3.0 headers on a 3.4? Header info please :)

[4RunnerChaos]

Oops.! Learning a little more every day thanks to the_kid

 

[Ed_C]

Won't work,they have different exhaust port designs.

Those guys swapping to 305 headers probably gained power because their existing 350 headers are too big for what they're running.

Backpressure won't increase compression. If any burnt air/fuel mixture actually makes it back to the combustion chamber you'll lose performance and probably misfire or knock,like when a EGR valve gets stuck open.

 

[Skinfaxi]

Won't work,they have different exhaust port designs.

Those guys swapping to 305 headers probably gained power because their existing 350 headers are too big for what they're running.

Backpressure won't increase compression. If any burnt air/fuel mixture actually makes it back to the combustion chamber you'll lose performance and probably misfire or knock,like when a EGR valve gets stuck open.

Agreed. It's not about smaller headers, it's about properly sized, properly designed headers. 350s are one of the most produced engine platforms out there. There are a billion configurations, you can't really correlate results from a small percentage of frankenstein part-swapped 350s to a Toyota V6.

 

[the great him]

Got a couple questions...

So from what I've read about small block Chevys on their forums about putting 305(5.0) headers on a 350(5.7) the lower flow rate increases back pressure which in turn increases compression which improves low and midrange performance.
Which made me think, would the headers from a 3.0 give the same effect? If so.. Wouldn't this also (slightly) improve fuel mileage?
Yes I know she'd lose the top end performance.. But if I can pick up a set of them for cheap why not try.. If it causes too much of a loss on the top, just reverse it!
(Excuse my lack of knowledge in areas, I'm still learning!)
Any information on the 3.0 or 3.4 exhaust manifolds and headers would be greatly appreciated. And thanks in advance for hearing out my off the wall ideas.

they are not swapping the headers, they are swapping the heads... big difference. and it increases compression but not by how you are describing it. the 305 heads have a smaller dome, thus making a smaller space to fit the same volume... its a cheap way to get some power, but its not a good way to get power... if you ever start building that motor to make more power than stock you will soon blow head gaskets and or have other issues. this will work with a stock motor but not one that is being built. the correct way to build one of those would be to keep the 350 heads and build the motor to exploit the potential of the stock heads. -the more space in the 350 heads domes means more space for bigger valves...

and no you can not swap 3.0 heads or headers onto a 3.4 sorry

 

[4RunnerChaos]

they are not swapping the headers, they are swapping the heads... big difference. and it increases compression but not by how you are describing it. the 305 heads have a smaller dome, thus making a smaller space to fit the same volume... its a cheap way to get some power, but its not a good way to get power... if you ever start building that motor to make more power than stock you will soon blow head gaskets and or have other issues. this will work with a stock motor but not one that is being built. the correct way to build one of those would be to keep the 350 heads and build the motor to exploit the potential of the stock heads. -the more space in the 350 heads domes means more space for bigger valves...

and no you can not swap 3.0 heads or headers onto a 3.4 sorry

Thanks for the correction, and my apologies for misenterpereting what they were saying, and mixing parts up. Shoulda read tht more thoroughly.!