[grandprix601]

Hi I have a 350 vortec shortblock that I will be sending to the machine shop. The block has pistons already in it that have .60 stamped on them the pistons also seem to have the center of the piston shaved..does the stock vortec pistons come like that?? The block also includes the crank and rods.

This is actually my 2nd rebuild the first build was a v6 turbo but it was basically stock as I started to fool around with the buick I learned that when u change the camshaft u have to get the pistons shaved for piston valve clearance does this apply to the 350 vortec?

Also I was wanting to know where can u purchase timing chain tensioners..for the 350 vortec???

Also I have 350 96 vortec heads that do not have springs or valves...what do you guys suggest for valves and springs???

Im trying to maybe get 325+...but I want it to be street legal

[techinspector1]

Originally Posted by grandprix601

Hi I have a 350 vortec shortblock that I will be sending to the machine shop. The block has pistons already in it that have .60 stamped on them the pistons also seem to have the center of the piston shaved..does the stock vortec pistons come like that?? The block also includes the crank and rods.

This is actually my 2nd rebuild the first build was a v6 turbo but it was basically stock as I started to fool around with the buick I learned that when u change the camshaft u have to get the pistons shaved for piston valve clearance does this apply to the 350 vortec?

Also I was wanting to know where can u purchase timing chain tensioners..for the 350 vortec???

Also I have 350 96 vortec heads that do not have springs or valves...what do you guys suggest for valves and springs???

Im trying to maybe get 325+...but I want it to be street legal

There are enough roller 5700 Vortec blocks in the boneyards for cheap by now that I would never begin a build with a block that was already 0.060"-overbored.

Not sure what you mean by the piston being "shaved". Usually, if you need more clearance between the piston and the valve, you will use a tool to cut pockets into the piston crown.

I'm not aware of any chain tensioner for the small block Chevy. If the chain is loose, a machinist may have align honed or align bored the block in the past (another reason to look for another block). When this is done, it moves the crankshaft closer to the camshaft in the block and causes excess slop in the chain. There are shorter chains available to take up the excess slack in motors where the block has been cut.

At the 325 hp level, you won't need anything more than stock components in the heads. Stock 1.94" intake valves, stock 1.50" exhaust valves, stock seals, stock retainers/keepers. Do a 3 or 5 angle valve job on the valves and seats and call it good. The stock Vortec heads are limited to valve lift of 0.450" with the stock valve/seal/retainer components, so choose a cam with 0.450" or less lift at the valve with 1.5:1 ratio stock rail rockers. I would build the motor at somewhere between 9.0:1 and 9.5:1 static compression ratio so that matching up a short cam with it will give you the correct cylinder pressure to use pump gas. Crane used to make a nice little cam that would work well....It was called the 266H10 Energizer. Specs were as follows....operating range 1400-5000 rpm's, advertised duration 266/266 degrees, duration @ 0.050" tappet lift 210/210 degrees, valve lift 0.440"/0.440", Lobe Separation Angle 110 degrees. This is a popular grind and most all cam grinders would be able to provide the same cam for you. This cam should work fine with a stock torque converter. Another, slightly hotter cam would also work, the 272H10 Energizer. Specs as follows....operating range 1600-5400 rpm's, advertised duration 272/272 degrees, duration @0.050" tappet lift 216/216 degrees, valve lift 0.454"/0.454", Lobe Separation Angle 110 degrees.

I would use a set of long-tube headers, 1 5/8" primary tube size, Edelbrock RPM Vortec or Weiand Stealth Vortec intake and a 600-650 carb.

[ap72]

i'd run a roller cam, it ends up costing the same at this level. about 215/215 on a 108lsa. will work with stock drivetrain. do the rest as already stated.

[cobalt327]

Originally Posted by grandprix601

Hi I have a 350 vortec shortblock that I will be sending to the machine shop. The block has pistons already in it that have .60 stamped on them the pistons also seem to have the center of the piston shaved..does the stock vortec pistons come like that??

Do you mean a dish?



If so, yeah, Vortec pistons are dished. The piston shown isn't a Vortec, Vortec pistons also have valve relief notches.

[techinspector1]

Originally Posted by ap72

i'd run a roller cam, it ends up costing the same at this level. about 215/215 on a 108lsa. will work with stock drivetrain. do the rest as already stated.

Thanks ap, I got so wrapped up in the specs that I forgot to include the basics. In this day and age, it makes no sense to use a flat tappet camshaft. You can find a hydraulic roller with the specs I listed.

[Rickracer]

There are lots of used LT1 roller cams for sale cheap, and they would work pretty well in a Vortec motor.

[grandprix601]

My eyes are getting bad LOL i took another look at the block 030 is stamped on the pistons...would it be a good idea to build this block up....

[SSedan64]

Originally Posted by grandprix601

My eyes are getting bad LOL i took another look at the block 030 is stamped on the pistons...would it be a good idea to build this block up....

Best way to tell is take it to a Shop & have it checked 1st. May only need to go to .040" overbore. Up to .060" should be fine for the HP your looking for but, as said have the cylinder walls Sonic checked for thickness + Block & Heads magged for cracks before you waste $$ on parts for it.

[cobalt327]

Originally Posted by grandprix601

Hi I have a 350 vortec shortblock that I will be sending to the machine shop. The block has pistons already in it

I hope you're removing the crank, rods, pistons, cam, etc. before taking it in- they charge $hop rate to do all the work you could do at home.

Is the ridge at the tops of the cylinders very pronounced? If your finger nail catches real easy on this ridge, it probably isn't going to clean up @ 0.040", and will need to go 60 over.

For all the cheap standard bore blocks out there, the better way might be to score one of them, and bypass paying for the sonic testing of a block that will then likely have to be taken to its max overbore of 0.060" (no rebuilding it later on down the road).

Just a thought...