1969 GTO 400 stroker question - Pontiac GTO Forum
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post #1 of 6 (permalink) Old 08-13-2016, 08:05 PM Thread Starter
 
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1969 GTO 400 stroker question

I have a numbers matching 1969 GTO 4-speed, 400 bored 0.030 over, RAIV cam & headers blah blah blah. It's time for a rebuild (last one was in 1980). I'm considering stroking it to a 461 and lowering compression a bit for today's gas (9.5/10.0 to 1 - currently 11+ to 1). Any disadvantage to doing this to my engine?

Thank you!
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post #2 of 6 (permalink) Old 08-13-2016, 08:37 PM
 
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Originally Posted by Andy Hughes View Post
I have a numbers matching 1969 GTO 4-speed, 400 bored 0.030 over, RAIV cam & headers blah blah blah. It's time for a rebuild (last one was in 1980). I'm considering stroking it to a 461 and lowering compression a bit for today's gas (9.5/10.0 to 1 - currently 11+ to 1). Any disadvantage to doing this to my engine?

Thank you!

Nope.
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post #3 of 6 (permalink) Old 08-13-2016, 09:51 PM
 
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If that is the original engine, I'd stash it and build your stroker, using a 481988 block and 6x-8 heads.

Lots of guys will pay big bucks for cars with the original engine. But, if you are absolutely sure you'll never sell, then I reckin it don't make that much difference.
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post #4 of 6 (permalink) Old 08-13-2016, 10:27 PM
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I stroked my numbers-matching original to 461, and I'm happy with the way it turned out.

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post #5 of 6 (permalink) Old 08-14-2016, 02:20 PM Thread Starter
 
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My GTO is the first car I ever bought, that was back in 1983. Probably not going to be selling it. Thank you for your response!
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post #6 of 6 (permalink) Old 08-15-2016, 12:37 PM
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There is no down-side to a properly machined and set up lower compression 461 based off a 400. More power, pump gas friendly, no need to rev to make a ton of torque. And with the right rear gear, likely no fuel mileage penalty, either, due to less throttle needed to get down the road. The danger of grenading your original engine with a stroker conversion is no greater than doing a standard rebuild on it, IMO, as long as the machine work meets specs.
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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, LeMans & GTO Engine Tuning and High Performance

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