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need help with a chevy 402 build

Moderator: speedfreak

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huntin76

Posts: 5

Joined: Sun Jan 16, 2011 8:35 am

Post Sun Jan 16, 2011 7:15 pm

need help with a chevy 402 build

Hello all I am in need of help. I just bought a 402 that has 427 heads on it. It also has a snowflake (?) intake on it. I want to get around 450 hp out of it. It will be going in a 1969 chevelle with a T350. I want to know what combo I need to reach it and if the 427 heads should stay or go.


Sorry it took me so long to get back on here. I am in the Army and time is always against me lol. Here we go

block, 3999290, 2 bolt main ,1972, passanger

heads, oval port, 336781, open chamber.

as far at the crank I dont know yet. I havent taken it appart. I have a 69 chevelle and i am gonna clone it to a SS. Right now I have a 4 bolt 350 bored 30 over, world street torquer heads 202, 194. blue print crane 327 cam. 6AL msd ign. On the build like any I know ya get what ya pay for with that said I dont want to go the cheapest route but I am not John Force only John Hall LOL. Thanks for taking the time help me with this
Last edited by huntin76 on Tue Jan 25, 2011 7:20 am, edited 1 time in total.
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speedfreak

User avatar

Posts: 170

Joined: Sat Feb 18, 2006 5:15 pm

Location: Holts Summit Mo.

Post Sat Jan 22, 2011 9:00 am

Re: chevy 402

First off welcome and thanks for posting. 450hp is possible we really need to be sure which heads you have by doing some internet research and looking up the casting numbers. As with every engine it really comes down to the heads and camshaft and how much your willing to spend. Here are a couple links to 396/402 build up's. Hope this helps

http://superchevy.automotive.com/92031/ ... index.html

http://www.classictrucks.com/tech/0702c ... index.html
Pimpin' ain't easy !!!
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huntin76

Posts: 5

Joined: Sun Jan 16, 2011 8:35 am

Post Wed Jan 26, 2011 8:39 pm

Re: need help with a chevy 402 build

correction it has 454 heads on it. Also can someone please tell me the deal about a "snowflake" intake. Should I heep the heads or get diffrent ones? I have built alot of SB but never a BB. PLEASE people help me out :!:
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speedfreak

User avatar

Posts: 170

Joined: Sat Feb 18, 2006 5:15 pm

Location: Holts Summit Mo.

Post Thu Jan 27, 2011 10:56 pm

Re: need help with a chevy 402 build

I'll do some research on your intake.
Pimpin' ain't easy !!!
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huntin76

Posts: 5

Joined: Sun Jan 16, 2011 8:35 am

Post Mon Jan 31, 2011 9:27 pm

Re: need help with a chevy 402 build

336781 is the # on the heads. Like I posted last they come up for a 454 not a 427. sorry about that and thanks for the help on the web sites.
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speedfreak

User avatar

Posts: 170

Joined: Sat Feb 18, 2006 5:15 pm

Location: Holts Summit Mo.

Post Thu Feb 03, 2011 9:06 pm

Re: need help with a chevy 402 build

the 781's come with 118cc chamber, 256/114cc ports. They are a very respectable open chambered factory head and will support plenty of horse power. After a little research about the intake it seems they go for about $300 dollars and even more depending on the date code. In my opinion your best bang for your buck is to find a 454 block. Craigslist is pretty easy to find one. You could then use your 396 crank to make a 427. These days and a 496 kit with a cast crack is very good buy also. Unless your very attached to the intake I'd sell it and make a few bucks and buy a newer intake that will make more HP. And with the rest of the $, help with your build.
Pimpin' ain't easy !!!
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huntin76

Posts: 5

Joined: Sun Jan 16, 2011 8:35 am

Post Wed Feb 23, 2011 8:57 pm

Re: need help with a chevy 402 build

Thanks so much for the help. I will take all the advice you have given me and run with it. You sure know alot more than I do on this. Thanks again John

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