The Ultimate 235 Hop up Thread.......

Here's a story that goes down that road:

http://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=437492&page=1

 

Did you read the whole thing? if you have a '48-newer truck (or a truck bellhousing), this part is of no use for you....

 

BBBuuuummmmmppppp! lets hear more about these great little engines.

 

54 235. 30 over Jahns popups. 848 head. McGurk cam. D&S intake, dual Chrysler ball and ball carbs. Mallory dist. Started with a split exhaust manifold, ended with a tube header.

Fun. Had a sound I'll never forget. Shoulda kept it (the motor... still have the car)...

 

I documented a head I built for 6inarow a while back. I angle milled that head 1/16 (.0625) and flat milled it the rest of the way. If you can take more off of the combustion chamber side it dosn't quite effect the intake valves as much. Even if you do run pistons with the bumps milling allows you to do more work to the cumbustion chamber without reducing the volume.
Here are a couple links to the album and the thread I started. For some reason the pictures don't show up. I'll try to fix that when I have more time.
http://www.jalopyjournal.com/forum/album.php?albumid=10779
http://www.jalopyjournal.com/forum/showthread.php?t=276475
Anyone ever spend time on one of these heads with a flow bench? I'd like to try raising the exhaust valves a little out of the pocket and tip the spark plug up tward the piston.

 

Thanks Dyce, I was going to post teh same questions tonight!

Lets talk FLOW, what to do to get one of these Stovebolts breathing WITH a stock head!?

 

See my earlier post

 

what would be a good electronic ignition system to replace my points in the 58 belair 235....maybe a website or 2,,,im tryin to order some stuff soon,,thanks,,and what else could i possibly do?

 

You can use a Ford TFI module to fire a high energy coil with your existing points. Your points will last much longer because they no longer carry primary voltage, they just act as a trigger for the TFI module.

You get to keep your correct (looking and functioning) distributor, you can hide the TFI module easily and if anything takes a dump all you do is replace the condenser and change a wire to go back to your old point-and-condenser system.

You need the grey TFI module without pins on the side. Look for early 90's 5.0

 

If you have any more info on the flow test, or pictures of the crossections I would thank you very much if you could share. The pictures you posted answered a few questions for me already.... Have you flowed a head with the valves recessed and compared it to a head with the valve seat flush after milling? A nice transition area between the deck of the head and the valve can be a good thing too.

 

I suck at documenting but every alteration I have done involves zero handwork and is 100% repeatable on a machining center so one day I plan to just load it in the mill and hit start. I am farming out valve seating and flow bench work and am still waiting for numbers with larger powerglide intake valves but haven’t pushed either. My major observations so far are:

Don’t ream/enlarge the runner from the manifold side as I’m told it is already big enough to support a Hemi. Cutting here makes the sharp turn at the sides where it opens up even worse resulting in the charge failing to negotiate the turn, bouncing off the back wall and becoming disorganized. Even a wedge, lump, or turtle shape on the back wall didn’t improve things much. The sharp turn to the valve at the sides is THE worst feature.<O

Exhaust flow is the bigger issue and is partially restricted by a bulge in the chamber wall. An Inliner documented his efforts using a piloted tool which I tried and have yet to submit for flow testing but this method seems to sacrifice a lot of chamber wall. I have gone there with a lollipop cutter but again have no numbers yet. Here’s his post on the subject:<O

“My 848 head's intake ports have been opened up and ported just as it was detailed in the hop up article written by Frank McGurk and published in the May, 1955 issue of "Hot Rod" magazine.
This head was ported in the early 60's and has not been used since the previous owner switched to the later engines when thay became available in 1963.
I purchased the head for my 261, and had it 'freshened' up, (cleaned, new large powerglide valves, springs, etc.) by a very reputable speed shop in my area.
While he was at it, I had three cylinders flowed on his 'SuperFlow' flow bench when he was done. I thought you might be interested in the results.
As freshened, the intakes flowed 200 cfm at .500 valve lift at 28" depression. At that point, the flow 'stalled', indicating port saturation. In other words, increasing the valve lift had no further affect.
Surprisingly, the exhaust was far more restrictive than the intake. As originally tested, the three exhaust ports chosen 'stalled' at 100 cfm, again at .500 valve lift. The graph generated showed a very large dip in the flow at .300 valve lift. All ports tested were very consistant with these results!
Looking closely at the exhaust valve and the combustion chamber, it was noticed that the combustion chamber wall bulges in towards the edge of the valve, before receding away as the valve opened further! The chamber wall shrouds the exhaust valve at exactly .300 lift! This was clearly indicated by the exhaust flow graph.
The speedshop machinist piloted a small boring bar in the exhaust valve guide, and opened up the chamber wall to unshroud the valve, and the ports were retested. Now, the exhaust flow increased to 120 cfm, again at .500 lift, and the large dip in the flow was gone!
The results were 200 cfm intake, 120 cfm exhaust, all at 28" depression, .500 lift, and a smooth flow curve.
I hope that some of you may find this interesting. Toolman”<O

