Open headers on a 350, will it cause problems?

[chevy80c10]

I just put long tube headers on my 350 (84 shortbed). I was wondering if running them open till i get to a muffler shop will screw up my valves? Do i need to change the timing at all while doing this? Dont want to burn up my valves, and dont want the motor to backfire and possibly catch on fire lol.    I've been scouring the internet trying to find a direct answer and no luck. Thanks for any help.

[csdineley]

I did it earlier this year without any problems. I was a little worried about it as you are. But I drove the 15 miles to the local muffler shop. And other then losing my hearing because it was LOUD everything went fine.   

[Irish_Alley]

you will be ok, you will get the cops attention along with everyone else. you will lose performance due to lack of back pressure. so it will take for pedal to get moving which will make it even louder. mine have been open for 3 years? or so. granted its primary a mud truck but that doesnt mean it doesnt get driven on the road

[sbx22]

I did the same thing as you, drove with open headers to the muffler shop where they then welded my system together. I did take the backroads because I didn't want any attention from cops.

[Irish_Alley]

i been threw a couple dui/seat belt check points with open headers they just take a step back and laugh

[Powerdriver1958]

Maybe back in the 50s and very early 60s it might have been a problem but most guys and gals at any race track never give open headers a second thought . The only reason I ever heard was the draft of cool air after you shut the engine might hurt the valves cooling too quick . That is apparently a wife's tale being as my play truck has never seen a muffler , tail pipe or any other sort of sound control

[chevy80c10]

thanks all for the insight, thats wives tale still lives strong lol thats what had me worried, and as for sound, i got earplugs   thanks guys!

[HAULIN IT]

you will lose performance due to lack of back pressure

Speaking of Wives tails...

[chevy80c10]

welli ran it with the headers open, really wasnt as loud as i thought it would be, she ran fine thanks yall for the motivation haha

[Irish_Alley]

haulin- idk about a wives tail there. but when i cut my cat off my 86 and put a straight pipe in its place i lost low end tq. maybe gained high end. maybe with proper timing/tuning it would of ran better but i know there was a difference in power from before and after. in the low rpms you need to maximize the savaging effect (back pressure) while higher rpms you want to run as free as you can. now if we talk about drag cars yes you want open headers because the amount gas velocity you pushing threw. if your truck is sucking in more air it needs to push out more air than a stock motor thus you open the exhaust up. now i probably should of elaborated more on my original post but i was just stating what i found from hand on experience. even in mini sprints, (4 cylinder Kawasaki motor) took the exhaust packing out of the muffler and lost its power. imo too big of exhaust will hurt a engine this is why a 4 cylinder car has about 1.5 pipes while trucks can have 2.5. but if your moving more air i.e. supercharger/turbo you want at least 2" on that 4 cylinder. You must balance flow capacity with velocity. take Ferrari for example, they have a system that restricts low end and one you reach a higher end it opens a second exhaust path.

[winky]

^^ guy I knew cut the exhaust off a 4 cyl mustang one time and no lie it couldn't pull the main hill in town without just about stalling lol back pressure is a real thing. Its more important on the newer vehicles than the older ones. I also noticed when I ran open headers on my 77 it shifted funky (th 350 vacuum modulator) guess it messed with the vacuum some too.

[Pescados666]

I was with a friend in his 96 ford ranger when the tailpipe fell off.  Instantly felt a loss of power when it happened too.  Back pressure definitely makes a difference lol

[Irish_Alley]

man whats up with you guys thinking fords have power to begin with lol j/k

[rich weyand]

Oh, I don't know.  My dad's 1975 F-250 did OK with a 462 Lincoln engine (stock from the factory!).

[Irish_Alley]

rich dont get me wrong. i love american trucks/cars but im just a chevy guy lol and ford is "blue oval bad" but i do give credit where its due, just wont admit that ford are better than chevys ;-)