HELP! 2 diff head castings on a ls motor?

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Jan 11, 2016 | 06:37 AM

thyreaper

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HELP! 2 diff head castings on a ls motor?

I picked up this 01 trans am and it was suppose to have a "7.0" ls motor in it but i noticed it running like it has a intake leak and a lifter taps some, upon further digging in i noticed it has 2 different heads on it which are casting #'s 5364 and 823 ... The block appears to be alum ... are the intake ports different? that would explain why it may be leaking.. it pulls hard and the lifter only starts tapping after its warm and it comes and goes but under low speeds and low rpm it acts like its missing but under 1/3-1/2 throttle the miss goes away and it pulls hard with not miss or stumble.. let me know yalls thoughts id like to know how much different the heads are and if that is causing me issue which will help me decide on what to do... i may just find 1 matching head to either casting number ect..... but i gotta figure it out first lol

Jan 11, 2016 | 08:23 AM

KCS

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Ports are the same, they're just two different casting numbers of the same head (LS3).

Jan 11, 2016 | 01:22 PM

thyreaper

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is there a way i can tell if it is a ls7 block or if i was lied to?

Jan 11, 2016 | 02:17 PM

blk00ss

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7.0 is stamped on the back of the block and the front. But it's obvious you was lied too lol

Jan 11, 2016 | 02:32 PM

MuhThugga

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From: Wilmington, De

It could be a LS3-based 427 stroker.

Jan 11, 2016 | 03:01 PM

dogsballs

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From: melbourne (Aus)

5364 and 823 are both rectangle port. There are some very very minor casting differences, but doubt it will make a difference. A 6.0 or 6.2 will be casted on the front if it was built up

Jan 11, 2016 | 05:09 PM

handyandy496

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lite valves on one side. unless new valves. If ported. Then they would be the same. If it is a ls7 the engine is worth alot more than the car.

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Jan 11, 2016 | 05:56 PM

thyreaper

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but can i see the stamping with the motor still in the car and the trans hooked up (6 speed) ? i saw pics of the stamping when i bought the car that said 7.0 on the block but I havnt seen the stamping myself... I didnt pay a fortune for the car so even if its a basic ls3 then i made out good... but im looking at buying an intake because the stock one is leaking and I dunno if its the good intake or not and the stock one thats on it is cracked so im replacing it , what intake is good for it? i seen where the FAST ones where not worth the $ spent...