The Jalopy Journal
Discussion in 'The Hokey Ass Message Board' started by SLAMIT, Jan 20, 2011.
Watch our Bonneville thread, we are even talking about a 261 combination
I thought 1/8 "= .125"?
I shaved my 261 head and cut down my valve .100 according to Clifford's recommendations below. Also bored to .60 over. ARP main bearing and connecting rod bolts. Tapped and plugged for a full oil flow/filter. Drilled and tapped the front of the crank to accept a Powerforce #PPS-90000 6 3/4 Dampener and small block Chevy 7/16" bolt. That's it so far...
Building your new engine takes some doing and to get 320 ft lbs of torque, unless you follow these simple instructions:
Please do not let your machinist talk you out of milling the cylinder head .100. It is O.K. to do.
1. Use Clifford rebuild kit with chrome rings, .060 or .080 over pistons.
2. Use 264 hyd camshaft.
3. Mill .100 off the cylinder head, SINK INTAKE VALVE ONLY, blend runners, pocket port and polish valve pockets, cut the top of the Intake valve .100.
We stock custom made intake oversized valves. Order them and you will gain over 60% horse power and torque.
4. Install Clifford High Lift Springs and retainers on the lowest valve groove at 1.700.
5. Use Clifford 6=8 Headers and Intake manifold with a Weber 38 carb kit or 390 Holley 4 brl carb.
That's what I meant, haha! 1/8" or .125". Sorry for the confusion!
correct me if i'm wrong, but if you're using an 848 head on a 261 you have to drill a couple steam holes in the head, right?
yea why not get more hp/trq to start out with?
also the oiling is better from the factory.
I always get the two confused, full flow vs. full pressure.
it does one of the other that the 235 doesnt.
the 58-62 ones are the ticket. the 55-57 still has the same oiling as a 235
and as for the being stuck thing, if you cant get it unstuck just search around and you should be able to pick a buildable one for a couple hundred.
In the article linked above it is stated that milling 1/8" off the 261 head was equivalent to removing .030" from the higher compression 848 head so one needs to be certain of what they are starting with. Recessing the intake valves enlarges the combustion chamber which is completly opposite of what is desired by milling the head reducing benefit. I have spent a great many hours digitizing, sectioning, chamber shaping, porting, and flow bench testing this head and continue to collect data.
Yup. And if you actually want them to do something useful and intersect the jacket drill them at 12 degrees from the face like GM did.
I have read and reread a pair of articles that Pat Ganahl wrote in an issue or two of Street Rodder in '74 or so about building a 235, and if I can figure out this new computer, I'll post them here. The second one dealt with prepping the head and shaving it was a large part of the deal. I do remember that he recomended o certain threshold before you had to sink the valves, and I believe it was .060. I'll check it out later and see if I can scan and post.
turds make you blush? that's kinda weird
What are the benefits of an aluminium flywheel? Besides the weight savings.
Best post in this thread.
Too many amateurs have been hacking up and milling the crap out of good heads because of the info written 50 years ago. Good heads are hard enough to come by without someone wrecking them
OK, here goes. The head was angle milled to reduce the chamber volume (yes, more could be removed) with a small rolling of the head combined with the shifting to the left put more of the chamber over the cylinder allowing for a larger lump on the piston.
Thus more compression. Remember to spot face and/or redrill the bolt holes to the new angle. We ran an end mill thru the holes to offset them for clearance when we moved the head to the left. A safe bet was about an 1/8th to 3/16s move of the head. We tubed a couple heads to go farther, but you have to check the valve to cylinder wall clearance on a 235 at max lift, but no trouble on a 261.
The use of a sbc balancer helped to reduce harmonics and off set the reduction of mass from the use of an Al. flywheel. This shows in the bearing wear pattern. A good balance job is important for a happy engine at higher rpm.
We notched the piston for the intake valve clearance rather than sinking them. It worked better for us. This was done by the use of a valve with cutters attached to the face. We also shimed the rocker stands when a head was milled to correct rocker arm geometry.
The carb jet was an easy fix to reduce the oil to the top end. It was a drop in fit at the head to block face and was agustable.
Cut pistons, that's self explanatory. Weight reduction.
Picture #4 in Curt B's post should be studied real close to get the most out of these heads.
If you use the 848 head on a 261 and move it you also need to move the location of the steam holes to match.
Always use a pair of head bolts with the heads cut off or some long studs to align the head and gasket on installation and push the them to the driver side even on a stock rebuild for best results. There are no dowel pins in these motors for head and gasket placement.
I guess I'm showing my age, but What is a 3/4 cam?
I order cams by lift, duration, centerlines, ramps and etc......
But have never ordered a 3/4 cam! Just what is it?
I used to race a stock class, that required a stock cam. So in that class, a stock cam, was a full race cam. So what is a 3/4 cam? A ground down stock cam?
