Generation IV Internal Engine - Looking for 4.125 Bore




View Full Version : Looking for 4.125 Bore


Bill71
03-08-2012, 09:48 PM
What is the most cost effective way to get a block with big bore sleeves? I've been wanting to build a forged LS3 bottom end but am wondering if it would be worth it ($$) to start with a big bore. What are my options?


LS1MCSS
03-08-2012, 11:03 PM
You can use a GM LSX block, a sleeved aluminum block, or an after market block. The cheapest will either be the LSX block or sleeved LS1 block.

COPO9560
03-09-2012, 06:53 PM
If you already have a LS3 block, dry sleeves are your cheapest option. If you have a LS1 block, only option is wet sleeves - more money but stronger build.

Take a look at ERL's website - many options to work from.

Least expensive option really depends on what you have on hand. If you have a complete LS1 engine, covers etc it will be less overall to wet sleeve this versus buying new LS2/3 block, covers etc and dry sleeving. Short block is one thing - 4.125 bore opens up a lot of great but expensive head options. Overall a fantastic engine can be built but it will be costly to complete. Need to ask yourself if the gains over 408 are worth the cash you will have to pay.


Unreal
03-09-2012, 09:13 PM
Or pick up a LS7. I sold my LS7 shortblock for $3500.

Bill71
03-10-2012, 03:49 PM
If you already have a LS3 block, dry sleeves are your cheapest option. If you have a LS1 block, only option is wet sleeves - more money but stronger build.

Take a look at ERL's website - many options to work from.

Least expensive option really depends on what you have on hand. If you have a complete LS1 engine, covers etc it will be less overall to wet sleeve this versus buying new LS2/3 block, covers etc and dry sleeving. Short block is one thing - 4.125 bore opens up a lot of great but expensive head options. Overall a fantastic engine can be built but it will be costly to complete. Need to ask yourself if the gains over 408 are worth the cash you will have to pay.


I do not have a block yet. I was planning to go LS3 but I really wanted to maximize cubic inches with out running a long stroke. The LS7 block is way too much $ for me.

I've seen some aluminum 5.3 blocks for sale on Ebay cheap. Not sure if they would be a good candidate. What is the max bore size on the 6.2 block using wxisting sleeves?

COPO9560
03-10-2012, 06:37 PM
You can go to 4.185 on dry sleeved LS3 block. You might contact a couple guys about installing sleeves, 5.3's are candidates here as well.