Mailbag: Finding Low-End Power in a 1970 Olds Cutlass Daily Driver

1970 Oldsmobile Cutlass

(Image/Hot Rod)

You’ve got questions, we’ve got answers. We work with the Summit Racing tech department to help you tackle your auto-related conundrums. In this week’s Mailbag, we’re helping a reader find low-end power in a rebuilt 1970 Olds Cutlass.

Q: A friend and I are rebuilding a 1970 Olds Cutlass. It has a 350 engine with 111,000 miles, and we want to add a little more low-end power. Here are our ideas:

  • Mill the heads and get a three-angle valve job.
  • Bore the block .020 inch over and rebuild with new cast pistons, moly rings, and new bearings and bolts.
  • Add an aluminum intake and four-barrel carburetor, high volume oil pump, new water pump, and double-roller timing chain.

We also need a recommendation on a camshaft and rocker arms. The Olds will be a basic, daily driver street car.

A: Here’s what we recommend for your Olds 350:

  • Don’t mill the heads more than is necessary to square up the block-mating surface.
  • Bore the block .0303 inch over and use a .030 over piston—they’re easier to get than .020 inch pistons.
  • Since you’re looking for low and midrange power, we’d stick with a standard oil pump.
  • For a camshaft, use a COMP Cams Magnum 270H hydraulic grind (224 degrees advertised duration, .501 inch lift). We also recommend a COMP Cams rocker arm kit that includes 1.6 ratio Magnum rockers, High Energy pushrods, and guideplates.
  • Add an Edelbrock Performer intake and Quadrajet replacement carburetor, a set of headers, and a 2 ¼-inch dual exhaust.

This combination should give your Cutlass plenty of low and midrange power.

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  1. Two other things you can do concerning oiling; remove any flashing in all visible/accessible oil passages, but DON’T hog it out, & gently remove the ‘hard’ corners in the oil filter adapter, but, as stated already, DON’T hog it out.

  2. Michael Jensen says:

    Apparently Summit Racing doesn’t offer an Olds 350 Forged Piston, or they’d recommend it. Of course, you did say, “low-end power” didn’t you? How about you clean and inspect the crankshaft, pistons, and block, and don’t even bore if you don’t have to? You’d save a buttload of money that you can spend on your camshaft and intake. If you just have to spend money, do it on the intake and exhaust and never lose sight of your goal to build “low-end power”!

    • Seasoned Tones says:

      Very True!! It’s a STREET CAR. I did that manuver a while ago.. With a SBC Zero deck block mill heads .30 over hyper slugs loopy stick… and found out Oh ..you gotta only use 93+ @ $4.00 gal.. and 11Mpg!!

  3. Steven L Jones says:

    Seasoned Tones means .030!

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