430 engine question

What can a 430 cu in block be bored to safely without any worries about wall thinning? The motor is from my 67 RIVIERA GS car that I pulled out of a field about a year ago and am starting to do some work on it to get it moving. The car supposedly sat in the field for about 20 years so it needs everything. I just pulled the motor and trans this past weekend. I took the heads off of the motor to see the bores and they all look pretty good.

I also was recently given a 455 out of a 73 RIV from my brother, but when I pulled those heads one of the pistons was cracked (#3), but all of the bores look good. Surprisingly there is no scaring in that cylinder even though the piece of the piston top and a portion of the top compression ring are no where to be found, even the valves look good. This motor was never opened since it was pulled from the car was being scrapped due to body corrosion, it was still running about 15 years ago at the time, obviously that cylinder had a problem though.

just asking, because I am not sure which block to send to the machine shop to start with. I know to keep the car original it would need the original motor and trans, but at this point I am not sure that that really matters due to the condition of the rest of the car. Although I have high hopes of making it nice, it is my retirement project.

Any thoughts/info would be appreciated.

Most engines, including the 430 are good to .060". Standard machine shop practice is to go from standard to .030". This is because virtually any cylinder will clean up with .030" and that makes .030" is the most common and therefore the most economical and available oversize for any motor. Almost any other size will cost more.

Depending on what you want out of the car, either motor will do a fine job of moving it along.

Several things besides originality favor reusing the '67 430:

The stock compression ratio on the 430 is 10.25 vs. the 455 at 8.5. Hp will be higher on the 430.

The 430 already has the switch-pitch controls for transmission mounted in place. No adaptation necessary.

The 430 does not have all the pollution equipment that the 455 has.

the 455 would bolt up to the switch pitch trans.

the 430 heads can be adapted onto the 455 block, which will give a compression bump. watch out for the oval water passage on the 455 block though. www.TAPerformance.com can clue you in

if you stay with the stock manifolds, the 1967 exh manifolds are supposed to flow better. the 67 intake will have less emissions crap.

i think the 73 might have the larger 800cfm quadrajet.

the HEI distributor didn't get introduced until 1974, so you'd still need to upgrade that.

if updating the 73 pistons you might as well bring them all up to ( at least ) 1970 spec.