J-(Chicago)

Next time you decide to do a 307, we'll toss a 40 grit belt in my sander and let it ride until the belt catches fire. We'll finish hone it on the glass patio table out back.

Welcome back.

83hurstguy

with more cam and a computer delete, that turd would be in the 13's. Have hardly touched it to finish the BBO swap. Damn house projects keep getting in the way.

I gotta get back to Chitown... miss seeing all the crew up there. Good thread you guys got going here.

Smitty275

Well, if he raised the roofs 1/2" I'd like to see it. There is not that much material before you hit water. My guess is either he didn't raise it that much or he ground through and filled it with epoxy. Now that would leave about 1/4" of the rocker stud pad. Not so sure he's holding them in with only a 1/4" of thread engagement. Most likely he miss typed or doesn't really know. The wall thickness around an intake port is only about .180" thick.

If his car runs what he says it does then its one heck of a runner, no doubt.

As for sleeving pushrod holes. Drill them to 9/16". Get the 9/16 x .014 wall tubing to sleeve them from a hobby shop. Cut it to length and loctite or epoxy it in place. If it drills right on size you may have to polish a little off the sleeve to get it to fit.

cdrod

What's the benefit/purpose of drilling and sleeving the pushrod tubes? I don't understand.

67 Cutlass Freak

The only reason for this is a max effort porting job. The push rod holes are the pinch point near the entrance of the intake runner. If someone hogged into there accidentaly, during porting, this would be a good fix. If you want to see a picture, look at my thread about "Aftermarket Heads or Port Cast Iron", on the first page you will see some battens that had the push rod holes sleeved.

cdrod

Is this something that is done to remove more material from the intake port? I guess what I'm trying to say is this is done only as a repair or do you do this intentionally to open up the intake port. Thanks!

67 Cutlass Freak

This is done for a max effort head or a repair. Bill Trovato, from BTR relocates these holes on his BTR-Brock heads, & uses offset rockers. He starts with bare castings that do not have the push rod holes bored yet. When I get home from work I can post alink if you need to see them.

Smitty275

Cut into it intentionally. Then sleeve after all work is done. Getting that material out of the way allows better access to the rest of the port along with better flow in the finished product.

67 Cutlass Freak

I wanted to discuss installed spring height and valve stem height measurement. The spring height is measured between the spring seat and the lower lip of the retainer. It's important to get this right so the closed valve spring seat pressure is correct. You want to measure with the retainer and keepers that will be used for final assembly. Some keepers have the ring at different heights than stock. The spring height mic I have was made by Powerhouse Products-





This picture shows a "C" casting, stock head, with low miles that has never had a valve job. The measurement shows 1.662" in height. I believe the spec on this was 1.670" That means the spring will be installed at .008" lower, or more tightly compresses than the OE spec. This is just fine. Let's say the measurement was 1.690", this would indicate a .020" shim would be needed under the spring to set it up correctly. If you are running aftermarket springs, the installed height may be different, so you should consult the manufacturer. If you just got your heads back from the machine shop and find the same thickness shim under every spring, chances are they measured a couple and averaged them out. Not really the best way to do this.
Measuring the valve stem height is also very important, especially if you're running the stock, non adjustable rocker set up. A lot of machine shops performing valve jobs on Oldsmobile heads, have a hard time getting this right. Most of these guys do a hundred Chevy's to every Olds that comes through the door. Chevy's have adjustable valve train, so if the valve stem height is inconsistent, it really doesn't matter. If you are building a performance olds engine, I strongly recommend upgrading to an adjustable valve train. With roller rockers there is less friction, they are stronger parts, they also help you to correct for variances in the valve train. You have to remember modern head gaskets, like the common Fel Pro blue, are thicker than stock. If you have milled the head, or changed push rods, all of this comes into play for getting the right lifter pre load. The lifter pre load is how far the pushrod cup in the lifter is compressed below the snap ring. Ideally this distance should be .030"-.050"
This is a stem height gauge part number HG-455 that I purchased from Mondello over twenty years ago. It is pretty much idiot proof for setting up stem height-


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If you are planning on running stock rockers, buy one of these tools and drop it off with your heads when you're having a valve job done. When performing a valve job a slight amount of material will be ground off the valve and the head. This changes the installed spring height and the overall stem height. You can also use a dial indicator or make your own height gauge. Here's one I made for measuring the stem height on Olds 394 engine-