Its a generic term for a cam 3/4 of race cam specs. Race cam is also a generic term, haha! Generally speaking, a 3/4 cam is hotter than mild but milder than race.
Knew you would find this thread Tom, meant to call but got busy with kid, the car and a pal that may have wheels for dads 56!
CrkInsp, thanks for the tips. I like how you cut off of the heads of the haed bolts to aid in installation.
How did line up your pulleys when using a small block balancer? I'm using the Powerforce 6 3/4" harmonic and put a single pulley off a 283 on the front of it. This of course moves the pulley forward from the stock location (behind the balancer) and wonder what you did to line it up with the water pump pulley? What pump did you use? I have 5 1/2" between the front of the block to the back of the rad. to play with. Otherwise I may have to move my rad. forward.
Thanks for the help, Peter
Another SUPER post.
You might try this balancer - spendy but made for a 235
OK i need to see the car in that avatar. way cool!!!!
Thanks for the reply. I have been trying for 40 years to find out what I had.
I just today drug a '53 235 home today. Then dropped it down the trap door in the front of my Brooklyn brownstone apartment. "Why not put it in the garage?" you might ask, because I am a poor hillbilly in Brooklyn, and my garage fits my car like a condom! I look forward to your all's input and knowledge. Good and Bad!
Love those 235s. Had one in a '55 Handyman wagon in the 80s, and had a great time with it. Had one of those 3X2 manifolds mentioned earlier, but could never run it as the engine just couldn't breath.
My motor was basically stock bottom end and used a stock intake, but had a milled head, and Clifford single collector headers. If I had it to do again, I'd definately put in a better cam and 2 or 3 single barrel carbs. Love that look.
Aluminum flywheel is used to reduce rotating mass, which is supposed to allow the engine to rev quicker. Supposed to be good for drag racing, though the Ramchargers used to run big, heavy flywheels on some of their slant six cars so they'd launch harder. Don't think I'd mess with it for the street.
My 51 Has the stock 216 but I'm trying to track down a 235 for it.
The only questin I have is, I know this is a thread about the motor but how about gearbox's. Would my stock 3 speed coloulm shift handle the increased power and torque of a hopped up 235? What gear box's are you guys using? How did you adapt them and while I'm on the topic what rearends are you using? Iv got a 9" ford sitting at home, not sure weather or not it's worth putting that in or not?
Thats funny cause i got one of those Tom langdon HEI coil thingies that didnt bolt in the orig spot 2 years back and not paying attention i just didnt put the bolts back in and i drove around for a few days like that. shit every where. ha ha
Thanks for the link 6inarow (Tom). Ouch... you're right, a bit pricey, but would definitely due the trick.
Patrick's says the 4 speed Saginaw is good for not letting the revs fall so far between shifts. Supposed to be a direct swap for open drivelines.
4 speed Saginaw??? What's that out of?
Just worked out what rearend im going to use. A 54 dodge sedan diff should do the trick. (iv just gotta take a couple more mesurments but I recon it will fit easy!
Saginaw four speed I had came from a Vega. Not sure what else they were used in, but I'd guess monzas, and the like. Think small, light duty, mid to late 70s or early 80s.
My personal observations from building a few 235's and a 261 performance engine 10 years ago..I'm building a 261 as we speak.I'm just a backyard mechanic.........
Stock replacement pistons such as Sealed Power will sit about .070 below the deck in a 261.With a 848 head you still have no real compression.Info I have found says a stock 848 head has a 80cc combustion chamber.But I have never cc'd a head myself to verify this.Anyway,do the math,you need to have the piston at least no lower than.020 below deck with an unmilled 848 head to get around 9-1 compression.Getting some compression on these engines really wakes them up.
Heavy milling on the head and sinking the intake for piston clearance is the wrong way to go for performance.This just shortens the already piss poor intake port short side radius and limits breathing even more.
My own experience was that with the piston at around .020 below deck,a mild cam of 210 degrees duration at .050 lift and minimal overlap will have the intake valve clearing the piston with a more or less stock head.But you always have to mock up the engine and check for valve to piston clearance like any performance build up.Something like the Howards M4F cam grind is what I used.Going wild on a 261 cam makes for a lumpy low speed engine with little gained on top end.Why beat the shit out of an old engine for 10 more HP?
A carefully assembled and balanced 261 with a mild cam,9-1 flat top stock pistons,short tube headers,a couple of properly tuned carbs will make 170 hp and still have the low speed power of a stock engine.
Some Flattie guys would kill for a smooth idle 260 cube engine making 170 hp
So what are the best ways still in the affordability range to bump the compression on these motors. I am realizing that milling the head a bunch is not the way to go. Is there any affordable pistons for raising compression??? and how about milling the block???
Compression is a great way to add power and wake up any engine. I know this but seems like an expensive challenge on the inliners. I also have heard that just an intake and exhaust wakes them up a ton.
Lets keep this going i am so eager to learn more !!!!!!
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