Can i fit flat top ACL pistons with out any other mods ! My reconditioner says dont do it,aussie forum says it will increase comp to 9.5 to 1,anyone had experience doing this ! It needs to be rebored due to wear and i can get .20 thou over pistons. Thanks.
rod-zone,
Apr 27, 11:26pm
Go for it.just double check Valve to piston clearance (more so if you have a big cam fitted)I fitted similar flat tops to my 327 with no problems at all.just be aware you will probably need to run 98 fuel or a 91/Av gas mix if you are going to drive it hard with all the timing you can get into it. Gav
modie61,
Apr 28, 12:02am
Thanks Gav,will have to get it bored by another reconditioner then. Im not getting any other mods done to it. Funny thing was i couldnt get dished standard type pistons in oversize for it from ACL, said they no longer make them,strange i thought.
mram,
Apr 28, 1:44am
Make sure they are 304 flat tops and not 308, is it an efi 304 or a LV2 black 304 carb! I would have thought you might have to remap for more fuel with more compression
modie61,
Apr 28, 5:31pm
It is a vu 304 efi and the pistons are for a 4.9 efi Commodore vn 1990.
mram,
Apr 28, 6:17pm
Yep I would go for it, but plan on a chip upgrade and/or some dyno tuning, as not to lean it out, the increase in power will be worth it
modie61,
Apr 28, 9:32pm
Crikey it seems like a lot of extra work when all i wanted to do is recond my motor. Its not as if its an uncommon motor either,whats going on ,cant you rebore or recond you own motor any more !
punkboy,
Apr 29, 12:13am
getting the flat tops cheap or somethin! your engine guy should be able to source dished pistons no probs,then no need about remapping and all that other sh#t.
modie61,
Apr 29, 12:32am
Flat tops not cheap,reconditioner priced correct dished pistons at $720,when he went to order them there was no stock. Ive found some cheap and nasty looking ones in Aus,but they wont guarentee them and if they are wrong there is no refund. I also got a quote to recond the complete motor which was $6000.
Ive asked all parts suppliers that i know and they will get back to me tommorow.
rod-zone,
Apr 29, 4:56am
Don't worry about the re-Map.or extra fuel the pistons won'tmake that much difference, like ive said maybe just use 96 or 98 from now on
modie61,
Apr 30, 12:41am
Well ive talked to 3 reconditioners and they all say dont do it,they have had probs before,so i will keep on truckin to find some dished pistons,got 1 good response so will follow that up tommorow,thanks.
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