how do i rebuild my chevy heads myself?

Question

I have 350 heads im trying to rebuild on my bench and need advice on how to rebuild them at home any advice would be great thank you

Answer 1

OK, it can be done at home on a bench, but you will definitely need a good instruction manual, a sturdy bench with a bench grinder with a brush and stone, good light, a parts vat, and special tools like a good straight edge, two feet long, and a valve spring compressor that you may be able to rent.
The thing about doing heads is ;
1) The valves must be seated properly with full contact in between the valve faces and the valve seats.
2) The surfaces that meet with the engine block, exhaust manifold, and intake manifold must be flat.
3) The heads and all components must be clean.
4) The freeze plugs must be good, with no corrosion.
5) The valve guides must be good, with minimum play at the valve stems.
If these things cannot be achieved, or if you believe that it will take too much time or effort, then send them to the machine shop and pay to have those things done.
First disassemble the heads, and label and categorize everything. Number the valves, associate the springs, keepers, and other related parts with that valve. Intake and exhaust valves must be kept separate from one another. Lay everything out on the bench. Use plastic bags or tags to keep up with everything.
Check your heads for flatness on all surfaces. If they are not flat, send them to the machine shop for resurfacing. Check the valve seats and valve faces and valve stems for wear, and any discoloration. Also check valve stems for straightness. Roll them on a flat surface and look for any warpage. If there are any questions, pack it all up and send everything to the machine shop.
If you have heads that you can manage to reassemble, vat everything to clean it. I used Draino in a plastic 55 gallon drum. I mixed 4 containers of crystal Draino in the drum 1/3 filled with water. Easy Off also works. It took a full day, and the parts came out looking just as good as new. When finished, the fluid can be flushed down the toilet. The grease will have been dissolved, and it will help your toilet.
Use the manual to reassemble the heads. Take measurements of your springs, check spring height, and once you assemble the keepers to the valve stems, tap on the stems with a hammer to make sure that the keepers fully seat and will not come apart once the engine is running. You don't want any dropped valves after all of the hard work. Lap in the valves, and test for any leakage or seepage by pouring brake parts cleaner (it leaves no residue) into the ports with the valves installed.
Hopefully this may help get you started.

Answer 2

It would probably be cheaper in the long run to take the heads to an automotive machine shop unless you have skills as a machinist and the proper machining tools. The valve seats may need to be reconditioned and unless you know what your doing you could screw them up. Also the valve guides which are just molded into the heads on GM engines will probably be worn. A lot of machine shops just knurl the valve guides which works fine for awhile but wont last as long. GM recommends re-boring the valve guide holes and using valves with oversize valve stems. The machine shop will also check your heads for war-page and cracks. If they are warped the machine shop can machine the heads. You cant. If they are cracked you would need new heads. I like doing my own maintenance myself but some jobs are best left to the experts with the know how and proper machinery. Also on later model GM engines they have what are called torque to yield head bolts which means they actually stretch out a little bit when torqueing them. They should not be reused.

Answer 3

With the inventory 1980 smogger heads, 400hp isn't gonna take place. whether they're ported. you're particularly putting a large cam right into a smog 350 and putting a reasonably greater appropriate carb on it. If that's a 2-bolt important 350 it probable does not have overall performance heads. 2-bolt important blocks are annoying even with what human beings think of, yet you would be finding at 230-250hp tops with those heads and that blend. Get used Vortecs for like $4 hundred and additionally you're able to fulfill your potential targets if something is geared up proper. yet I trust the different guy, i might pass with a large block. For off-roading and moving an extremely heavy vehicle, a geared up 350 could be no longer as good as a comfortable 454. you go with low end torque no longer superb end HP.

Answer 4

the year of the 350 heads would have been nice but some heads don't have valve seats and all you can do is lap the valves but if it don't have valve seat i would take to machine shop and have them put in most valve that don't have seats suck the values in the head and most need valves guides. new valve spring are a must unless you have got a spring tester to see the pressure and then you have got to shim the spring.so get new valve springs lap the valves with compound and get a good mating surface on the head and valve.

Answer 5

Go buy $1500 worth of used tools from Ebay
or
Call you local machine shops and tell them you are trying to get out cheap , they might cut your valves and seats cheap if you clean , dissembled , and reassembled your heads.
Or
you can get a special tool ( a suction cup on the end of a stick ) and some lapping compound for $10 at most parts strores.

Answer 6

You can't do it.You will need a boring tool,lathe.flat grinders ect.

Answer 7

Get yourself a haynes manual it will help you through the rebulding process

Answer 8

the amount you would have to spend on tools would be way more than having them done , sorry.