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#1 |
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Join Date: Sep 2006
Location: Kilgore TX
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A fellow has contacted me in question about rebuilding a 1971 Olds Cutlass 350 original engine. He wants to increase the performance within reason. I know the customer and his car and his style so a factory iron head will be the best choice. It there a factory head better that the 1971 350 model? And is such a head easily available. I would like to make him a 400 horse package.
Who is in the know with Olds 350 heads? And for that matter, 350 Olds engines in general. |
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#2 |
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Join Date: Dec 2001
Location: Elysburg, Pa
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A good start would be putting in the 2.005" intake to replace the 1.88" and some pocket porting.
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#3 |
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I’d suggest 1968-1969 #5 or 1970 #6 heads. You’re gonna need more than just a head swap to make 400 hp, though. I’d recommend a bit more compression, a respectable cam and valvetrain upgrade, a Performer RPM intake, a decent pair of headers, and a reworked Q-Jet. 400hp is achievable and if maintained and not over revved, should be stout and live quite a long time. You should be fine with a factory crank and rods (reconditioned) at that level.
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#4 | |
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The best intake is either the Performer RPM or Holley Street Dominator if you can find one. I would also recommend the use of a hydraulic roller with Johnson Lifters, for Pontiac/Oldsmobile applications. The Chevy lifters have the oil band in the wrong location. |
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#5 | |
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#6 |
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I just watched a video of some dyno testing on a 70 W-31 350 Olds engine
10+ to 1 compression with 2.07 intake valves and the factory aluminum intake with headers It made exactly what the factory rating was 325 hp at 5400 Was a stock cam and freshly rebuilt +.030 engine Could one make 400hp ? Sure but it obviously would take more than just some different factory iron heads !!
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Rich Biebel S/C 1479 Stock 147R |
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#7 |
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First question you need to know, is this car going to be operating on non-leaded pump fuel? If so, you'll need to use a cylinder head with hardened valve seats. If you want 400+ horsepower out of a 350, I would recommend a set of Edelbrock heads along with an Edelbrock or Holley Dominator intake that can be ported to match the heads. By the time you prep a set of OEM heads, you would be further ahead with the Edelbrocks. Add a set of forged pistons, camshaft that would make power to 6500-7000 and upgraded valve train with beehive springs. Don't forget a good set of 1-3/4" or so headers and free-flowing exhaust. I would use a race-prepped Q-Jet but that's just me. If it's a street car, a minimum of 3.91 rear gear out back will be required.
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Jim Kaekel 3836 STK |
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#8 |
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Olds made a 17 degree alum head for their Diesel block back in the 80's. That head would make a lot of power but they are hard to find. Someone on here that knows Olds better than I could tell you if the stock block & the Diesel have the same bolt pattern.
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#9 | |
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The diesel block, although stronger, has a larger main size as the big block Olds. Some racers use spacers in the mains with the small block bearings. There was also a limited run of Olds small block racing blocks that are hard to find. For a low cost small block forged crankshaft, you can use the Olds 330 crankshaft, however, you have to use the corresponding Olds 330 or 425 flexplate. |
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