Thread: 350 to 383 build 1981 Chevy Scottsdale k30

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Hey, I recently bought a 1981 Chevy k30 with as far as I know, an hd350 wondering what the difference was between a regular 350 and an hd350 if you guys know, as well in planning on building a 383 striker and was wondering if I bought the normal parts like the carb, cam, heads would they be interchangeable. I know the crank and pistons and what not would have to be different but I was wondering what I could use in the meantime on my truck.

Originally Posted by AustinMcGonegal

Hey, I recently bought a 1981 Chevy k30 with as far as I know, an hd350 wondering what the difference was between a regular 350 and an hd350 if you guys know, as well in planning on building a 383 stroker and was wondering if I bought the normal parts like the carb, cam, heads would they be interchangeable. I know the crank and pistons and what not would have to be different but I was wondering what I could use in the meantime on my truck.

First thing you need to do is find out what you have.....

The block casting number is at the rear of the block on the driver's side. It is normally all jammed up with dirt and oil, so you may need to use a mechanic's brush and some solvent to clean it so that you can read it....You may also need a strong flashlight and a telescoping mechanic's mirror. In extreme cases, you may need a sharp-pointed pick or awl to scratch away the foreign material that collects in between the numbers....the two most commonly mistaken numbers are 3 and 8, so make sure what you have and post it on here for us to see....
http://www.speednik.com/files/2013/0...asylum-com.jpg

The other identifier is stamped into the block deck surface at the front of the block on the passenger's side, just above the top water pump bolt head and is called a suffix number....
http://www.crankshaftcoalition.com/w...lock_codes.jpg

You want to know what block you have because it could be a 262, 265, 283, 305 or 307 block (all of which have a smaller bore than a 350 block) and you wouldn't want to plan on spending money on a stroker kit for one of those blocks. It could also turn out to be a 400 block that with a simple overbore and piston change, would make all the power you want.

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Like Techinspector says, you need to check and confirm the numbers. I've seen folks do some pretty "shady" things with Chevy small blocks, since from the outside, and without checking the numbers, you would be hard pressed to tell one from the other; there are some subtle distinctions, but unless you are a hardcore "Mouse Motor Freak", they would likely not be recognizable to you. If your truck is an original, unmolested one, again, hard to tell just by a casual look, that engine should be a 350 or a 400. I have owned a number of K20/K30 Chevys from 1978 to 1982, and they all had 400 CuIn. engines.

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Tech and Rrumbler are giving great info. Too many times I have parted 78-87 K30s and almost every time each one had a 305 in it. Seems like these trucks were always worked hard and people would just put what ever they could find back in them to keep getting more work out of them.

Welcome to CHR:

I love Chevy trucks -have a '71. This web site is a great reference to help you find out what you've got:

1973 - 1987 Chevy Truck Specs, Engines, transmissions, transfer cases, and rear ends, gear ratios - Chuck's Chevy Truck Pages

As others have said, you need to decipher the numbers on the engine as it may not be original. Round up the information and we'll look forward to lending a hand!

Glenn