ok my engine is gettin bored over 60 not by choice though, lol im trying to decide if i should get domed or flat topped pistons. and will the 60 over bore make me have to use a higher grade of gas and or will the flat topped piston do that also thanks in advance
Domed pistons generally raise compression and increase octane requirement.
Your question leads me to advise you find a mechanic who knows about tuning.
i definitely will.
.060 over will not make you need premium gas, but the high dome pistons will. If you want to stay with regular, use the flat top pistons.
ok thanks thats exactly what i needed to no thanks. i get my engine back tomarrow and i have the choice of either piston but will go with the flat top piston becouse gas is high enough lol. thanks again
If your OEM are dished, then you have to stay with them. I didn’t see your second post till after I posted.
Its all about compression ratio. All others being equal, domed pistons will give you the highest compression ratio, flat tops next and dished the lowest. The higher the compression ratio, the higher the grade of gas you need.
got u, and one more thing will it the 60 overbore couse me over heating problems
No it won’t cause overheating problems, but if the engine does overheat for any reason, the block will be more likely to crack. BTW, why 60 over and not 30.
This is why GM sells so many crate motors…No guesswork, no problems…
the machine shopped called today and said it needed to be 60 over i guess it was worn to bad for 40 over becouse that is what it was sapposed to be.
and should i go lighter on the thermostat tem i think its a 195 that was in there and if so what temp should i go with
theres a guy with a 40 over block already machined but has one sleeve has arp bolts and has been magnfluxed what do u think, should i get it
Stick with the 195 thermostat and keep what you have already spent money on. .060" is allowable, it just is now to the point where it can’t be overbored again. No worries, it’s still a tough motor.
You don’t seem to have much of an idea what you want or what the outcome might be.
i just wanted to make sure when i go to pick up my block and put everything back together that its not going to crack or mess up, becouse this will be my daily driver when im doin with it. i just found out today that it had to be bored over to 60 instead of 40 so just wanted to be sure. i already have everything needed to put it back together all new still at the shop with the engine. and i also wanted no what the diffrence between the piston were becouse the shop gave me a choice. they said 60 over would not make it have overheating problems, but i just wanted to make sure b4 i go ahead with it. and thank u all for the help yall made my decision easier, with short notice. i ran across that other bock on the internet and wanted to c if yall thought that was a better choice but i didnt no to much about the sleeve but im not going to mess with that. im going to go ahead and get it and get the flat top pistens. ill upgrade the radiater and keep using the electric fans thanks again
A little late to the party but you’d be much better off with a somewhat known block than one sleeved and bored. 040". The sleeve would be a red flag. Personally, I would have cut losses on the old block if it needed to go to the limit as 350 blocks are very competitively priced when compared to the total package cost of the work you’re having done.
The machine shop I used to deal with would have wanted the pistons in hand before they bored the block.
Different manufacturers and different piston materials can make a difference with the size of the bore.
Flat top pistons may require premium or higher octane rating of gas depending on the size of your combustion chamber in your cylinder heads. When you order pistons you’ll find that there is normally a chart in the catalog which shows the compression ratio based on the different chamber sizes in your heads.
I agree, stick with what you have, but you should have your block and heads magnafluxed after boring. The boring process can crack a weak block so even if it was checked before boring, it should be checked after, just in case. I concur with everything else above.
ok, i do have my block back from the shop, and there is a small chip at the end of the cylinder wall, will this be ok since its at the very bottom what do yall think and thanks for all the help,
here is a pix