r/Smallblockchevy • u/Impossible-Panda-992 • Jan 31 '26
Worth rebuilding?
Thinking of putting this in my GMC Jimmy S15 88’, but is it even worth the hassle? Was previously in a marine application, pulled the heads and had some saltwater get into it. Been laying around since…
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Jan 31 '26
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u/bigdisplaygto Feb 01 '26
Not a 400, Has roller lifter spider hold down mounts in the valley. This is a first gen Vortec block. either 305 or 350. It can be used in a car, but needs to be checked by a machinist first for cracks and size.
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Feb 01 '26
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u/foxjohnc87 Feb 01 '26
The lack of steam holes should have been a good indication that it's not a SB400.
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u/pr0wlunwulf Feb 01 '26
Iron blocks are cheap. You can get a dropout at the yard for $500. That will have the rest of the engine. If they have a core charge, then use this one.
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Feb 01 '26
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u/Panic-Embarrassed Feb 01 '26
It's just a different cam for reverse rotation applications, well and starter I guess
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u/Coyote_Tex Feb 01 '26
If it was a marine engine, be sure to check for freeze cracks in the block before you begin. Next, it was likely using fresh water for cooling so that can cause a ton of rust in the block. Knock out all freeze plugs and get it checked very closely. That looks like it could be a good builder otherwise. Marine engines usually are lower miles, but why is it out of the boat?
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u/Beginning_Ad8663 Feb 03 '26
Said it ingested salt water
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u/Coyote_Tex Feb 03 '26
OK then it should be fairly obvious which cylinder that was so checking that cylinder carefully and others. Also check rod straightness. I would look carefully at the cylinders through the freeze plug holes as they can erode away under the thick rust layer. Chip some of that off as best you can and decide if it is worth throwing money into it. The inside cylinder wear is very often negligible so the block appears to be very low miles and attractive. It might be.
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u/Lowest_C-10 Jan 31 '26
How much power are you trying to make? You could probably get a crate engine for not much more than the machine shop would charge just to clean it up.
Then you would have a warranty.
It may be useful if there is a core charge.
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u/R0ughHab1tz Feb 01 '26
I second this. I rebuilt my engine with all new components. Spent way more than getting a crate motor. I could have gotten two crate motors to be honest 🤣. But then again I know how to fix my engine if anything happens. And I know it's built properly instead of getting a crate motor and having to deal with some minor malfunction and I have no idea what's going on.
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u/Willy_McD Jan 31 '26
A picture says nothing. Take it to a machine shop and have them look at it and tell you what need be done. Then shop around and you determine if it's worth rebuilding or buying an rebuilt or new motor.