Cylinder Head questions

[farmerfred]

I think that my truck may have worn valve guides and a rounded cam lobe (or two). I need to check into things some more, but I thought I'd ask your advice about what I plan to do if these things do need to be replaced.

I am thinking about getting a setting of complete cylinder heads rather than take the heads to a machine shop. I don't think that I have the knowledge and skill to inspect the valves, etc. I also don't know of a good machine shop around here, and then there's the hassle of not being able to use the truck while the heads are in the shop. I do want to learn something and do some of it myself. After reading the Haynes manual, I think replacing the heads and cam are right at my skill level.

The truck is a stock 350 (except for an HEI distributor). I'd like to keep it stock. Autozone has reman. heads for $180 each. Napa has them for $240 each. Anyone have any experience with either of these? Also, am I right in thinking that a "cylinder head assembly" is a straightforward install? Any thoughts would be appreciated!

[clay68c10]

You could get some new vortech heads and aluminum intake with a mild cam for not much more $. It's a good power upgrade and easy to install stock GM parts. It would all bolt up to your stock short block and if you want to build for something more later, you'd be one step ahead. You could probably get a couple of bucks for your old heads to offset the cost also.

[Myself]

Ask for replacement heads for a 73-78 Z-28 Camaro. They'll give you better power and performance, and probably around the same price reman.

[69rut]

I would check the re-built heads to be sure thay have the same casting numbers as the ones you trade in. The heads are all interchangable, but not all alike.

You may also want to find a good shop to check the engine condition before you buy too much. If the cam is worn, chances are the rings and bearings may be too. Putting on re-built heads may help some, but might expose other problems. Same with the cam. The new parts will out perform the old and may lead to more problems.

Have a compression test and leak down test done. This will tell you if the rings or guides are bad.

[bryanw1968]

Originally Posted by 69rut

I would check the re-built heads to be sure thay have the same casting numbers as the ones you trade in. The heads are all interchangable, but not all alike.

You may also want to find a good shop to check the engine condition before you buy too much. If the cam is worn, chances are the rings and bearings may be too. Putting on re-built heads may help some, but might expose other problems. Same with the cam. The new parts will out perform the old and may lead to more problems.

Have a compression test and leak down test done. This will tell you if the rings or guides are bad.

I agree on this one. If the bottom end is in need and your budget allows you might as well throw some rings and bearings at it. "If" you need to.

As far as heads go, I'm not sure about what's availabe at the local parts house or how good they actually are. I do know that summit and jegs both have very reasonable prices on completely assembled heads and would cost less than having a machinist re-do yours. You might check ebay also. I just bought a set of trick flows on ebay for 1/2 the price and I'm completely happy with them.

[piecesparts]

FIRST and foremost, How many miles on the motor? If the motor is showing wear and tear on the valve guides, then changing the heads will tighten that end up, BUT the older rings on the pistons will probably suffer from the change and then you will use oil through them. I agree with the discussion on the Vortech heads and that they build good power. They are relatively easy to get, however, you have to get the intake also.

[farmerfred]

Thanks, everyone. The lower end comments make sense. I'm glad I asked. This is turning out to be quite a project!

I'm going to check summit and jegs more carefully. When I looked last night, I didn't see anything for someone who wants to keep it stock and simple.

Piecesparts: the odometer reads almost 68K. I've had the truck for almost 1 year. I'm guessing it's 168K.

[piecesparts]

Experience tells me, that if you go to tight on the top end, the motor will run and function, but a ring job would be desired at the same time.

[farmerfred]

Thanks, Piecesparts. I took a look at the manual, and it looks like doing the rings is a pretty big jump in the skill required. Seems to me--and tell me if I'm wrong--that if I'm going to have to pay someone to do the rings, I might as well buy a crate engine.

[qksilver]

Would getting a good used motor fit with your plan? Then you could over a period of time go thru the other engine and do a little hopping up. When you look in the back of Car Craft etc, they offer iron GM heads for around 325 a set or the vortec for more. There are a lot of options out there, carefull shopping.
Putting a redone set of heads on an engine that is worn out or close to it isn't a good investment.
If you put redone heads, then a ring job (probably new pistons) then the machine work then new cam, lifters, timing set, then might as well go ahead and do the bearings , oil pump and on and on.......

[farmerfred]

I hadn't really thought about this. The truck is a daily driver, and the cheapest crate engine would equal what I paid for the truck. I hadn't thought about a good used motor, if I could find one. That's a good idea. Of course I could luck out and the compression test could show that I don't need new rings.

