Alright I just need suggestions, thoughts, and all that other stuff that comes with forums.

I am taking a 350 out of a '91 Chevy Silverado. I am going to tear it down and essentially re-manufacture it and put it in my '86 Camaro. I don't plan on making it a super race motor. I just want to put mostly stock parts back into the motor depending on prices, but I am planning on getting a bigger cam, an intake manifold, a carburetor set up, and headers.

Give me any pros, cons, suggestions, recommendations, remarks, or anything that comes to mind.

Thanks!

****EDIT**** 10/18/2010

From reading all the responses so far I will change what I want or just condense all the info.

I want to run on pump gas. Preferably not the highest octane. But if I keep the top end from the 305 my compression will go up. And to lower this I would need to bore out the cylinders (which wouldn't I need bigger pistons then?) but that would actually work because I would need to get pistons with valve reliefs on them (no idea what those are). And if I got new pistons I am assuming I would have to get new rods?

And another thing can someone give me an estimate of cost? Here is what I am doing so far...
Cam(mild), lifters ect, pistons with valve reliefs, rods, and getting the cylinders bored out.

If I missed anything that would have to also be done just let me know.

 

Pro: Should be a decent shortblock to build up.

Con: Heads are crap.

Pro: Your '86 305 heads would work well on the 350 shortblock. They'd work better with 1.94" intake valves and some port/bowl clean-up. They will need new valve springs if you want to use an aftermarket cam. Cutting the tops of the valve guides for positive-type valve stem seals would give you better seals and more valve lift capability.

If your '86 has a factory carb, keep it.

 

The 305 isn't carbed. It is TPI.

 

Any reason not to keep it TPI?

 

TPI is an excellent choice for a mild street-driven 350. I would keep it if you already have it.

 

Well I have done research on this before and I have posted on here.

Reasons to keep: I have it and I won't have to buy a carb.

Reasons to ditch it: The TPI wouldn't go onto the 350, I would have to get a new intake manifold (which would happen anyways), for the bigger cam I would have to get the computer adjusted, and people have just said carb is better.

I am just going from what people are saying. If keeping it TPI is cheaper and better, then hell yea I am going to do it, but opinions are different. If I get hard facts on something then that's what I will choose.

This is where I need the suggestions. I don't care if it's TPI or Carbed. I think Carbed would sound better and just has that classic touch to it, but I am a very persuadable guy and if people say TPI is better and have reasons then that's awesome.

 

So does the camaro have the computer in it still? or has it been guted? are you going to keep it if it is still in it? because if you are you will still need to burn a chip for it to help the 350 run, and if you are going to do that then keep the TPI, after all good milage is still important.

 

I already addressed that:

Since the TPI bolts to the heads, putting your 305 heads on the 350 would solve that problem. Of course, if you want performance improvements over the stock TPI hardware, you may go for a different intake, but then the other statement about the truck 350 still applies:
In which case, you're still either going to use the 305 heads, or get something better.

For a "mild 350", though, the 305 heads, with the mods already suggested, would be fine - even with the stock TPI hardware.

'86 TPI is MAF, which is much more tolerant of displacement changes than SD.

 

The computer is still in the Camaro. Everything is in it still, I am currently driving it.

 

For the bigger cam at this time I don't plan on putting the biggest one in it, just something bigger. And yes all I want is a "mild 350" right now.

So from what I am getting from this, I can take the top part of my 305 and throw that right onto the 350 and I will be good to go on that?

 

Yes except for the cam, that would be a big step down. The heads from a 305 will give you mre compression, thats both good and bad. As for the computer, go to that section of the boards and you will find all the info you will need.

 

What do you mean by that?

 

I mean dont use the cam from the 305 in a 350, it will more than likely be a smaller cam, lift and duration wise. There are many cams on the market that can be had for 100.00 dollars and up for a 350 that can still be run with the computer.
Here go to this site, it have all the info for 3rd gens, as far as cam size, and other info.
http://www.f-body.org/tech/tech.htm#ThirdGen

from here you will see that cam size changed from a 305 to a 350.

 

The 350 is coming from a truck, not a 3rd gen. The stated intent was to get a different cam.

 

Yes I get that, but I still need to finish my thought. And still the cam from a 305 is different than a 350 in most but not all cases.

 

There were different cams for different 305's. So what? If you're getting an aftermarket cam, factory cams are moot.

 

He asked about swaping just the top end of the motor and that it would be good to go, I said yes, as long as he didnt use the 305 cam, thats so what. It was based on my assumtion that he was going to use the whole topend including the cam, I did a misread on the cam part. Moot point yes, but still true.

 

Yea sorry for the confusion. No matter what I plan on getting the biggest cam I can without having to send the computer in to get changed or whatever.

There is about maybe 100k miles on the 350, should I get new crank shaft, rods, pistons, and all that jazz? If so, would I have to get the engine balanced?

 

No you dont need a new crank and rods, unless they are bent or cracked if you are willing to pay the money you can have them magna-flux them and check the main and rod jurnals as well as the ends of the rods just to be sure they dont need to be resized, and because the crank is out get it polished. As for pistons, that all depends on how bad the cylinders are, if they say it needs to be bored foind out how much, I would guess that no matter what 0.30 over unless they are so bad they need to take more off. As for balance, that can cost some money, so that all depends on what you really want to spend. Do you have to? no. And even with a new crank and rods you shouldnt have to. Now back to the cam, there are many grinds that you can get that will work with the computer, The best bet is to call a cam maker and ask them, tell them what you want to do with the car, you could ask people here but I would say that 15 people will tell you 15 things. So ask the cam company, just because a cam worked for this persons setup it may not work with yours.