Here’s a couple pic’s of the chamber shaping and the flow bench adapter and for full section views click on webshots in my signature and then the 848 head album

 

Thanks Curt

 

Terd, Killer link! Thank you.

 

Thanks Curt!! Really the flow numbers are better then I thought. A 261 has the same cid per cylinder as a 350. I have to do some calculations to see what your flow data will support for rpm. A gain at .300 lift is better then a gain at max lift.

I wonder if there would be any improvements to exhaust flow by changing the wall on the intake valve side of the chamber. It reminds me of releiving the block on a flathead in a way.

On the cam, has anyone really done much testing on grinds for this engine? With the location of the exhaust valve I wonder if the engine would be affected by high overlap the same? My gut tells me you could run more duration without getting reversion. Any thoughts?

 

You're totally welcome! I whole heartedly recommend Patrick's. He's very knowledgeable. And don't be put off if a sweet lady answers the phone, she knows quite a bit too.

 

I saw this over on another thread and figured you guys could appreciate this.

 

Anyone have any insite on the cam? This discussion is to good to let it die out!!!

 

Frank McGurk pioneered dual pattern cams for Chevy sixes with good results. He found that the engines really responded to more lift and duration on the exhaust lobe.

 

Oh yeah,
and in 1943 I'm pretty well sure the guys with the stock V8's were looking out for you and your terds





oooooh yeah,






.

 

subscribed!!

happy to see this thread.

i have a 58 235 im buildin with a mcculloch supercharger.

gonna be pretty wild i hope. its going in a 51 chevy kustom so i dont really need the crazy horsepower or anything. would be nice but im building it look and sound crazy as i plan on driving the hell out of it once done.

this thread has alot of helpful info for sure!

 

I thought I read they have two part numbers, one car bell housing and the for the truck. I could be wrong though.

 

If you look at the article below, even McGurk used EXHAUST heat for his manifold! Its quicker to heat up and the FACTORY did it too when your was all one piece! JMHO....

 

I use one Pertronix Ignitor with a 50,000 volt coil. Then I can open the spark plug gap an extra .010+

http://www.pertronix.com/prod/ig/ignitor/default.aspx

 

Hey guys, I am in the process of collecting parts for my 50 GMC buld. What carb's are best to use with the Offy 2X1 (or 3X1) intake, on a slightly warmed over 235 (milled heads, 3/4 cam)?

 

Here's a good place to start:

http://www.thecarburetorshop.com/Dual1barrelcarbs.htm

Even the best carbs will lead to disappointment if they are too much for the application or if poorly syncronized which is highly likely with a lame "adjust by bending" linkage. My opinion is that an intake with a pivoting rod/threaded ball joints is what is needed to have a streetable setup that stays put.

 

Cant wait to see that truck back on the road. Althoug I still wish it were mine Buwawawawa.

 

Its all good bud, I think you are going to like what my plans are for it, hopped up 235, white walls, 4" drop, freshen up the drive train the drive it until the wheels fall off.

 

I just picked up a 1960 apache. It's got an inline six, but I don't know which one. How do I find out which one I have? Does any one sell mounts to install a vintage air system on one? Thanks for the help.

 

BTTT!!! ftwkustom, did you ever get that supercharger on there????

lets see some pics, I'm kindly dreaming about a blown 261 in a model A with a lasalle trans and a steep gear in the back!

 

Two Carter-Weber 2 barrels on a 50's Edelbrock 216 intake, '56 235, '848 head'. Four bolt plates installed by 'Buffalo Steve' on the left coast, rather, Washington state. Maiden voyage 18.7 mpg on a 1k round trip and that was 65-75 mph. Engine is smooth and stronger, pulls over the mountain pass near me at 65 mph.




'62 3sp+od, '57 3.90 rear, daily driver only vehicle...