themack56

iTrader: (70)

i need to know what needs to be done, so i can fit a 4.250 stroke in a 4 bore ls1 block. im buying this block and it needs a quick hone, for me to achieve a 427 i need a 4.250 stroke. they offer these but i dont know if theres any clearance issues, does my shop has to blue print the block to achieve this, all i want to know is can i do this and what needs to be done?

67Firebird455

iTrader: (27)

Wish I could answer that for you bud... That'll be a freakin torque monster with that 4.25 stroke though, I can promise you that! I'm curious to hear what others have to say.

themack56

iTrader: (70)

i mean if they offer the crank, it can be done safely then right? dont know cause this car is going to be street driven but to the track couple of times a year, it will not be daily driven, more like a friday saturday and sunday car lol, need to get the ls1 masters in here for their opinion

xfactor_pitbulls

iTrader: (16)

Good luck clearing typical ls1 pistons to the crank/reluctor wheel. You are going to need custom longer sleeves or maybe a small deck spacer. But hell, if you have to go to that trouble, go ahead and do a 4.190" bore x 4.400" stroke. Hello 485 CI. Doubtful you are going to pull it off in a "normal" setup.

Brandon

themack56

iTrader: (70)

so what do you think. should i just go with a 4 stroke and just do a true ls1 402?

xfactor_pitbulls

iTrader: (16)

If you are using an LS2 block that is the safe bet. Any other way you will be looking at adding $1K plus for the extra stroke.

themack56

iTrader: (70)

i already have the ls1 block and it was resleeved by the previous owner, it needs a quick hone, and vuala perfect, dont see whats wrong with using an ls1 over an ls2 block

DavidNJ

Actually, you need something like a 4.175 stroke. This is a common Ford size for their 9.5" and 9.2" deck height blocks. Lunati makes a 4.185" crank. Although they offer the crank, they don't offer a rotating assembly with it. And the crank may not be a stock item. You will probably need custom pistons for the right compression height.

Beast96Z

iTrader: (21)

The 4.250" stroke can be done in the LS1 block with stock sleeves. The ring placement is something left to be desired, but it can be done. I believe G-force racing on here has a Impala with this set-up. Personally I wouldn't do it, but it's your baby and your wallet. I'd go with a Eagle 4.100 stroke personally. Save yourself $1500 on the crank and another $500 or so on custom pistons. You'll also save tons of time.

DavidNJ

How long is the LS1 sleeve? Wouldn't that need something over 5.5", closer to 6"

LOnSLO

iTrader: (15)

Just built one of these about 6 months ago. Had to use a small journal crank, custom Oliver billets, and a super thin piston. Very expensive stuff, not to mention the custom work on the block. Spare yourself.

Uthinkso

4.125" is as much as I would go. I've used that stroke in an iron application and the piston was certainly custom.

Ring pack and pin location weren't the greatest but it makes good power.