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 Rebuild this 400?
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Steeno
Tribal Scout

USA
3 Posts

Posted - 27 May 2017 :  1:18:38 PM  Show Profile  Reply with Quote
Hi, I'm new to the forum.

Say, I picked up a '68 Firebird. It was an original 6cyl, 3 speed manual car. I bought it with a 400, Super T10 transmission, ceramic coated Hooker headers, flowmaster exhaust, no rust, good paint.

The 400 is shot. It's a '76 block (500887 code, B206 date code?) with 6x heads. All I can figure is it's really a 500557.

170HP engine off the showroom floor...

I'd like an honest 350HP. Is this engine worth rebuilding?

I appreciate your thoughts!

Bill Boyle
Horse Feathers (Charter Member)

USA
4797 Posts

Posted - 27 May 2017 :  3:20:30 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
The 557 block is not the most desirable; however, you should not have any problems building it into a 350HP engine. The 6x-8 heads need to be changed out with heads providing more compression. Those heads should be mildly ported, gasket matched with the intake and having valve springs that match the lift of the after market camshaft. I suggest running a hydraulic cam with a 112 LSA. Go with new forged pistons, have everything balanced, good dual exhaust, a curved HEI or points distributor, stock OEM intake and Quad-jet. Block and replacement heads should be check for cracks. A .030 overbore will take the displacement to 406 ci.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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Steeno
Tribal Scout

USA
3 Posts

Posted - 27 May 2017 :  3:41:07 PM  Show Profile  Reply with Quote
Bill, I appreciate the reply and info.

So, my best bet is to ditch the heads and build up on an undesirable block. Hmmm.

I found a long block (no intake): Block code 9790071 YF block with "15" heads. The gentleman claims it is a 340 HP '68. The funny thing is a pic he provided shows a "D10" near the distributor hole. I read this as April 1st, 1970?

He claims it has 150+ compression all around. He wants $3000 OBO. It's on an engine stand. He's 2 hours away.

Any advice? I'm not sure how to verify if long block is good and what is reasonable to offer.

Thanks for the help.
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tjs44
Cochise

USA
413 Posts

Posted - 27 May 2017 :  5:49:13 PM  Show Profile  Reply with Quote
if your not going to race it or put a stroker crank in it that block should live fine on the street.Just build it to a 9.5 CR RA III engine and you will like it.IMO $3000 for a truly unknown engine is not a good buy.To me a used engine is worth only the some of the used parts with rods and pistons unless forged have virtually no value.Good luck with your project.FWIW worth I built a 600 HP 557 block that is just street driven a few years ago.Never raced and is still living fine in a 69 GTO.Tom
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Steeno
Tribal Scout

USA
3 Posts

Posted - 27 May 2017 :  6:38:59 PM  Show Profile  Reply with Quote
Tom, I really appreciate your input. Bill was saying much the same I think. I suppose step 1 is to get it pulled and over to my local machine shop/engine guy. In the meantime I'll educate myself more.

Thanks a bunch!
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cortcomp
Coyote

USA
5338 Posts

Posted - 27 May 2017 :  7:07:40 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
It cost me like 2500 to have my 455 totally redone, and that was balanced, with a sleeve, and assembled. For 3k it better be on the stand, clean, and come with paperwork. Even then i'd be nervous, even the best shops make mistakes and what recourse do you have?
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