First time engine rebuild

[theblindchicken]

The 350 in my '74 has been needing a rebuild for some time. She burns and leaks a good bit of oil, about 1 qt. every tank full and fouls the plugs with a month-ish. It's a California emissions engine, even though it has been long exempt from those restrictions. It was rebuilt back in the eighties by my father. I know many of yall have a lot more experience rebuilding these and I would appreciate any and all insight as to what im up against. Truck had ~76K miles when I startes driving her about 7 years ago. Probably close to 100K now (went through two odometers, both stopped working).

Problems:
Leaks and burns oil
Fouls plugs quickly
Needs a tune
"Dieseling" when hot
Hard to start when hot
Manifolds leaking and/or cracked

Current specs:
-350ci bored out .030 over and linebored.
-Isky cam (was rated for 11:1,unsure of numbers on it though)
-Stock heads (i believe 74cc)
-Quadrajet 4bbl
-Smog equipment removed and/or bypassed.
-Stock exhaust manifolds
-New high torque starter
-Stock oil pan
-Stock oil pump & pickup
-Points ign
-valve covers keep leaking a bit too.

Parts currently purchased:
-Gasket kit
-Thermostat
-Cast aluminum valve covers
-High volume, standard pressure oil pump & pickup


What im looking for:
Reliable engine that I dont have to check the oil every 3rd day and that will burn fuel cleanly.
Would like some power as well, but mainly focused on reliabilty at the moment and will change parts towards power later on.


Is there anything that is necessary to need before I crack it open and take a look? At the moment, its like a pandoras box. No idea if anything or everything needs to be replaced until its opened.

 

[likesoldtrucks]

I like the 350... new valve guides for unleaded fuel and you should have a good long lasting motor

 

[likesoldtrucks]

It must smoke like someone poured tranny fluid in the carb?

 

[Jrgunn5150]

Necessary? No, not at all.

You're absolutely correct, until you tear it down, there's no telling what it needs. If you want reliable and long lasting, I'd suggest planning on having it bored and honed.

Today's ring's and cylinder finishes are good nearly forever.

A mild cam, a set of Vortec head's, about 9:1 compression or so, and you should have a reliable, pump gas runner.

 

[theblindchicken]

I like the 350... new valve guides for unleaded fuel and you should have a good long lasting motor

I know for sure that at least some of the valve seals are leaking. Would it be more beneficial to look for a set of smaller cc heads versus rebuilding the large smoggers? I know this will increase the compression and create the need to run higher octane fuel, but wouldn't it produce more power compared to the larger volume due to the pressure difference?

It must smoke like someone poured tranny fluid in the carb?

Surprisingly, it doesn't smoke at all while driving. Only on start up does is smoke a bit, and that's probably from a combination of running rich as well as a buildup of oil.

Necessary? No, not at all.

You're absolutely correct, until you tear it down, there's no telling what it needs. If you want reliable and long lasting, I'd suggest planning on having it bored and honed.

Today's ring's and cylinder finishes are good nearly forever.

A mild cam, a set of Vortec head's, about 9:1 compression or so, and you should have a reliable, pump gas runner.

I've thought about a set of Vortec heads as well. What would be the advantage of running a set of vortecs over running another smaller cc head?

 

[Jrgunn5150]

Vortec's are dirt cheap, still. I think you can get a brand new set for around 500 bucks.

They are hands down the best SBC production head out there, better than Camel Humps, better than L98's, better than anything, by a fair margin. Simply in flow numbers they trounce everything else out there from the factory.

Also, with the really great chamber's they have, you can run up to 11:1 on Premium fuel, over 9:1 on the cheap stuff. They are also already set up with more modern, longer lasting seals and guides.

The downsides are, you need a dedicated intake to use the head's, which is around 200 bucks. You need matching centerbolt valvecover's, and the stock spring's liit your ultimate cam lift to under .450.

