Anyone Bored a 4.3 w/GM Aluminum Heads?

[tethoma]

I own a 94 S-10 PU w/CPI V-6. I took out the Hypertech Thermomaster chip and 160 Thermostat. Over time the setup ran too rich and caused the injectors to clog with carbon. I replaced two injectors over a 6 year period.

I also found out later that high Octane gas (93+) will cause the engine to shut off because it burns slower. The CPI is designed for 87 octane because is burns off faster. When you add the 160 Thermo and slow burning fuel the engine will shut off.

I’m now looking at naturally aspirated horsepower. I would like to bore the cylinder heads and add the GM Performance aluminum heads (90 degree). Has anyone had success doing this? Do I need to modify the intake plenum to allow more air? Headers would also follow this modification. Any assistance would help greatly.

As we know the L35 engine is basically a chopped 350. I'm sure someone out there has bored out a 350 and upgraded the heads. Please advise.

[jturkey69]

we took one .030 with .125 dome pistons, I had 40 some hours per head porting and polishing...the main thing is to leave the lil ramp in, but smooth it out. I know we buzzed it a few times to 6800 rpm, but it held its own in a G-body monte studded ice racer..first we ran a spreadbore carb, then switched to a Holley pro-jection. Its sitting in my uncles shop now bagged up for about 5 years now..lol

[923.4v6]

If I were you I would just buy a set of flat top pistons. You will get more power from that than boring dome may be to high to drive every day.If you buy a cam watch what you get the cpi has a bigger cam than the tbi engines and most you buy will be based off the tbi.