[HWYSTR455]

Yeah, I dunno, I've run a bunch of 400ci engines in the 350-400hp range and had problems with mech pumps. What really makes it slap you in the face is when you start going to steeper gears. THEN you realize 'Houston, we have a problem'.

And these problems were across multiple cars, and just about every mech pump out there. I had the best luck with the Carter ones, just to say.

Performance isn't a static value, it changes even through just seasons and temps. What may work in the winter won't work in the summer, and visa-versa.

I recall getting a mech pump setup (step-up actually) and only had what I thought was a hint of a problem, and that appeared to be solved by the new pump. I had intermittent bogs at different points, and under certain conditions. So I thought to myself 'it must be the line size'.

So I went to 1/2" line. The issue was no longer intermittent, and happened all the time now. So started replacing mech pumps and nothing solved it. The mech pump just couldn't handle the volume.

So did I go back to 3/8" line? And mask the problem? Of course not. I ran external e-pumps for a while, and there were some that lasted longer than others. So added a return (bypass regulator), and that made the pumps last longer, and less chance of vapor lock.

You can go thru posts here as I traversed some of that experience, but most was in the 80s & 90s. In the 80s, with a somewhat mild 455 & 3.55 gears, I had to run an e-pump, everyone did. That's one of the things that brought Holley a bunch of revenue, the blue & red pumps. Why did so many use them back then? Because they knew delivery was a common problem with the factory setups.

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