 

The thing that Computers have a problem with about performance cams is the Lobe Separation Angle. If you keep the LSA at 112-114, you should be alright. Any less and you'll have too little vacuum at idle and the computer will try to fix it.

 

So true. Computer-controlled cars rely on MAP, MAF, and several other sensors that are easily messed up with lumpy cams. The main difference between "computer" cams and regular cams is that they typically have a wider LSA and careful use of duration to make sure the vacuum signal is steady enough for the computer to operate the engine.

It doesn't matter as much with a carb; when the carb gets a vacuum pulse it pulls in some fuel, but the computer (and knock sensors if equipped) get very easily fooled with a cam that's too lumpy.

 

Alright sweet. I don't want to put a crap ton of money into the car yet. Funds are not that abundant at the time. I just mainly want to get the 350 in the camaro and not worry about it after that too much. I would say in about 6 years i will go all out on it, but until then minimal cost is needed.

 

I have been told that putting the heads from the 305 on to the 350 will not work because they will be too small. Is this true?

 

No.

 

No it is not true. You will however go up in compression, as an example you could go from say 9.0 to 1 up to 10.0 to1. That can make it hard to run pump gas even the high octane stuff. But that all depends on the pistons you use as well as how thick the head gaskets are.

 

Well what would you recommend then? I still want to use pump gas.

 

Well if you are going to do a full rebuild you can get pistons with valve reliefs on them, they will either have 2 or 4. On the last 350 I built with 305 heads it had 4 on the tops of the pistons I still had 185-190 psi on each cylinder and ended up with about 9.5:1 compression, so I could run pump gas with a holley on top of a stock intake. So thats what I would do. And I had a very mild (RV)cam in it.
Another thing is, if you have the block bored out that will lower the compression a little. And you can get a little thicker head gasket as far as compressed thickness goes.

 

With the proper camshaft, you can still use pump gas just fine. It will have to be premium fuel, but still just pump gas. I had 305 heads on a 350 and it worked just fine on 91 octane.

 

What does the octane rating even have to do with the compression?

 

Octane is essentially a gasoline stabilizer. When you compress gasoline to a certain pressure, it will combust with or without spark. This is called pre-ignition or detonation and it's bad for your Pistons. It also robs your engine of power because the pistons will be working against themselves. The more octane there is, the more the fuel can be compressed without detonation. This is why racers use Alcohol. You can compress that further without detonation and it burns cleaner and more efficiently. So, if you build a High Compression engine, Octane is VERY important.

 

Higher octane gasoline is harder to ignite, and burns more slowly than low octane gasoline, and because of that they are less prone to detonation/spark knock.

High compression ratios create more heat than low compression ratios (The more you compress a gas, the more heat is created) and too much compression can create enough heat to ignite gasoline without a spark. The higher the octane rating is, the more resistant the gasoline is to this. This is why high compression engines need to use high octane gasoline.

This is an extremely "cliff notes" explaination, but accurate.

 

I edited my original post to compensate for the new info and responses. Check it out please.

 

If you have to bore the block anyway, you lower compression by using a dished piston, instead of one with a flat face (either style will have valve reliefs). If you want to use 87 octane fuel, you'll probably have to stay between 9:1 and 9.5:1 compression ratio, and use the proper sized camshaft to match that.

You don't have to get new rods when you change pistons. There is a wrist pin that holds the piston onto the rod that the machine shop can remove, and then install your new pistons on those rods. They will also probably want to put new rod bolts into the rods, and resize the big end of the rods, which is basically boring them out to make sure they are perfectly round. No need to buy new rods.

If your 350 block has been machined for roller lifters (some truck engines were, some were not) then you should use a hydraulic roller cam setup, with factory style roller lifters and retainer plate, like the 305/350 TPI engines used. Its the same block that the 350 TPI had.

 

This seems like a lot of work. Sounds like I would have to take it to a shop for most of this stuff anyways. Wouldn't they check the compression and if it's machined for roller lifters and such?

Also, couldn't I use the trucks VIN to figure out if it's machined for roller lifters?

 

The VIN won't tell you squat about the block. It will tell you what year the truck was, but it won't tell you what block you've got. Get the block casting # - that tells you as much as you can possibly know from factory numbers. But, the same casting # blocks were used for passenger cars (with roller lifters), trucks (did not have roller lifters), crate engines (such as the famed ZZ4), could have 2-bolt mains, could have 4-bolt mains, were machined for roller lifters, were not machined for roller lifters - you can't tell any of that from the casting #. The VIN stamped on the block may give you a hint (passenger vs truck), but it's just as easy to look at the lifter valley and remove all doubt.

 

Ok. Thanks.

 

No, "Octane is a hydrocarbon and an alkane with the chemical formula CH3(CH2)6CH3." (Wikipedia)

Octane rating "is a measure for the anti-knocking properties of gasoline". (ibid)

I'm sure you can Google it and get some learnin' for yourself.