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4.3 bore .30 over hp?

Old 08-21-2013, 11:48 PM
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Default 4.3 bore .30 over hp?

hey guys im new to the forum just picked up a 1998 zr2. the guy before me owned a hot rod shop. he had a bit of knock so he pulled the motor had it cleaned, bored .30 over, honed, deck plates, arp head studs, valve job, and a towing cam put in. just wondering what cubic in im at now as well as an estimate on hp and tq. thanks!
Old 08-21-2013, 11:56 PM
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roughly, you would be at like a 265 CI. and as far as horsepower, 200 MAYBE!! remember, they only had 190 HP when they were brand spanking new! .030 over isnt much and is done to basically "re-round" cylinders and remove any imperfections in the bore.
Old 08-22-2013, 12:04 AM
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yea i figured that just wanted to get an idea not looking for a lot of power just was interested in what ppl thought it makes
Old 09-14-2013, 07:46 PM
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most overbore pistons are made to compensate for the extra area gained as to not mess up the compression ratio. You usually have to go out of your way to get different otherwise. The cam would make the most difference but towing cams are usually more torque based and move the power curve down into the normal driving range. Your around stock numbers, but remember most vehicles arn't near the stock numbers with alot of mileage
Old 09-14-2013, 09:07 PM
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The .30 over won't get you anything. Maybe a dyno could tell, but the seat of your pants definitely can't!

The towing cam might make it feel a little quicker off the line, though, owing to having more torque on the bottom end.
Old 09-14-2013, 09:16 PM
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You guys realize it was bored out .030" larger and not .30", right?

That's a huge difference.
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