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Old 08-20-2010, 08:20 PM
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454 Exhaust Manifolds...What do you think?

Hey guys I gotta question. As some of you are aware I am about ready to drop a 468 big Chevy into a Chevy Luv truck. I rebuilt the entire front end and put in some heavier torsion bars to handle the additional weight. I moved the firewall back about 5 inches to make a little more breathing room in the engine compartment.

I know I am going to have a very tight or impossible fit for most headers (even the shorty block hugger headers). If all header options fail and it becomes too cost prohibitive (at this point) to have some headers fabricated from scratch, what do you guys think these exhaust manifolds http://cgi.ebay.com/ebaymotors/83-84...ts_Accessories would flow for the following motor:

468 BBC
Reworked 781 casting heads with stock valves and a 5 angle valve job
Cam is a hyraulic flat tapped Lunati Voodoo 262 duration / .530 lift cam
(#60202)with matching valve springs
RPM Performer Air Gap Intake
750 Holley VS with horn cut off
TH350 with 2200 stall
Dana 3.73 posi rear end

I know large diameter headers would be the best bet and I will eventually have some custom made, but in the interim I was wondering what you guys think about these exhaust manifolds and their flow numbers or lack there of. I am open to any other suggestions that you guys may have.

Thanks.

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Old 08-20-2010, 09:44 PM
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I can't give you flow #'s, but I can pass along a little info from someone who tested this on a dyno. Joe Sherman(of Edelbrock, Popular HR magazine Inaugural Engine Masters Competition winner, and of course Joe Sherman Racing Engines) reported a 101 hp loss putting manifolds on a 560 hp BBC in place of headers. Now I can't say this is the norm, or if there is differences in BBC manifolds, but I would bet you will lose at least 60hp to the manifolds, and it is likely to be more.

Ever consoder building your own?? Schoenfeld Headers sells all the parts really reasonable. It isn't that hard if you take your time.
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Old 08-20-2010, 09:49 PM
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WOW! Didn't realize the HP loss could be that much. I was thinking more along the lines of 20-30 HP (which is still alot). I think I will probably have to end up building my own Eric, or modifying a set of block huggers or shorty headers. Luckily I know a guy that is an expert welder and I am sure he could do a good job. Just don't know really where to start, but I guess a kit is probably going to be it.

Thanks again for your input. I always appreciate your insight.

Brent
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