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If you have just started planning your performance Olds build there's some very important things to consider. First and foremost what are your goals and how will your car be used. If it's strictly a drag race car, how fast do you want to go? A better question might be - how deep are your pockets? From the beginning we have been stressing the importance of having properly matched engine components. The only way to do this is to have all of the information about your combination ready to present to your engine builder, so he can steer you in the right direction. For example he will need to know the weight of your car, what transmission you are running, what differential gear ratio do you have, what tire wheel size, what type of fuel system are you running, and what modifications have been done to the chassis. Once you know all this then your builder will want to know what type of fuel you want to run. Now he can help you figure out what the optimum compression will be. Now you can choose the right head for your needs. Now that you know all that we can get a flow number and choose the right cam and valve train as well as intake and carb set up. I didn't type all this just for fun, but I think a lot of guys just start picking up random go fast parts at a good price, that really won't be the best performing engine because it was not planned out properly from the start. I'm talking from experience here. I am guilty of this. My engine was assembled and torn apart three times before I was satisfied and even fired it up. Now looking backward in time, if I could do it all over again, it would be totally different. Poor initial planning on my part.

captjim

^^^^^^Good post. Just to add a little to it, if you are planning on roller rockers, you will probably want to tap the bolts out to 3/8" from the stock 5/16" Again, the planning is sooooo important, that way you can completely machine the heads while they are apart.

Smitty275

With the equipment available today getting all the valves the same height is easy. When a head is in a seat and guide machine it is leveled end to end. A stop is set on the quill and every seat cut to the same depth. The guess work of using stones to cut seats is gone. Unless of course your using a shop that hasnt bought a piece of equipment in the last twenty or thirty years. Same for the valves. They are put into the grinder to a stop and the new face is ground to the same place on every valve. Even if a shop doesn't have a newer valve grinder most just clean up the seat area which normally is within a couple thousandths valve to valve and is close enough for them to still get the same shim across the board.

If you going to go to adjustable valve train and roller rockers go straight to a 7/16" stud. Your doing it for strength and stability. So don't bother with the 3/8, go to 7/16, you'll be glad you did. Once the quest to go quicker starts, it never stops, and your always looking for more.

captjim

You are right, but my point was make your decisions before you begin and stick with the plan, that way you only do things once.

67 Cutlass Freak

Smitty I agree with you 100%. With todays modern valve job equipment there should be no way to mess up a set of heads. This is still happening though. This post was from last month. Jag1886's machine shop must have equipment from the stone age, pun intended-
https://classicoldsmobile.com/forums...ed-height.html

507OLDS

Nothing state-of-the-art at the local shops here. One reason might be that they are barely making it,as a business,so they don't buy new tools or equipment.There are a few guys here that are truly talented,but they have nothing to show for it. You are either not doing good work,or you are not charging enough.Since they are backed-up with work for a good year out,I am thinking charge more.It will weed some out,and make a better business.

67 Cutlass Freak

We have discussed a bit about match porting the runners to the head inlet, but I would like to cover that in more detail later when I have some photos to share. I haven't discussed porting aluminum in this thread yet, but I will say it is much easier than porting cast iron. The bits used have to be an open type so as not to clog up. The dual pattern carbide bits will clog up immediately when used on aluminum. The material comes off a lot faster so it's easier to make a mistake. Try to be smooth with very light pressure and keep your tool moving. I will say that match porting is not where your biggest gains are made. No matter what, you don't want the intake manifold runner to be larger than the intake inlet on the head. The air fuel mixture will bounce off the lip and create all kinds of turbulence. I wanted to talk a little about porting the plenum area. First I wanted to show some pictures of a SB Victor that Jim from J&S Machine did a lot of work on-
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What he has done here is smooth the radius on the top of each port so it's more of a straight shot into the runners. The angle of entry is much smoother. Remember the air doesn't like making sharp turns. He has also smoothed the floor of the plenum area and narrowed the dividers between the ports so there's not a blunt surface to bounce off of. It might be difficult to understand what I'm talking about without seeing a before and after example. So now I'm going to show you my BB Victor that I ported. I do have before and after shots of this one.
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When I'm porting the plenum, I just try to visualize a clean smooth path for the air fuel mixture to travel down. I am trying to reduce flow restrictions. I was told not to sharpen the runner dividers. Obviously the plenum area is the largest volume that the runners all scavenge from. The runners are not fighting for the charge all at the same time. Only when the intake valve is open for any given cylinder then that runner is flowing. This happens extremely fast inside your engine. When I got done porting this intake I bead blasted the plenum and runners to aid with atomization. For Coppercutlass' engine we have picked up a used Edelbrock Performer RPM intake. Somewhere along the line someone did a poor job porting it. Looks like they took some material off the floor. We may have to have it welded up. He's going to mark them and we will share the progress. I would like to hear everyones thoughts or opinions on cutting down the center divider on the Performer intake. Has anyone done back to back testing? Is this supposed to give better low end torque? Anyone care to show photos of their ported intake? I'm going to port an old cast iron 4 BBL intake for Jeromy. He likes that heavy metal ****.

