LS1 based 402 ?'s

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Nov 17, 2006 | 06:44 PM

oct03gto

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LS1 based 402 ?'s

I need to know everything I cam on building a 402 from my 04' GTO LS6 based block. They used LS6 blocks for the LS1 in 03', and 04'.

I need to know what I am going to run into. I am buying a Lunati rotating assembly. Having it balanced with an under driven pully, and new light weight flywheel. Will this block take to boring to make the 402? What kind of grinding will need to be done for crank clearances?

What heads are suggested? I was thinking of the AFR 225's with mild porting. I am looking for 11.0:1 compression. Using a FAST intake, and 90mm throttle body.

What else do I need? What kind of power should I expect?

Not sure of the cam yet. I am thinking a 224/226 with 114* lobe @ .600 lift.

Any help would be great. Thanks all.

Nov 17, 2006 | 08:04 PM

speedyss

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From: edgewater, fl

depending one the stroke you might have to resleeve the block, what kind of stroke are using.

Nov 17, 2006 | 09:02 PM

oct03gto

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I am unsure. I thought there was only one way to make a 402 out of an LS1/6 block.

I also thought that the 402 is made by using a 4.00 bore x a 4.00 stroke. That stock block canot handle the little boring needed for this???

I see you have a 402. Did you build it? Or buy something like a crate engine?

Last edited by oct03gto; Nov 17, 2006 at 09:11 PM.

Nov 17, 2006 | 09:32 PM

SLED28

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You will need a LS2 block at 4.0 bore and a 4" crank. I have one in stock with AFR 225 heads if your interested in buying now. You can either email me at dave@cdnperf.com or call me at 416 795 6981 for more details. This motor will make between 510-530rwhp.

Nov 17, 2006 | 09:48 PM

Beast96Z

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Your LS1/6 block can NOT take that kind of a over bore. Max is actually about .010", leaving you .090" away from your desired cubic inch. Best you can do with your block is a 396 which is a 3.910 x 4.125". Lunati sells that kit. If you want the 402, you need the LS2 block which comes with a 4" bore.

Nov 18, 2006 | 12:33 AM

Steve - Race Eng

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large bore LS6

The LS1 LS6 blocks can go only to 3.905" max. bore without sleeving.

You have a few options. You can purchase a new LS2 block 4" bore or L92 4.060" bore block. Or if you want a 427" or larger, I can install Darton MID sleeves in your current block. Bore size on the LS6 MID ranges between 4.125" and 4.160" max. bore. The large bore will allow you to run the LS7 heads, manifold for a really stout engine.

Steve

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Nov 18, 2006 | 03:10 PM

oct03gto

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Well, I need to recalculate what I am doing. I am awaiting my 2004 GTO LS1 engine. I will need to sell that, and then buy an LS2. I want to build thins engine myself. I have a friend who builds circle track cars, and engines here in RI. He will do all of the macine work for me. I was going to choose parts, and assemble the engine.

SLED, you and I have spoken befor about a 389 CI LSx based engine before.

PM me later please.