Ok, questions for the gurus. I will be picking up a head to do some porting work on and some new valves, guides, springs, etc. Head will get flycut to increase CR. I have a set of engine builder oversize valves. Will be running headers and either a offenhauser 2 x 1 bbl manifold enlarged to use 2 progressive 2bbl carter/webers or a 4bbl offy manifold and a 390 cfm holley. Eventually the truck will get a cam when the lower end is rebuilt. There are a couple of possibilities regarding the valves - should I run just the oversize intake and use stock size exhaust valves so I don't need to install new seats or will the oversize exhaust make that big of a difference that it's worth spending the cash for the installation of hardened seats? I'm also contemplating changing the intake seat angle to 30 degrees rather than 45 . . . long stroke, fast piston speed . . . .

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Ok...I'm certainly no guru, but here is what I did on a recent head. I put the engnbldr intakes in and ran the stock exhaust. The main reason for doing so was the head already had hardened seats and nitrided exhaust valves fitted,the intake seats were pretty worn so the small increase in intake size helped clean up that issue. I had a previous head that struck water when cutting for hardened seats,they were the smallest,thinnest recomended seats and after 5 good cuts we hit water on the last one so I am a little cautious about going to town with larger exhaust seats. If you do any porting take a look through this site,good info,these heads get thin in some port areas. I had my head pressure tested after porting to be sure there was no porosity. I'm sure others with more experience with the larger exhausts may be able to give you some better info. Cheers

Thanks! My major worry was the installation of the hardened seats, glad you were honest about the failure. Looks like the stock exhaust will be the way I go. Do have a set of NOS normal exhaust valves kicking around somewhere.
There's another big advantage of doing just the intake - I can pick up some valve seat cutters on the bay of ease and do that work myself. Machine shop time is huge $$ nowadays. I have lots of time, not so much $$. Only thing I may have done is the installation of new valve guides - have not done that before. Is that a doable job?

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

I assume the head already has standard size hardened seats? If it doesn't,it's best to hear what others say regarding them. Fuel quality,or lack of,varies widely,over here hardened seats are a very good idea,but not so sure in the US. I'd be looking at getting a good shop fit the guides for you,unless they are really good,and if your going oversize valves you will need to get the seats machined and then blend them into the port bowls when your porting. I guess if you could do it with the old cutting stones if you were really keen,but,I bet is by the time you even buy the cheapest cutters etc it may be still better value to get a good shop to do that side of things and work in with them and do your own porting. That's pretty much the way I do it,I have known the guy that does my machine work for years,he's does really nice work,after he cut all the new seats they'd were EXACTLY the same height ,I'm talking a straight edge across all valve tips and within .001"....I got him to fit new guides,rough in the new intake seats,and got a few tips for porting. I also had the old head we hit water with to practice on. I'm no speed demon when I work but I think I spent about 25 hours on it.i invested in a good long reach die grinder and some good cutters/burrs/stones and flapper wheels. I then took the head back for final seat cutting,pressure testing and machine the surface. Best do it this way so you don't nick any new seat faces while porting! I did give the seats one last blend to the bowls before assembly but all said and done it came out pretty nice and even with a basic port job you can get some good improvement. I'm sure you could get the reamers to do your own guides,plus the install tools,but for one head it's likely not cost effective. If those new exhaust valves are oversize stems I guess you could try and borrow a reamer from someone and DIY...maybe!

Engine builder over sized valves for a slant are built to factory stem diameter.


Just my two cents:
I don't under stand why one would only enlarge intake, and not exhaust valve. The whole point of the oversize project is to relive some of a slant head's restrictions.

When installing oversize valve the factory seat's thin electro-hardening treatment will be mostly if not all removed requiring a new larger harder exhaust seat to be installed. Also a high mileage head may have suffered valve recession which causes two problems, uneven valve stem height, and increased combustion chamber volume both in total and in relation to other cylinders.

You can do the porting, gasket matching and bowl clean up before dropping off the head to machine shop and save a few bucks.

I would not cheap out on machine work, save that tactic for uncritical bling projects that have nothing to do with engine or drive train.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Its all doable with the right equipment and tooling. But one thing that is often overlooked is the skill required to use them correctly. And simply having the right tools and parts doesn't mean that person is competent to do the job successfully. That's the reason machine shops charge big money, the equipment is expensive and so are people that operate it.

Are you going to replace the whole guide or just install liners? Installing liners is by far much easier and the kits from K-Line are pretty inexpensive. But you need to do all the guide work first, because any of the seat work is dictated from the guides location. And removing the guides or installing liners moves the centerline enough that you can't do the seats first and then the guide later, and you'll have to recut the seats again.

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There's no such thing as too much cam....only not enough engine!

Thanks for the info folks. Yes, would do guides first before valve seat work. My concern which was addressed was the installation of the hardened exhaust valve seats. Feel pretty confident about being able to do the valve cutting but not the seat installation. I did used to have a machine shop with a Bridgeport . . . .

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

I was hoping someone may chime in about the hardened seat options....I think it was Dusteridiot who mentioned it becoming a preference to just run stock iron seats instead of the hassle and risks involved with hardened inserts,especially if you do opt for the larger exhausts....do a search and I sure it will come up somewhere....he may have been referring to race only? Also,I think he said the earlier heads were more prone to hitting water when cutting for inserts....I can confirm that !!
The issue of hardened seats and valve recession really depends on a lot of issues and your intended use,but I wouldn't worry about any volume changes due recession. I cc'd the head stock,then fitted the engnbldr intake,it's not a huge difference in diameter,but it was obviously sitting quite high in the head and it only made 1cc change.
I'm sure you got what I meant,but when I mentioned oversize reamers for the new exhaust valves I was referring to your NOS set you have. As you probably know the factory did supply oversize stems for field repair/ overhaul of heads. If yours are oversize I guess you could open the guides up with a steady hand,a good fixture and an adjustable reamer,otherwise get the K lines fitted by someone.

Your obviously experienced with machine work and like CNC dude said,it can be done by hand but it's down to your skills,you are obviously keen on DIY and save bucks,so why not give it a go....plenty of good flowing heads were done long before the modern state of the art tooling was available....if it doesn't work out it's not like you are never going to be able to find another head to replace it!
I've never had my slant heads flowed,and I'm no porting guru,but if you get 180 cfm on the intake it's not a bad effort...200 is really the work of a pro...compare that to a Cleveland that gets 360 and you can see where the cheap power lies. I know they are totally different engines but I think the time you spend porting is great free power.
Keep us posted on your progress!