J-(Chicago)

Haha you know it. me buying a street dominator would be a lot easier though. Much like milling a set of good j heads to small block chamber size is easier than all that port work you're doing on those sbo heads lol.

There's more than one way to skin a cat. That is the purpose of this thread.

coppercutlass

Taking the road less traveled sometimes is more fun it beats the hell out of this.

67 Cutlass Freak

We're not skinning any cats here. Hey moderator why didn't you reprimand me for the fowl language? I apologize, just trying to inject some humor. Bernard Mondello hooked us up with some valves for your heads J. They look real good. He had to dig through a few sets to find some that measured good. I'm sure he got them from the same place as the other set I got for you.

455man

I had read that cutting the center divider is supposed to help with upper hp because it opens both sides up to be used instead of only sucking from one half of the carb. It's an attempt at getting torque for the street and HP for the track. Not sure on back to back tests.

J-(Chicago)

The funny thing is, everybody yanks out the chinese procomp valves and put better ones in. I hope they're worth a crap. I have my doubts with stuff out nowadays. Bernard seems like a good guy though.

coppercutlass

The new slogan should be built olds tough with chineese stuff lol jk.

olds 307 and 403

Are the J's actually better on the exhaust side than small block heads? The ports have an awful short roof. They look a lot like my 4A heads from the pictures but with same size valve and obstruction under the #8 heads. The roof looks higher on my #8 heads. Just wondering , I know they are better on the intake side but not a whole lot, once a bigger intake is installed. Problem is who knows what numbers are right, they all seem to be different.

J-(Chicago)

The ports are big block dimensions, so it's a free port job right off the bat.

The bowls do suck, but I just run a cutter down those. 2 hrs on the drill press, pay the machinist to mill them to sbo chamber size, and you're done. I believe they are 2" intake and 1.62 exhaust.

captjim

If you wanted to do an relatively inexpensive high-winding SBO, you could get a pair od C or E heads with the big valves, do a little bowl work and good valve job. If you had the equipment or found a pair in decent shape, you could get where you need to be and save some $. Bore to 4.125" and go the SBC piston/rod route. With some gears, compression, and cam, it would be a runner.

J-(Chicago)

You got it, buddy.

The key phrase there is "Had the equipment/found a set in decent shape".
That's the hardest part when dealing with 45 year old stuff.
Good post, and idea, Jim. I've never seen a performance engine that didn't enjoy being bigger.

Another thing to think about, if you want a 400 horse small block olds, your heads probably only need to flow around 200cfm. That's easy. Porting a sbo head is doing it the hard way if you're going to order custom pistons anyway.

But if you find your pockets are empty, than porting a good pair of sbo head cores doesn't sound as horrible.

J-(Chicago)

Now, sinking 1200 bucks into totally re-doing a set of small block iron heads with wimpy ports is borderline insanity. also, spending 1200 bucks on bbo edelbrocks for a sbo and then paying a bunch of money to mill those is also wasteful in my opinion. Especially when your fuel pump won't even fit.

I'm glad dave is having fun, ulysses is learning a lot, and i'm getting a decent pair of heads out of this thread. So far, the efforts and discussions seem worthwhile.

67 Cutlass Freak

J - I think you hit the nail on the head here. What I really don't understand is why people think the Edelbrock's are so much better than the big valve "C" castings. Yeah they're lighter, but in stock form I don't see $1800 worth of performance gains. I am having fun, but I should have just given you one of the pairs of stock "C" heads, I have 2 extra sets of. I'm really interested in what other people have to say about running the BB heads on a small block. I have never done it. But I have a dome piston short block engine ready for mule testing. It would also be interesting to flow both of the SB heads I'm porting here against each other. The port jobs will be identical but the valves in your heads are larger. You should contact your guy with the flow bench to get some pricing information on having a few sets of heads flowed at the same time. Don't forget, I still need a junk BB head to cut up.

J-(Chicago)

I have a 4A, a 7A, and a J head here set aside for you. I couldn't find any older castings that were totally shot yet. I have 1 E head that's cracked from too much nitrous, but It's been fully ported. Not sure if that's helpful for a baseline for you.

Smitty275

Really no need to cut up a head to see what's inside. The port wall thickness is basically 3/16". Naturally there is minor variance for core shift and what's rusted away over the years. But that is basically all you need to know. And unlike aluminum heads there is water between the bowls where they are close together. So you have to be careful in that area.

