shaynecastongua

iTrader: (1)

Hey guys I've had a mystery 350 sitting in my garage for the past 2 years and I'm looking for some help identifying exactly what I have here. The casting number is 3970014, I was told that it "probably" came out of a 72' blazer by the PO (the numbers make sense for that). I was going to pull everything apart and see if it's worth reworking/rebuilding. What are some key dimensions that I should check? I'm thinking cylinder bore size and roundness, for starters. Will there be searchable part numbers on the cam, crank, and rods?

AlkyIROC

Get the suffix code off the block. It will be a bunch of numbers stamped into the deck surface in front of the right hand head.

If you're going to pull it apart and rebuilt it then what it came out of really means nothing. It will be just another 350.

shaynecastongua

iTrader: (1)

I don't see anything but the 3970014 number in front of the deck. I guess what I meant to say what should I check to see if it's usable as is? I know that's not even close to an exact science, but all of the bores look suspiciously smooth and clean (like they've been recently machined) and none of the pistons look especially worn.

KCG

iTrader: (1)

Are the rod/caps numbered?

shaynecastongua

iTrader: (1)

Caps say GM14 and 3951

Rods are not labelled except for cylinder number stamped on them

Crank stamped 3932442

Drew

iTrader: (58)

Mortec.com Check it out.

midias

70-76 2 or 4 bolt main block. A standard non roller 350. Rebuild how you want and add a roller cam.

shaynecastongua

iTrader: (1)

Thanks!

sofakingdom

iTrader: (1)

Yup, just yerbasic 70s 350 block.

442 is yerbasic cast 350 crank.

Pay careful attention to it before spending money on it, and make sure it doesn't have any of The Problems that were so common in the 70s.

• Starter bolt holes drilled too far from the crankshaft centerline - makes it crank slow, make that horrible grinding noise you can hear from a half-mile away, and EAT flex plates and starter drives
• Lifter bores that don't point straight at the cam lobes - makes it EAT cams and lifters, always the same lobes, no matter what you do
• Bell housing dowel pins not centered on the crank - makes it EAT pump bushings in automatic transmissions
• Cylinders not pointed perpendicular to the crank (tilted in the front-rear axis) - makes it EAT rods on the sides, and their bearings; and makes the engine make just a whole lot of general low-grade indistinct grinding gnashing unhappy sounds from the oil pan and produce even less power than it otherwise would
• Head dowel pins not centered on the deck - makes it IMPOSSIBLE to ever get an intake to seal

There are others but those are the most common ones. Virtually every 70s block has AT LEAST one of them and often multiple. As an example, I have a 74 454 that has both the starter bolt hole one and the BH dowel pin one. Original motor to the car, still in it.

My advice remains, go get a 96-2000 core from the junkyard and build that, and throw all that other old crap in the trash. Sure, it seems like a phenomenal waste of money to pay $200 or whatever for another core when you already have these "free" ones; but when you put $1500 worth of machine work and parts into one only to discover that it's a worthless pile of horse exhaust, the price of that core starts looking MIGHTY CHEEEEEEEP by comparison to throwing all THAT in the trash ALONG WITH THE "FREE" BLOCK and starting over. Plus, you need heads anyway, and that core is the best way to get them. Might as well accept the FREE block that you'll get with the heads you buy, that will ALREADY come equipped with the roller setup, and build that instead of taking chances on that 70s garbage.

midias

Another thing to consider is a 96-2000 core will probably save you a good $300 on the roller cam conversion because it is already setup for it.

shaynecastongua

iTrader: (1)

Good to know. I wasn't around in the 70s (or 80s for that matter), so I had no context about how good these blocks were. I appreciate the insight, and will continue to search for a feasible block. Thanks guys!

midias

Go to a junkyard or look online and find a 96 through 2000 Chevy 350 it will have vortec heads never ever use the word Vortec when you're at a junkyard just tell them 98 Chevy 350 if they try and give you somebody else not 96 through 2000 tell them yours looks different and you want a 98. Take the heads off have them refreshed at a machine shop put new Springs on them roller cam of your choice and have a decent motor

shaynecastongua

iTrader: (1)

I'll do that. Thanks for the advice.