So I'm doing a budget 350 build for my father in law's 70 Nova. The motor sat for 20+ years in a sheltered garage until this spring. The block cleaned up ok, but the heads are a different story. They are 186 castings/fuelie heads and I'd love to try to save them, but when you factor in new valves/springs and a regrind, a better deal may be some budget vortecs-double hump clones from summit or a trip to the wrecking yard Anybody ever roll the dice without a valve job and had success with this type of pitting (eg. reasonable performance-compression)? My gut says no, but I'm just throwing it out there-
wouldn't do it, chances are the vortec's you find will need freshening up the same as these. but i think to make them live today you would have to install hardened seats in the exhaust side. i'm not sure myself which heads flow better would say the vortec's but also you have to figure purchasing a set too as versus reworking yours.
If you had the equipment you would probably have already given it a go which is what I would have done. Then if you had to replace the seats it becomes a financial decision. $$ to fix those heads vs $$ to buy a newer set of heads that actually may perform better. I'm not adverse to sticking money in special heads (for what ever reason) to be able to run them though. The problem is deciding if they are special enough to warrant spending the money.
Those won't run long, so pay your money one way or the other. Hardened seats have become a necessity, so you can put them in these heads, gamble on a junkyard set, or buy new. I look at junkyard parts as cores, you already have cores that have meaning to you, so if it were me, it would be rebuild these, or opt for a better(?) new head
Usually a complete rebuild on SBC Chevy heads....seats, guides, and the other stuff....costs more than buying new, complete HP heads, and the new ones will outperform even the old HP heads.
Scrap iron from a practical standpoint. Check the date casting numbers.The 'vette geeks pay well for date coded heads
TJ asked - ""Anybody ever roll the dice without a valve job and had success with this type of pitting (eg. reasonable performance-compression)? My gut says no, but I'm just throwing it out there-"" To answer the actual question...NO...won't work. Yes hard seats will fix the problem easily. And I'd guess guides will also be required, as well as some other machining. Not cheap from a quality shop. As others have suggested, another set of heads is in order if your wallet can't fix these. MIke
"budget build"....what is the budget? Last 350 I put together had a budget of a few hundred bucks, and it ran pretty good when I was done with it. I got the minimum valve job that the machine shop would do. With your heads, it might depend on how many valve seats are pitted. If it's only two, then it won't cost a fortune to get them fixed. If it's all of them, then find another set of crappy cheap/free 1970s heads and get a minimum valve job done to them, or just run them if they're in useable condition. But I guess my idea of "budget build" is a lot cheaper than the other guys here.
I'd go with installing new inserts a and guides, but I like old stuff and recycling what I have. If you like new stuff, buy a new Mustang or Camaro.
You can't run those heads as-is. You'd be crazy to try. At the VERY least and the VERY cheapest, you could get your hands on a set of manual (hand held) old-school valve seat cutters and clean up the pitting, then follow with a good lapping. When working with an old set of heads, I put them upside-down on the workbench and do a little test by pouring water (or alcohol, whatever) into the combustion chamber (with the valves and sparkplugs in). If the liquid trickles out they surely need some valve work.
I am fairly certain that by the time that you render these fully-functional, you will have spent enough to purchase a can of orange engine spray paint, with a pair of aftermarket aluminum heads to go with it.
Thanks for all the replies / comments. I attached another pic - most of the seats are decent minus the 2 close-ups. Let me know what you think- I think I'll purchase some new heads. The hard part (for me) is cleaning these up and seeing that they are close to adequate, but not quite there. I'll probably move them to the corner of the shop and revisit them one day when I have some more tools / another project / etc-
My normal standard for this stuff is to figure out the answer to the question "How long does it have to last?" If you want it to run for 100,000 miles, then buy new stuff. If it's only going to see 20,000 miles you can get away with spending a lot less money.
No its not. ^^^^^ I am going to go out on a limb here and say that the only thing that is going to save those heads is bigger valves. Looks like it is going to take quite a cut to get back to good metal. Anyway that would be my guess. And I still don't know how loose the guides are. Neither of that is a problem for me, I have access to the tools to cut the seats and can do bronze guides cheap enough but if you are paying someone else to do it that it an entirely different story isn't it. I may save those because I never have enough wheel chocks and look for some different heads if I was doing a budget build.
If only two are needed, they have eight here. [SBC valve seat replacement] check for fit! http://brodix.carshopinc.com/product_info.php/products_id/102322/P2-1315/16LID
Also consideration is geographic location, there are some really good machine shops in Midwest that can do work very reasonable where as someplace like LA or san fransisco could be 4 times as much and a new set would be the cheaper route
Perfect cores for some "Grumpy" level porting. I'd cut a 90 1st right above the valve angles, clean the pockets, increase the intake volume, port match...
If you have an automotive machine shop you go to, ask their opinion. They may not be as bad as everyone thinks. You'll still have to spring for springs, etc no matter what you do and it adds up.
I have fixed worse heads then those. The seats will need to be ground and under cut. Using stainless valves will eliminate the need for hardened seats.
Doesnt look bad to me...when the flatheads just need a couple of valveseats its a good day.... Cant tell if its seats in there now from pics, if so its an easy fix. If not its an hour for a machine shop with a seat and guide machine to put in a couple. Add another hour to cut the seats and your good to go. Its all about how picky you are about valve height...may even clean up but on the low side... Low budget drivable and perfect is far from each other in my book.
Please look into this.. http://enginetech.com/products/product-categories/rebuilders-valves/ Their valves should solve two problems at once. Slightly bigger dia. stems and heads so that guides and seats aren't needed. Oh, and if you want to, add some good old MMO to both your oil and gas tank to help seat and guide wear if you don't want to step up to something like KEMCO 130 Lead Supreme real TEL containing fuel additive.. MMO is an old-fashioned "top-oil" so is made for this. As is Bardahl and Wynns if they are still sold? pdq67
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