Heard a master tech say compression is overrated on small blocks

Was at a shop in Phoenix last week and this older guy said he's seen plenty of 350s run fine at 120 psi, but I always thought 150 was the minimum. Has anyone else run an engine with that low compression and had it still be reliable?

2 comments

2 Comments

troy_adams27d ago

Wait, 120 psi on a 350 just fine? That sounds low for a daily driver but maybe he's talking about a worn motor that still runs? I've seen small blocks at 130 psi that smoked a little but pulled fine for years on a farm truck. 150 is what I aim for on anything I build but it really depends on what you're doing with the thing. Low compression can actually help keep an old engine reliable if you're not racing it, just less stress on everything.

brookekelly27d ago

That "less stress on everything" part is interesting. Do you think running a low compression 350 actually makes the bottom end last longer, or is it more about just accepting lower power to get more miles out of a worn motor?