Just wondering if headers would help performance. Already have emi thunder straight out the transom . Engines are 450 hp 454s. Thanks Larry

Probably Not. Once you start other mods (Cam, Heads, ect) then they will benefit more. on a pretty stock motor the gains wouldn't be noticeable. especially for the Money they cost...

5k/pr. Cam and heads?

Already have heads cam etc.engines are same as hp500 except 454 cu inch

I think what he means is more radical cams and heads... 500s are pretty mild engines compared to some other equipment. So you won't see much if any hp gains because your build is relatively mild (no offense). If you had 10:1 compression, aluminum cnc heads, a 630-650 lift cam or maybe a huffer then you would benefit from headers over a manifold design.

For the money for headers you could bolt on a set of 177 blowers leave the manifold exhaust and make to a ton more hp. Just my .02

How reliable are blowers? No offense taken these motors are no killers

You dont need headers and you dont want header headaches. As for a blower, 525sc's were a 454 with a 177 blower and were dependable good motors. That said if I was going to stick a blower on it wold be a 250 vs. a 177. Less of a heat pump and you wont have to spin them as hard.. But before you think about a blower, what do you have for a bottom end? If you started with a mag your good, if its a 2 bolt main cast crank 330 your really rolling the dice.

I agree that 250s are better blowers but they are also more expensive and if we were talking dollar for dollar with the $ for headers 177 will fit into the budget alittle closer then the 250s. I mean if $ didn't matter then we could just drop some merc 1350s in there and be done. (Boy did this escalate quickly)

And it also depends what kind of power he wants to make. The stock 525sc engines were good performers and had good longevity but I feel the 7.5:1 compression and the weak camshafts were definitely limiting them from the factory. A roller conversion and a slight bump in compression with the 177s make over 600. Obviously the 250s would make more hp with the same work but just like above how far does he want to go?

Also as stated above blower motors can be very reliable. A good platform to build on and a good fuel/oil system will be money well spent. Also having them properly tuned is worth every penny.

Engines have good rods steel cranks 4 bolt mains edelbrock allum oval port heads hp 500 cam and carbs .550 to600hp would probably get me where I'd like to be. Was just wondering about headers....thought about bigger cu inch.... wasn't thinking blowers. Till now lol

Headers = headaches