swapping motors - in a different sense

On a bit of a whim, I posted a CL ad last night, looking to trade my half-rebuilt big block Ford for a 350 SBC, since I don't have anything to put the 460 into. Now it occurs to me that I don't really know how to assess an engine sitting on a stand, aside from visually confirming there are no gaping holes in the block out of which important insidey parts are hanging. Add to that the fact that I don't know SBC motors at all (yet), and I realized I'm flying a bit blind here.

So, if you were going to look at a rebuilt SBC to make sure it wasn't about to cost a grand or so in rebuild parts, what would you be looking for?

I'd just ask about what sort of service it was in and how recent the parts on it are. Then I'd do a compression or leakdown test. If nothing else, ask if the crank can be spun 720 degrees.

The only way to verify what you're getting is to pull @ least one head (if you don't have access to a scope) and drop the pan to pull @ least one rod cap and main cap. If the owner balks, I'd walk away unless you don't mind planning a rebuild.

pull a head and look at the top of the piston for a overbore mark. At this point, look for a virgin (no 0.030 or 0.040 and WAY NO to a 0.060 on the piston).

This is in addition to Graefin10's suggestion. Check a bearing or two for weird wear.

Graefin10 wrote: The only way to verify what you're getting is to pull @ least one head (if you don't have access to a scope) and drop the pan to pull @ least one rod cap and main cap. If the owner balks, I'd walk away unless you don't mind planning a rebuild.

specifically, pull the #1 main cap since it's the farthest from the oil pump. you can remove the bearing shell from the main cap and see if it's got a number stamped on the back telling you how much (if any) the crank has been cut. No reason to be afraid of a crank that's been cut 0.030" undersize if the journal surface looks good and the bearing doesn't show any unusual wear. oh, and if the price is right.

i guess using distance from oil pump as a guide, pull the #1 rod cap too.

Good advice, thanks guys.

potential trader said: 355 chevy motor built 30 over comp cam aluminum intake has the angle plug heads screw in studs and guide plates

Given that it has more aftermarket stuff than my 460, I may not be scared off by the 0.030 overbore. I'll ask him if he doesn't mind one of us digging into it.

Hard to tell from his email, but I think he's implying it hasn't been run since the rebuild. Went in a '35 truck that he never finished, sold the truck as a roller, or something...

On the flip side, what would you want to know as a potential buyer/trader of my engine, given that it hasn't been run since the rebuild got stalled halfway through? (Cliff's notes: got the block hot tanked and checked, crank checked and cut, stock pistons, new rings and bearings, mild cam; heads off and disassembled, oil pan still off, all stock manifolds etc.) Mine is stock bore still and the crank was only cut 0.010 - and I should (note the emphasis) have paperwork to back that up. I suppose I could also show him that the torque required to move the crank manually is well within spec.

Anything else?

Have 'em FIRE IT UP for ya!

run a compression test on it. it's easy enough to pull all the spark plugs and hook up a starter.

If the engine has been sitting a while or has never been run a compression and leak down test may not read accurate. Rust can form between the valves and seats.

I shipped an engine cross country. First thing they did after uncrating was a compression and leak down. Guy called and bout climbed up my butt about bad compression. I told them to run it, they did, it passed w/ flying colors. The engine only sat a few months w/o running but obviously enough to form rust between the valve and seat.