For a mild build though, they really are hard to beat. They easily support 400 HP as is, and without going to a head that's double or triple the cost, you're just not going to find a more effective head.

I certainly would not put a cent into the stock head's, not with Vortec's so cheap.

Do you have any idea how it was rebuilt back in the 80's? It may be overbored already.

 

[Georgeb]

I just priced up a rebuild of a stock 78 350 last fall. I was going to be into it for about the same price as a long block from summit. I would still rebuild just for the satisfaction of doing it myself. I can see you wanting to do it to. It's a good ecperience. Your 74 shouldn't have had that much on it for smog stuff. Did it have EGR? If not there is really no reason you couldnt use the heads and just have them freshened up. I would also love to bolt on some vortec heads but I can have my heads reworked for $75.00 each and still use my intake. I would call around to machine shops for an estimate. You are going to need to have them measure the cylinders to seee if they will be able to clean them up since it is already .030" over.

 

[theblindchicken]

In the first rebuild, the 350 was bored .030" over with pistons to match. In addition, it was line bored with a set of bearing and also got a new ISKY cam, but no idea what the numbers on that are.

Yes, it had an EGR on the passenger manifold. About last year, the original one finally cracked into 3 pieces (still laying around here somewhere i think) and the new one didn't come with the piping. So just blocked it off since the truck isn't required to be smog tested anymore.

 

[Jrgunn5150]

I would also love to bolt on some vortec heads but I can have my heads reworked for $75.00 each and still use my intake.

Yes, location is a factor, around me, all the machine shop's I trust to do it, put the cost of magnafluxing, squaring, valves, guides, etc, at around 175 per head, making Vortec's attractive to me.

If I could get it done for 75 each, I'd happily do it lol. Shop prices vary wildly, even over small geographic distances.

 

[DoubleDingo]

If you go with vortec heads, you also need self-aligning rockers. I learned it the hard way. The stock rockers will eventually rotate/walk off the valve stem.

 

[Jrgunn5150]

If you go with vortec heads, you also need self-aligning rockers. I learned it the hard way. The stock rockers will eventually rotate/walk off the valve stem.

Good call, that is true, they don't have to be full roller's, but they do have to be self aligning.

 

[Speakfordadead]

For 3k you can put a brand new crate motor in it. No fuss no muss. Its cheaper than a rebuild at your local Machine shop. Pull out the old and dunk in the new. If you don't have cash, put it on a card and make monthly payments. Cheaper than a new car and way more reliable. My .02

Sent from my LGLS991 using Tapatalk

 

[theblindchicken]

Thanks guys, really appreciate all the help and advice. Vortec heads are quite a few pennies out here in SoCal, but then again so is every other set of performance heads. Any cost that could be saved buying used heads would disappear as soon as theyre rebuilt and an intake is added.

Gotta save up some more cash and then find the time where I dont need the truck to crack her open and get it all done.

Got a little bit of a tick going on, is there an easy way to determine whether its a sticky lifter or one of the bearings?

 

[Jrgunn5150]

Thanks guys, really appreciate all the help and advice. Vortec heads are quite a few pennies out here in SoCal, but then again so is every other set of performance heads. Any cost that could be saved buying used heads would disappear as soon as theyre rebuilt and an intake is added.

Gotta save up some more cash and then find the time where I dont need the truck to crack her open and get it all done.

Got a little bit of a tick going on, is there an easy way to determine whether its a sticky lifter or one of the bearings?

Bearing's or rod's, bottom end noises, will occur in sync with engine speed. Lifter's, pushrods, etc, top end noises will happen at half engine speed.

I have no idea of the budget you are on, but these are the Vortecs that make me think they are such a screaming deal, http://www.summitracing.com/parts/s...-hMM0okNbRHyo5JqafJwf3ORBz1M-zQFauBoCdwbw_wcB

 

[theblindchicken]

Almost time to tear into it. Few more weeks and school will be done, then should easily hop on it.