[Huck]

Nine out of ten times I slap on rebuilt heads, the lower end starts blowing oil to the tune of a quart every couple of hundred miles if I'm lucky. You can probably pick up a used "guaranteed good" 350 from a junk yard for around $3-400. That just might be an easier solution to a daily driver. A factory crate motor is around $13-1400. with a 3yr 50K mile guarantee. If the truck gives out, just pull the crate motor back out for future use. Rebuilding these days is not really cost effective unless you know what your are doing, have the right tools, experience, time, etc. My .02

[farmerfred]

Thanks, Huck. I didn't think about either possibility. The idea of putting in a crate motor with the idea that I could always remove it later seems really smart, at least for someone like me who can follow directions but isn't skilled. I also didn't know that junkyards sold guaranteed good motors. I'll have to see if the ones around here (SW Ohio) do that.

[mrein3]

I look at it this way. If you know you need heads and a cam and you're not sure of the bottom end, all you'd be throwing away is the cam.

The last set of heads I had rebuilt were $125/side. That includes hardened seats and "bronzwal" (sp?). I'm not sure how to spell it but they put bronze inserts in because of the angle of the push rods. I guess BOP guys don't really need to do this. (I don't know heads and don't claim to know the first thing about what the machine shop guy does.)

Anyways you put $250 into the heads, $150 - $200 into a cam and give it a whirl. If it blows a bunch of smoke around the rings, save up for a short block then reuse your refreshed heads on that engine.

Sort of a pay as you go type of approach.

[farmerfred]

Originally Posted by mrein3

Anyways you put $250 into the heads, $150 - $200 into a cam and give it a whirl. If it blows a bunch of smoke around the rings, save up for a short block then reuse your refreshed heads on that engine.

Sort of a pay as you go type of approach.

I like this idea, but the short blocks I found at Jegs cost more than an entire crate engine. I'm sure they would be a serious upgrade, but I'm not looking for that. I've looked at a few other places, and it seems like short blocks are generally more upscale than I'd want to go. Are there stock short blocks available from reliable sources?

[Aarons72s]

You can get a stock short block, new, from gm for about 1,035.00! I asked the same question earlier. It is gm's basic crate 350 but without cam, timing chain, heads, oil pump and oil pan. Here is a link to the thread.
http://67-72chevytrucks.com/vboard/s...d.php?t=211790

[farmerfred]

Thanks, Aaron. Did you actually order one yet? I copied the part # from the Pace site. Neither the GMGoodwrench nor the Jegs sites have it.

[Aarons72s]

No not yet. Dont have the money. But I was curious if one was avaliable. I wiil be needing one probably in the next 2 years and I wanted to see what my options were. I dont know why finding stock short blocks are so hard to find. Because alot of us are using old or performance cylinder heads or want our own cam. I am just trying to cover all avaliable options so when I do buy I will have made the most informed decision. Take the part number down to your local favorite gm dealer and see if they will get you one but check on the price. Some dealers want to charge more, some times alot more, so be careful. At least from what i have read.

Here try this site: http://www.gmpartsdirect.com/

[farmerfred]

Maybe the price difference between the short and long stock blocks was so small that the shorts didn't sell. Thanks for the links.

[farmerfred]

I had the truck checked out by a mechanic today. He said the valve guides are worn. He also said that the compression was good. I didn't press him for numbers 'cause he didn't charge me. So is there any problem with just replacing the heads? I know that in the long run it would be best to put in a crate engine, but I'm not certain that I'll have the truck for much more than a year. If I replace the heads, do I need to replace the camshaft, too?

[Psycho71]

You might also see what a long block motor costs from a local rebuilder. A rebuilt longblock would be ALOT cheaper than a "crate" motor from Jegs or Summit, or GM for that matter. The long, and short blocks sold by these two are typically performance, if not full race quality stuff. A stock motor doesn't require all of the extras those motors have. A local rebuilder would charge you a core charge, but you should be able to bring yours in for the refund after the swap. A rebuilt long block should run you about 700-1000 bucks, and it would bring the skill level back to what you sound confident doing.

If I had to put heads on my motor, I'd do the lower end too. But that's me, and my truck. Putting a good set of heads, and a new cam, on might fix your troubles. But like said by others, it could show some weak parts in the lower end.

Jay

[piecesparts]

There is never anything wrong with just replacing the valve guides or replacing the heads, BUT just keep in mind that if you start or continue to use oil the cause could be attributed to the tighter top end. Your mileage on the motor is just a hint that there has to be some wear in that area.