Low Compression Smog Big Block Turbo Question

[bigvegan]

Another question.

I'm looking for a budget-tourer, and every so often I'll notice an early seventies GM big block land yacht for sale. I think they're pretty cool, but as part of the emissions control in the early '70s, they took the compression ratios on a lot of these engines down to about 8:1, which doesn't make for a lot of horsepower.

That said, would this low compression make it that much easier to get a lot of power out of one of these engines without a ton of work if you could add fuel injection and a turbo? My thinking is that if the engine was sound, you could more or less leave the engine alone except for the intake and exhaust and fuel, bolt on / have fabricated a turbo kit and EFI, and have a pretty wicked motor for a lot less than building a turbo engine from scratch.

Am I completely off base here, or is this reasonably feasible?

Let me know.

[Goatman]

Well, first of all, those old low compression motors don't make any power because the heads suck. And any one you'd find that's old will need to be gone through, just to make sure its still 100% worthy. Chances are, its been sitting for a long, long time....


My 01' 8.1L has 8.5:1 compression and makes 345hp and 455 ftlbs right from the factory. They're cheap and easily attainable, so if it were me, my search would start there...


As far as the turbo's go, any motor can be adapted to one as long as the compression is right. I would say you'd probably want to get a cam as well.....

But those motors really don't need a turbo with the torque they make.

[pdq67]

Fwiw, my '75 454 P/U truck engine had true flat-top 1-notch cast pistons in it and '781 large oval open chambered heads!!!

I figure she was down around 7.9 to 1 CR..

I figure a freshen up and no more than an extra 150/200 hp from the blow and limiting it's rpm to like 5500 and it would live a long and happy life w/ good gas and a small blower cam..

pdq67