Our 5.3-litre LS is junk! – Carnage Plus episode 33

All is not well with the new 5.3L mill we picked up for the MX-5


BUYING second-hand parts is always a risky business, but it can also make for some killer bargain shopping if you get the right end of the stick.

Unfortunately, no such luck was to be had with the new 5.3-litre LS we bought for our MX5.7 Carnage project car. While the SBE twin-turbo LS1 that’s in the car now has cranked out 600rwhp and a 9.90 down the track, in truth the alloy-block mill is just about maxed out and holding the car back from its true potential.

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Our cheap-as-chips solution for that was to nab a 5.3 iron-block mill from the US. These iron blocks have been proven to handle a serious amount of boost in standard trim, and our plan of bolting on our trick heads from the old LS1, fitting a boost-friendly camshaft and opening the ring gaps seemed like a no-brainer – cheap horsepower is the best kind.

However, the red flags started coming thick and fast when Scotty began tearing this thing down. The knock sensors looked like they’d been freshly plucked from the Titanic wreckage, the lifters really weren’t interested in coming out, and pulling the heads put the final nail in the coffin. Several of the bores would’ve given you tetanus if you weren’t careful, and it became clear that the money required to fix it was not going to be conducive to a budget-friendly power boost.

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Thankfully, the seller is fully coming to the party and we’re able to indulge in a rare occurrence of returning used parts for a full refund. It still leaves us a bit stuck though, with the MX5.7 now in a holding pattern as we decide what to do with this little beast. What do you think we should do with it? Let us know.