TZFBird

Alright, I am planning on an engine rebuild sometime in the future. I want to add an LT1 cam, Vortec heads, Vortec intake, and do a lot of work to the TBI(ultimate mods, TPI throttle blades, AFPR, etc.) and 3" exhaust.
Anyway, I was telling a mechanic about doing this stuff and he said I will need to rebuild the bottom end as well, I.E. crank, pistons.
My question is.....Do I really need to do this? I know it could help a lot, but I'm not sure. I've never done any of this before.

Oh, I have a pretty much stock LO3 right now.

Ukraine Train

the mechanic's wrong. the mods you're talking are fairly mild and don't warrant a new bottom end. the lt1 cam and vortec heads were used on stock engines that, as far as i know, didn't have forged anything from the factory

my suggestion is do a lot of reading before you start doing any work, it'll save you a lot of headaches

RB83L69

What you're talking about is not a "rebuild". It's a list of modifications. What your mechanic is talking about is an actual rebuild, but no mods.

You could do the mods you mention to an existing motor, if its bottom end (crank, pistons, bearings, rings) is in good condition. There is no rule that says when you have to rebuild the short block when doing top-end mods, although if you get him to do all the top-end stuff but not the bottom end and the engine blows up, he will certainly not warranty it. Rebuilding the bottom end won't do anything for power if it's in good shape now, but might make it last a whole lot longer.

Of course, if it burns oil or has rods knocking, then it's fairly pointless to do any mods without repairing the short block first.

89WS-6

I think he's wrong. Unless they are damaged, or show significant signs of wearing the will be ok. Now seals, bearings, stuff like that could always use a replacement.

TZFBird

I am going to rebuild it at the same time as add these mods. I didn't know you replaced pistons, and crank with a rebuild. I thought you just go through and replace all seals, and whatnot in the heads, along with new rings, and other things that wear over time.
So a complete rebuild would includeand not be limited to)
Crank, rods, pistons, rings, bearings, timing chain, and gaskets. and other misc. items?

I thought it was all of the above and I could keep the stock rods, crank and pistons. But I don't know. This is the first time I will be doing this. I will also be trying to do all the work myself.

Oh, by the way, there are rebuild kits in the Summit catalog for a 1976-1993 Chevy 305. It has everything but the rods and crank. They list 2 types. Forged and Hypereutectic. Which do I use? I am guessing the hyper one.

I guess I could get a rebuild kit from a local auto parts store, but I just want to know what I need to get.

Thanks

RB83L69

In a typical rebuild, you bore the block, which means you need new pistons since the old ones won't fit tightly any more. You probably wouldn't need a new crank or new rods, although you might replace them. You would generally get the crank turned, and maybe put new bolts in the rods and have them reconditioned.

So, your "complete rebuild" description is reasonably accurate. You probably would want the hyper pistons if you went the kit route which is not a bad idea - it's usually cheaper to get the parts that way than it is to buy them each separately.

You will probably find that you will spend more on machine work and assembly labor than on the parts, by far. Maybe twice as much. If you want to do the assembly yourself and this is your first time assembling a short block, you will need several specialty tools, and it would be wise to have somebody around that has some experience. But it's not brain surgery or anything, just good insurance against doing something that will cost you money later.

five7kid

iTrader: (14)

Just don't do all this to a 305. Spending the machining and lower end parts money just doesn't make $'s/HP sense. Find a builder 350 block and work on it. You'll be much happier with the results.

I also still don't get the attaction to Vortec heads. If you don't yet get Chevy High Performance magazine, pick up the latest copy. In it, they describe what you have to do to those heads to use more than .420" lift at the valve. Perhaps not too big a deal if you do it all yourself, but paying a machine shop to do it will run you more than buying real aftermarket performance heads that have all those features and are better castings; and have the exhaust cross-over passage for the EGR and take "normal" intake manifolds to boot.

If you still think you want Vortec heads on a 305, you'll need to shave them to reduce the chambers down to 58cc. No need to shave them if on a 350.

I'm racking my brain trying to remember the name of the machine shop I went to in Lincoln, but it's been over 16 years now. I think it was somewhere north/central, but that's the best I can do. They did excellent work.

It's a good idea to have the engine at the machine shop before ordering a kit, as they can tell you if you need over/under sized parts, and which sizes you'll need. Sometimes, they can even get it all for you at a lower price than getting the parts someplace else.

TZFBird

Well, I don't know. I guess I could start looking for an old 350 block. Maybe one for $250 or less. Then I would be breaking even on the machine work I would need for the heads on the 305. Well, I guess I will start searching for the 350, and if I get lucky and find one, I could just buy all my parts then.
I am doing a lot of driving and getting really bad gas mileage right now. Don't know what is wrong. I use almost a 1/4 tank going to work and back! It's even all highway miles! Is a 350 that bad? I am estimateing it somewhere around 30 miles each way maybe. It's either horrible mileage, or else the guage is screwed up.

egmonster

Sounds like you're running really rich... You might want to replace your O2 sensor. That could be the culprit, although bad plugs, something blocking your air intake, loss of vacuum amongst other things could all be culprits. You shouldn't have a problem finding a decent 350 block. Go to motec.com and do a search, they have all the casting #'s etc. Some GM blocks came with forged cranks and rods already and you might be able to save some money by reusing them. They are not the highest quality forged peices but they are still pretty good. Also get forged stuff, not hyper. It's much much stronger and will last longer. It's lighter too....

jeffs82z28

Don't get the forged pistons unless you plan to really zing the motor, they are for racing applications.
Hyper-eutectic pistons will do everything you want them to do in a daily driver.

TZFBird

Well, I don't think I am running too rich. I cheched the plugs on the driver's side and they were whitish. I also got in this morning to go to work and the guage went back up to almost full. So I don't think there is anything wrong. It might be a tad lean, but not enough to cause any noticable sign of being lean such as dying, or lack of power.

Also, I have read a few posts and have come to the conclusion that I could just spend another $200 or so and get a 350 to rebuild. I will get more power, possibly better gas mileage if tuned right, and don't have to hear the phrase "no replacement for displacement" any longer. I would really like a 350, but the problem is finding one. Will my mods listed above work in a 350? I know all of them will, but I am a little leary of the cam. Is an LT1 better than a stock 350 cam? I know it would be better than a cam out of a really old 350 possibly, but who knows. Is there a way to check the cam specs without taking it somewhere?

Thanks

robertg

iTrader: (2)

If you're going for high performance (300 horse and up) get forged or hypereutectics.

If you ever plan on running nitrous or a turbo/supercharger, get forged pistons.

If you're doing a basic rebuild with not too-high performance (Like I did with my 305), you can get away with cast pistons.

And please, do not give me any flak for choosing to build a 305.

jeffs82z28

FLAK FLAK FLAK FLACK FLAK

J/K couldn't resist

custman87T/A

I am using the vortec heads (062 casting)on the rebuild of .030 350 in the vette. It was not a big deal for the machine shop to cut the guides and install screw in studs. I supplied the parts and he did the work for $175 and I paid $200 for the brand new casting.
The machinist LOVED the Vortecs, he was porting a set of L98s at the time I brought the Vortecs to him and he perfered these heads over the ported L98 right out of the box. The only thing to consider with the Vortec is to bring the comp. ratio down. They are 64cc heads but he measured 61cc.
How can you beat a stock head that flows really well and should prove to be extremely reliable.