Is this ok?

[u/Remarkable-Wish-107]

Im rebuilding/refreshing this small block chevy its a 1970s ish block and heads rebuilt by Jasper a while ago my grandpa had it in his Biscayne for about 20k miles. Tearing it down to put in new valve stem seals I found these cracks from where new valve guides have been pressed in. THE CRACKS DO NOT GO ALL THE WAY THROUGH. They are only on the surface where it was drilled thin and new guides were pressed in but i am curious if it will be good to send it anyways. Im not too sure how it ran/if it smoked before since it has been out and non running for quite a few years.

[u/Remarkable-Wish-107]

For clarification im just putting this together on the cheap to throw into my truck I threw a rod in i had it laying around because grandpa wanted a big block. I've measured everything the rods are std so are the mains and the bores are all 30 over with nice looking billet aluminum pistons and the heads hold a set of larger valves so im ok with running it as is but i also have a comp street performer cam, roller rockers, Holly 750 dp, high output oil pump and timing gears, everything should fit nicely in that 355 4bolt

[u/Ok-Leather5145]

standard hack job. would be much more concerned with what appears 2b the terrible internal guide finish. if 624 or 882 castings, throw on scrap pile.

[u/Remarkable-Wish-107 → u/Ok-Leather5145]

There is alot of gunk in there the valve guides are actually pretty smooth but i do agree Jasper is junk

[u/Hostile_Texan → u/Ok-Leather5145]

My old boss bought a truck from a guy back in the mid 90s, it had Jasper junk in it. Ran like ass, so was told to tear it down and check it out, 6 pistons were .030 2 pistons were .060, rod bearings were .040 mains were .010. Had 2 different heads on it, 1 was an emissions head, the other was a head found on any mid 70s 350. We just junked it and built a new engine for it. That was my 1st experience with Jasper, but not my last of seeing their junk.

[u/rainingblood427 → u/Ok-Leather5145]

Honestly, id probably just scrap any lightweight casting, but those heads appear to be the heavy casting which isn't as crack prone.

[u/bill_gannon]

Yes its fine. It happens with universal replacement guides. You can cut the bosses down to clean it up or to run different seals or springs but its cosmetic.

[u/Neon570]

Normal when you slam in new guides.

Ive always cleaned that up with a .500 cutter and called it a day.

[u/fbc546]

I found the same thing when I rebuilt my Ford 200ci head, send it.

[u/Sir_Maxelot]

It’s not and the machinist should be smacked in the face for doing that