I’m planning on buying a new (1969), bored out block to install in my 1977 corvette. The block is completely bare and stand alone; I was wondering, since the block is bored out to .030 would I have to modify my heads in any way or would I have to get a different head gasket to accommodate to the larger cylinders and pistons? I plan to use my stock L48 heads but if that’ll be an issue I’ll look for different heads. Also, where would be some good places to buy new valve train components and oversized rotating assembly parts? I’d like for the internals to be able to hold up to some boost pressure although I’m not planning on boosting it anytime soon, if at all. I’m not planning at hp chasing but an increase from the stock 180hp would be pretty awesome. Oh yeah I forgot, a camshaft, since I’m trying to build this from the naked block I should probably get a better cam but I don’t want anything with crazy chop that’ll only turn my gas into noise or stall at red lights. My overall plan is a fun, sporty car that is quick on the uptake and won’t kill me as soon as I press the gas. This is my first time doing major engine work so any tips, tricks, or recommendations are greatly appreciated!

 

Before you do anything else, you should find a metal recycling dumpster and pitch your L48 heads inside.

Don't waste any time or money on them. They were trash new, and are trash now.

 

thanks! What heads should I look for? I’m on a budget so I don’t want to break the bank on heads if it won’t make much of a difference. Any brands in particular to look for or to stay away from?

 

Beware of buying a bored block unless it has been honed to final size and includes a set of fitted pistons and a seller who's willing to demonstrate that the pistons have the proper clearance. Assuming this is a 350 block, a nominal .030 bore would measure 4.030". In reality, you would bore about .004-.005 undersize and hone to the finished size. The finished size would be determined by checking the diameter of each piston at the specified measuring location which is typically at the skirt and 90* to the pin, and honing the hole for that piston to a diameter that provides the required clearance.

For example, if you use hypereutectic pistons, the required clearance would be .0015 to .002. If you purchase a bored and honed block finished to 4.030", then you have to find pistons that measure 4.028 to 4.0285. That's going about it backward and not something you want to do. OTOH, if this bored block has been left with a honing allowance, then you'll need about a thousand dollars worth of Sunnen rigid hone and stones plus another $300 or so for a tenth reading dial bore gauge for checking size, and then you can fit the pistons yourself.

IMO, if you're truly looking at a bare 30 over block without fitted pistons, you'd be far better off to find a block with a standard but worn bore and have a machine shop bore and hone it to fit the pistons of your choice. For that matter, why not use your existing engine for the rebuild. Starting with nothing but a block and piecing an engine together is about as expensive a path to building an engine as I can imagine.

 

the only reason I do not want to use my existing block is because it’s a 2 bolt main. Everything I’ve hear is how the 2 bolt main 350s can’t hold any power above stock. Also the other reason is that I want the L48 as a backup since it’s the stock engine. Let’s say I wanted to sell it, having the stock parts along with the modified parts should help with selling it.

 

Nothing at all wrong with a 2 bolt main block Mate.
You can build a 450HP street engine around that with no issues whatsoever. It can be drilled to a 4 bolt splayed fashion that is even stronger than a factory 4 bolt. The weak link here isn't your block.
A lot of people will say, Gotta have a 4 bolt main block, just gotta have it. It's just bragging rights below 500 HP.
A block that's already been bored? To what? As stated above. If finished it had better include the pistons it was fitted to. I usually go about .002 under. Then I only need to hone .003 -.004 to get my clearance.
None the less. The L48 crank isn't the best. But most likely fine up to 400HP. Basically the same with the rods.
Your L48 heads are boat anchors at best. Nothing there at all.
Me, I'd build the block you have.
No body wants to buy a car and be told they can swap the engine if they want numbers matching, Nobody!
Nobody wants to store a engine indefinitely just in case. (As it slowly rusts away).
It's a 77. There never going to be the cream of the crop.
Think about it.

 

I just read your other, same thread in the other column. Gezzz Mate. That sucks!
Anyway, about 9,000 threads on this forum over the last 20 years on this very topic.
Cheap aluminium heads. Decent intake manifold, headers with a good 2 1/2 inch true dual exhaust. Comp cams 268 grind cam. Hyper flat top pistons. Really good recurve on your distributor or purchase a DUI Distributor setup for your car.
BAM! 350HP.

 

OP has started a thread on the C3 Tech/Perf section. This thread will be closed as a cross thread.