View Poll Results: Which would you choose and why 427ci or 440ci LS7?
427ci LS7
8
29.63%
440ci LS7
19
70.37%
Voters: 27. You may not vote on this poll
427ci vs 440ci LS7
As I said in the Gen IV thread the 440 gets my vote on the larger cubes. For FI my bets are the 427's 4.00 stroke would be better suited, although I don't see any problem with the 4.100 stroke of the 440 if you want to go that route. The thing is if you are pricing it through TSP they don't cost anymore for a LSX block and my bet would be that the cylinder bore in the LSX would be more stable under boost/heat and seal better due to the iron block versus the aluminum cylinder distortion.
Kind of like the LSX in your avatar... Of course I am partial because we are currently building a LSX 454...
Kind of like the LSX in your avatar... Of course I am partial because we are currently building a LSX 454...
Last edited by Azrael; Feb 29, 2008 at 06:56 AM.
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As I said in the Gen IV thread the 440 gets my vote on the larger cubes. For FI my bets are the 427's 4.00 stroke would be better suited, although I don't see any problem with the 4.125 stroke of the 440 if you want to go that route. The thing is if you are pricing it through TSP they don't cost anymore for a LSX block and my bet would be that the cylinder bore in the LSX would be more stable under boost/heat and seal better due to the iron block versus the aluminum cylinder distortion.
Kind of like the LSX in your avatar... Of course I am partial because we are currently building a LSX 454...
Kind of like the LSX in your avatar... Of course I am partial because we are currently building a LSX 454...
BTW, 440ci LS7 has 4.10" stroke crankshaft. Just a correction.
So, unless FI, 440ci would be better. Also, you mentioned good point about LSX iron block being same price as LS7 aluminum but I read in this forum LSX iron blocks have some issues
I meant the 4.100 stroke on the 440... The LSX problems never really saw the light of day on the production blocks and GMPP halted production to make sure the problem was totally resolved. The new blocks are due to start trickling out next week to fill back orders and so they should be available soon. If you have any doubts about the LSX block look for posts from Robin L and he should help put some of that asside.
WOW deja vu.. you have this quesiton in two sections
Last edited by 99blancoSS; Feb 29, 2008 at 10:55 AM.
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From: Copenhagen
I doubt you will see much improvements with a fast or oem intake... they seem to be the weak link in building big N/A numbers... with a singleplane and FI.. id go with 440, in an ls7 block to keep the valves as unshrouded as possible
We have built SEVERAL 440 LS7 strokers making OVER 600rwhp thru cathedral port heads and ported FAST 90mm intakes. We have one customer with over 32000 ABUSIVE miles on his engine with ZERO mechanical issues.
When I was looking into a bug cube motor I was told that the LS7 block is fine if you are N/A...but if you try to spray with it the cylinder liners crack easily and an Darton sleeved LS2 block is a better choice.Im not sure if this is true...jut what I have been told.
IMO, if you are going to run a large N02 shot or FI with a motor that big I would see how the LSX blocks turn out and go with that in either 427 or 440 ci.
IMO, if you are going to run a large N02 shot or FI with a motor that big I would see how the LSX blocks turn out and go with that in either 427 or 440 ci.
^ Wrong. Internet mumbo jumbo. They're plenty of cars out there that have made tons of power with stock LS7 blocks. I do agree on the second part though. The extra 2 bolts per head really helps with common pushing water issues.
An equal size turbo for example will make more peak hp on a smaller cubic inch motor. ONLY when the turbo/supercharger is moving all the air that it can.
