I built this head for a fellow HAMB member to go on a stroker 235. I thought I would post the pictures I took for him through the build. I started out by milling the head. I took .100 off the deck total. If you look at the following picture, you will see the thin rod under the level. It is a 1/16" welding rod. I took a .0625 angle cut, and .0375 flatcut for a total of .100. The reasoning behind that is the same reason you angle mill v-8 heads. You take more off the chamber side and gain more compression. Starting the cut. finished I corrected the intake and exhaust flange. Only reason I did this on a inliner is for clearance. You tip the head and you tip the manifolds out closer to the frame. That's the level I use on v-8 heads too. You set the level off the head before you do the angle cut, and leveling it like this will correct it. I then installed the new guides. I cut them down a little for seal clearance, and I always put a little taper on the guides after I cut the tops down. I never leave a sharp edge on the guides. Before I milled the head I measured the depth of the intake valves. I had instructions they were to be the same depth after milling. This part I don't agree with. I think they could be level with the surface, and still have enough clearance. I lost the argument though.... I then cut the seats back down. The valves sat .070 higher. Putting hard seats in now. Long ways down there This is the cutter I used to cut the intake and exhaust seats after I installed the hard seats. Here i'm setting the cutter to the valve size. And this cutter I used to make a 15 degree top cut on the intake for better flow. Original was the same 15degrees but didn't have the nice radius... After the head was done I checked the chambers. I use a 1/2" clear plastic plate, and a 60cc syringe ffrom a vet supply store. The total of the two were 76cc. Could have been around 70cc if I wouldn't have clobbered the intake down. Pump gas is no problem. stock 235 will be around 8.5to1, and a 261 will be around 9to1. Porting I kept simple and mostly blended the bowls and worked the short side of the port a little. If you use the sleeves to align the gaskets you need the flange. I don't beleive you need to enlarge the runners with stock valve size. Plus it is a street engine that is getting a mild cam. Exhaust I did the same, couldn't get any decent pictures of the exhaust becase of the location. You will need long shank cutters to get in at the exhaust. I like to have a few die grinders set up with cutters so I'm not switching back and forth all the time. Plus you don't overheat the cutters so bad that way. Let one cool while you use anouther one. Cutters get dull fast if you get them blue. Don't ask me how I know. After I port the heads I grind the seats with a Souix hard seat grinder. I give everything 3 angles, and sometimes 4. When I port the heads I blend the bottom in good, so the 60 is just there to make the seat sharp. The last picture is setting the installed height of the springs. I cut a peice of welding rod the length I want the springs to be installed at, and shim up to it. I installed new stock 235 springs with umbrella seals. The 216 springs and early 235 are REALLY weak. I went through the book and found the later 235 springs from the 1960's were way better. I have to say I'm still a V-8 guy. Kinda reminded me of a tractor head... Jeff
Don't you love mira style cutters looks like a good job well done what angle did you do the intake seats?
I used the stock intake valves so I stayed with 30 degrees. The mira cutters are nice!! The mill has the CBN too, which would be my next favorite.
Two more cylinders and the guy could have had a "real" engine!! 6inarow won't go.....................
Thanks for posting this information.I'm looking forward to seeing how these modifications wake up a 261.
Great pics! You may also want to look into bowl porting, if you go that far. The exhaust valves are pretty shrouded on these heads. A friend of mine who used to run huge V8s in muscle cars, always called my 235 a 'tractor motor' when I showed up in my truck. I like the idea - would love to see a souped tractor motor in an early traditional hot rod....
Hey,thanks for sharing,cool post. I don't follow the owners reasoning for sinking the intakes to pre angle mill depth,I just can't imagine piston to valve clearance being an issue with a mild cam in a "tractor" engine. Also with such long arm rockers I can't see it throwing off that geometry much either. Do you grind the tip of the intake valve to match the depth increase? Just thinking out loud here. Hope to see more of this build.
The owner was cool with anything I would have done, but he was under the influence of a third party control freak. I will say no more. I did trim the intake stems, but not the full amount. If I remember right around 60%. Jeff
I did the bowls, or did you mean the combustion chambers? They are shrouded all right. The mira cutter I used takes a little bit of this away. The location of the exhaust seat and the spark plug really limit these heads I'm afraid. I can see a high overlap cam helping. If you can hang the exhaust valve open into the intake stroke(overlap) a little longer, you get more of the freash charge going down around the spark plug. Jeff
Thanks for clearing that up. I thought bowl porting meant the combustion chambers. You do excellent work and sure know your stuff! Thanks again for the detailed pics. I only milled my heads for my street engines under 3500rpm, but I always wanted to see how porting & polishing is done. The milling at an angle is something I never heard anybody else do on these heads. I hope we will see and hear that motor running in a future post....!
Great job and awsome photos. Many have /or do the same for the 194-292 heads. As far as a angle cut./milling of the head. But also the head bolt landings need to be recut as well.(So they sit true) And the push rods holes must be treated the same.
Truing up the head bolt pads is a good idea, but only taking 1/16" I didn't feel it was needed. Godzilla I agree. The head gasket has a high volume. Any little bit helps. I'm not sure with the chamber design how mush compression you can run before you ping. I don't see much turbulence way down in the chamber around the exhaust valve. I'd keep it under 10to1 for sure. I think 9.5to1 could be acheived with a zero deck 261 easy. You might be able to get it to power accross intersections that way Jeff
Here is a picture of the Ross piston I had made for my 235. It was 13.5 to1 before cutting .100 off the head and block. I have not had any gasket issues and I have run it on 102 octaine with no ping. When they said every point of compression is 30 hp I said make'm tall and make'm wide. These pistons are also very light...have a raised pin that is SBC made for a 6.385 BBC aluminum connecting rod. Not your usual off the shelf deal for sure. Zilla.
Bout the time I got'er done, last Sept., I got hit by an "impaired driver" while sitting at a stop light. He was doing a little over 50mph, they figure. So...I am out of it. Sold my PU and trailer. I am going to keep the gasser project that I started last year but everything else in my garage has go to go...including RODAN (it runs the 235/250ci).
That's a bummer. Never even got to run it. I remember the post about the wreck. You always here you never know day to day and blow it off. But you really don't know. Makes life good and bad at times. Best wishes!!! Jeff
Godzilla That is the type of piston I was talking about in my post earlier under "Ultmate 235 hop up" The angle milling thing is the way my dad and I did it years ago. We never sunk the intakes either. That sure brings back some memories.
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