Turning LS3 into 427ci

[62nalide]

Iorn block FTW!
Throw everything at it and it just laughs

[Taco Time]

Originally Posted by M3hta1

Hi Gents,

Hopefully this is the right section. I have started doing research and searching forums. From what I have found so far reaching is the following.

The LS3 376cui with a 4 inch crank shaft will become 417cui. Now what are my options to hit that 427 cui mark? Just a set of oversized heads?

I have a mild/semi aggressive cam, headers, cai right now and really like staying NA with a 100 shot or so.

Does anyone have additional info on making an LS3 417ci? I'd like to read more about this. What parts are needed, fuel mileage, expected cost info, hp gains, etc.

[axis]

Originally Posted by Taco Time

Does anyone have additional info on making an LS3 417ci? I'd like to read more about this. What parts are needed, fuel mileage, expected cost info, hp gains, etc.

Hit the "search this forum" button in the upper right hands side of the screen and type in stroker build. Should give you quite a bit of reading.

[Taco Time]

Originally Posted by axis

Hit the "search this forum" button in the upper right hands side of the screen and type in stroker build. Should give you quite a bit of reading.

thanks. I've done a little searching, but I didn't really know what terms to search for.

[1989GTA]

Originally Posted by Taco Time

Does anyone have additional info on making an LS3 417ci? I'd like to read more about this. What parts are needed, fuel mileage, expected cost info, hp gains, etc.

I would say crankshaft, piston and rings for sure. I think you can reuse your rods if you wanted or go forged for the extra safety. Milage, probably down a couple on the highway. Can't help on the power gain.

[thahemp]

Right. You can buy full kits from TSP if that simplifies it for you. I would do the rods while you're in there. Your gain from stroking to 416ish is going to be torque. Add cubes for TQ. It adds some HP, but you probably wouldn't be impressed. You could bump your CR up with heads at the same time and maybe end up around 550/550. That's a great place to start adding nitrous with your new, forged rotating assembly.

The parts aren't all that expensive, somewhere between 2 and 3k for the rotating assembly. You will have to pay a machine shop to put the shortblock together for you though. You'll also want a new cam. You might also be looking at dealing with a fuel system. I know my stock pump is dropping PSI with just bolt-ons and a cam.

[Taco Time]

Originally Posted by 1989GTA

I would say crankshaft, piston and rings for sure. I think you can reuse your rods if you wanted or go forged for the extra safety. Milage, probably down a couple on the highway. Can't help on the power gain.

Originally Posted by thahemp

Right. You can buy full kits from TSP if that simplifies it for you. I would do the rods while you're in there. Your gain from stroking to 416ish is going to be torque. Add cubes for TQ. It adds some HP, but you probably wouldn't be impressed. You could bump your CR up with heads at the same time and maybe end up around 550/550. That's a great place to start adding nitrous with your new, forged rotating assembly.

The parts aren't all that expensive, somewhere between 2 and 3k for the rotating assembly. You will have to pay a machine shop to put the shortblock together for you though. You'll also want a new cam. You might also be looking at dealing with a fuel system. I know my stock pump is dropping PSI with just bolt-ons and a cam.

Thanks for the help guys. What's the full name for TSP? I was wanting to do a cam already, and figured it might save some money if I did this at the same time.

[thahemp]

Texas Speed and Performance

https://www.texas-speed.com/c-503-ro...ssemblies.aspx

You will need a bigger cam with those extra cubes. I would recommend Brian Tooley Racing to spec you a cam. He can probably get you the rotating assembly too. Give him a call and he can set you straight.

[Pro Stock John]

Stroker kit, to stroke your stock engine to 417 CID, would typically include crankshaft, rods, pistons, rings and bearings. Then the rotating assembly might need to be balanced, and then everything assembled.

[VADER SS L99]

You can safely turn your LS3 into a 427-454 with a sleeved block from ERL. Without sleeving I would stick to the 4" crank stroke for 416-418ci.

[thahemp]

And if you're going with ERL... why not just go superdeck 502.

[thahemp]

Weird. Didn't they used to offer a Superdeck II? I could swear I was drooling over their 500+ blocks at one point.