what a 1.89 LS valve would look like in there. When I was talking to my buddy a few years back about doing some headwork he suggested using LS valves (at least I think he did/memory being what it is and all).

A bore chamfer will help as long as it stays north of the top ring land.

Tom, Thanks for the pictures and comments.

Panic, As always thanks for the insight.

Larry, Thanks for insight & references.

And Scott you too!

Hank, Now I understand why you traded your Clifford Intake for my Offenhauser. I may need to find another one.

Moregrip1 I really don't know what to tell you. If your engine will see 3,000 rpm often the other head might take less work or at least easier work. For my low rpm truck engine I see compression & velocity on the bottom end as a bigger + than greater flow in the upper range where my cam won't work anyway. I might be persuaded to go with a 1.84 intake but even that might cut velocity. It may make no real difference at all. I will do some shaping to the bolt boss and clean up the ports a little to help speed the flow.

It seems like every time we do this new/different information or at least pictures & ideas come up. Good discussion guys!

First picture is a 194 small chamber that has a 1.84 valve and had chamber wall opened in the head shop. Second picture is Small chamber 194 with 1.84 and now has the chamber walls formed by hand. Remember, the intake flow is toward the sparkplug side of head. Have 3 of these on the head bench right now.

Whoa! That's what I was hoping to see, thank you. The negative area around the valve looks very similar to the pic you posted of the 1.72 valve in an unmodified chamber! (maybe a bit more)

Great pictures! What exhaust valve size is this being prepped for?

Personally, I would never install a 1.94" intake on a 194 cylinder head, had too many problems hitting water jackets destroying the heads.
I had better luck by turning down a 1.94" intake valve down to 1.90", then unshroud the chambers. But even with a 1.90" valve it's pretty thin.
For better durability, ( a bit safer) I would just use a 1.84" valve.

MBHD

Hi Beater,
what are you implying?

MBHD

"Hi Beater,
what are you implying?

MBHD"

Just saying that you knew the Offenhauser makes more power at the bottom end. I was more concerned with a Clifford that matched my valve cover. Since I was planning to use a turbo I thought either would work for me. Now I don't plan on the turbo so an Offy might work better.

It is nice to have matching parts but like you stated the Offenhauser gives more bottom end.
I will add it gives you better drivability and would think better mileage.

Lump port the head and the clifford will do just fine in the low end.

That's the plan. I have your original lumps and the 194 head from MrHotRod6.