360 engine/ headers?

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sterrill

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Looking for some opinions from folks who have more experience.
I've got a Dodge 5 ton Winnebago with a 360 engine & higher cams cuz it's in a class C winnebago. Still have the original Holley 2bbl carb in it. Just put a new crate engine in, and got talked into putting headers on instead of the stock exh mnflds that I still have on hand. I've lost a bit more gas mileage here and I'm wondering if the headers were a mistake... Does the 360 want/need that bit of backpressure from the stock exh manifolds? Any ideas?
 
Even though I have read many posts where headers improve fuel mileage I can't say I've seen much improvement from the vehicles I installed them on. Usually stays about the same to just slightly better. Mainly just power improves. I did have one that lost mileage as you say yours did. Turns out it must have been jetted right on the edge of lean with the stock manifolds so when I put the headers on it was really lean. So lean that the throttle had to be pressed farther down to get it to go. I jetted the carb 2 sizes richer and the fuel mileage went up to where it originally was and the power increased dramatically.
 
Exactly as FB says. The motorhome would be tuned to be on the edge of lean in order to get the most out of gas mileage for such vehicle. Reducing the pack pressure with headers and no other change would surely lean it further and mileage would suffer. Power may be up some but, with no tuning to account for the tuning and lean condition, probably not my much.
 
mopowermatt said:
How about some good headers for my 64 dart with a 360?
Click to expand...
They are expensive and have 1-5/8 primaries and 2-1/2 collectors, but I bought a set of Dougs D-450 headers for my 66 and they are really nice.
 
give a call to tti industries.there headers are great,a bit on the spendy side but well worth it once there installed.
 
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