I've seen BBO heads on SBO many times. Sometimes they've been screamers and others have been real dogs.

captjim

Let's be fair here, and I don't believe that statement is. We gotta compare apples to apples. How much will you have in stock heads after a good valve job, dividers welded, rocker holes tapped, and crossovers filled? $1,000, maybe less if the valves are re-usable. So, now you are talking $800 for lighter heads that flow better. Different question, IMO.

olds 307 and 403

From my understanding, those stock big valve BBO flow numbers Mid Am are very inflated. Either head needs milled for SBO, all I care about and run. Then there is the fuel pump issue. The only mechanical that isn't POS and flows enough is the RobMc pumps, correct me if I am wrong. There are many electric pumps with very high flow ratings for the same price. The only reason I plan on irons, have known cores, plan on using stock rocker arms, porting myself and reusing valves. If I could get a pair out of box with SBO chamber size, Edelbrock or Procomp, I would collect scrap money for them. It is just one more cost that stretches my budget too far for this year. Unfortunately the 5 of us SBO people, won't convince either company to offer them.

DENT

This is a good thread for us do it your selfers , Im in the process of porting some 72 350 #7 heads . I have done some porting of W30 F heads about 30 years ago,( I was young then lol) it was a great car and ran in the 12's. Also did some 350 heads back in the day. The heads I'm doing now I plan on using them on a 403 I have . Yes I know all about the week bottom end. Its gona be fun anyhow . Keep up the good work.
Oh , remember to have fun , I am.

67 Cutlass Freak

Good luck with your build Dent. There's a few guys running the 403's. They do pull pretty strong. You might want to talk with Jim from J&S Machine about adding a Halo girdle to the bottom end. I think it's cheap insurance. Back at the beginning of this thread Captjim was talking about match porting the combustion chamber to the block. I think that would be a real good idea for what your doing. I think we are going to do this with Copper's heads so keep following along and we will post some photos. The other suggestion I have for you is to drill out the heads for the larger head bolts before porting. Be aware of where those head bolt holes are and try not to port into them. The 403's had relatively low compression so using the #7 heads should help with performance.

Smitty275

WOE THERE PARDNER...... not trying to be a smarta$$. But be careful trying to open the chamber of ANY earlier Olds head to the bore size of a 403. The odds are 99% in favor of hitting water or springing a leak a short time after you get them on an engine and running because they will be so thin in some areas. I only say this because I know of several who have tried it and what the end results were.
Besides you'll be adding a lot of volume to the chamber which will require a lot of milling to get the chamber back to a useable size. By time your done you end up with a week deck also.
Do as you please but please do so with caution. A hole in a combustion chamber can cause catastrophic engine failure that leaves nearly nothing reuseable.

67 Cutlass Freak

That does make sense Smitty. I have not messed around with the 403 stuff. Do you see a lot of problems with the mismatch of combustion chamber to the block when trying to run this type of combo? Is there water jacket alignment issues? Do you think there is enough material in the chamber to unshroud the intake valve? Glad you shared your experiences so we didn't have a sprinkler here. Do you think Dent would be better off porting the 403 heads and having them milled? I do know someone that bolted ported BB heads to a 403 that ran pretty strong.

Smitty275

Personally I would mill a set of BBO heads to 68-70cc and port them.
The mismatch in chamber size is going in the right direction so it is not a problem. The bore is bigger than the head chamber which leaves a small "quench" ring around the entire cylinder. Because of the way the air flows through an Olds port you don't see the benefit of unshrouding one side of the intake valve that one might expect. Ours is not like a BBC where nearly 35% of the intake valve is shrouded and the air holds to the top of the port and favors the shrouded side of the valve. Ours flows heaviest on the floor and the narrow area of shrouded valve is not a high flow area to begin with. If you get everything just right and hold you tung right you might find a couple of cfm. I honestly don't fight for those couple unless its a serious competition engine because its so small a gain 99% of engines would never realize the difference.

Smitty275

The water jackets when changing heads are no problem at all.I think only engine that poses any problem is the 260.

J-(Chicago)

I'm with smitty. The 403 heads are total crap. 1.5" exhaust, small block runner and a bbo size chamber.

Go to your local gym.... work out hard, and once you're in prime physical condition, chuck those heads as far as you can throw them. that's about the best achievement youcan make with em'

Bernhard

Hi Smitty
How about matching the bore to head around the intake valve by chamfering the bore?
Not to the point of head gasket failure or hitting water.
Have you ever done this mod on a big block Olds?
If you have would you mind sharing your thoughts?

Smitty275

You can only chamfer down to the top of the top ring. So there is not much to chamfer. And since an Olds head doesn't flow heavily to that area I really doubt you'd see any gain. Especially on the 403 heads that don't move much air to begin with. The motors that benefit the most from chamfering the bore are those with canted valves that barely miss the bore walls and have airflow that is heavy to that side of the port.