Are headers good for low end torque?

If you go to headers, I think the most important thing is to use good gaskets. My 289 Mustang has Tri-Y's right now, and I'm actually thinking about switching back to manifolds. I do have a set of Percy's "Seal-4-Good" header gaskets on there, and I've had the headers off three times and reused them with no problems. I'm not sure if they make them for Buicks though...

 

Short answer..

Yes


Anything that promotes cylinder filling, which headers do, will improve torque. Due to the the physical construction differences between our available exhaust manifolds, and headers, manifolds will always be back-pressure. Headers provide a scavenging effect.

Performance-wise, manifolds will never be better than headers. But there are other considerations, as was previously noted in this thread.

Most entry level performance modifications do enhance torque across the entire operating range of the engine, that is how they improve Horsepower.

Only when you start adding radical cam timing, and large volume cylinder heads and intakes do you "hurt" low speed torque output. The torque is not diminished overall with these mods, just moved to a higher rpm range.

Now how much difference is a another question.. with an otherwise stock engine, it would not be the first modification I did, but will provide significant power increases, when you start talking about an intake/head/cam package.

JW

 

I recall some time back with some dyno simulator results that a high lift short duration roller cam yielded some very impressive torque results.
Anything that increases the camshaft's ability to concentrate power in a narrower powerband will give the most power: increased ramp rates, lift, tighter LSA, etc. along with the rest of the engine's ability to move the air with the camshaft and keep velocity up.

A special note on the stock camshaft however: the cam was engineered with other things in mind besides power output--longevity, gas mileage, emissions compliance, and a wide powerband--all of which are harsh strikes against the engine when trying to maximize power output.

Fortunately, the engineering built into it to help with valve seat longevity also helps with power output because the valves are slower to close than they are to open, which makes it much gentler on the valves and seats.

This results in the valves staying open longer than with a typical symmetrical lobe design, which means it doesn't need as much lift to accomplish adequate cylinder fill.

Symmetrical lobes need around .450 lift to accomplish this.

Torque grind aftermarket camshafts will lose horsepower over the stock cam, while only gaining meager torque numbers, and within a much tighter powerband. Not worth it to me, but if someone's trying to milk as much torque out of it, an extra 5-10 ft. lbs. will look good on the dyno, but won't really be felt much in the real world.

Stock cams were engineered to function optimally within the stock environment, so adding other extras like larger valves, port work, small tube headers, etc. will warrant a larger lift cam to take advantage of the extra air flow potential.

Two main paths for accomplishing the high torque Buick 350:

1) KISS (keep it stock stupid) using everything that was originally intended for the engine from the factory, along with high compression pistons, runner cleanup and exhaust polish, properly matching the compression to the intake valve closing point for 7.5-7.75 dynamic compression ratio, and cleaning up and polishing the exhaust manifold runner ports and exit port. The stock cam is plenty adequate for this combination, and you don't have to sacrifice upper end power, gas mileage, or longevity. Research has indicated torque output of around 392-406 ft. lbs. with this combination.

2) Roller cam combo with high lift, short duration, high velocity head port work, and small tube headers (1 5/8" primaries) has shown big block torque figures (in excess of 450 ft. lbs.), but be prepared to spend some money...

Remember to work with the original engineering intent, not against it. :TU:

Gary

 

Gary

Good to hear from you. How have you been

Paul

 

Gary, glad to see you on the board :TU:

 

X3! Welcome back bro.

And Gary, with the aluminum heads and S/P intake soon on he market there will probably be slightly used sbb 350 roller cams for sale for great deals in the coming months or years so you need to get your "stock" sbb 350 roller designed.

Plus there are a lot of inexpensive sbc tie bar style roller lifters on ebay, with a little pencil grinder work making the tie bar slot a little longer(because Buick lifter bores if I remember correctly are about .125" closer together)will make those work. I'm sure with a mild low lift roller cam the stock rockers can be used as well.:TU:

Just remember, a roller cam is a one time charge the more expensive oil and or the oil additives is for the life of the cam every time the oil needs changed.o No: (its like you never left:moonu:, welcome back bro):Brow::laugh:



Derek

 

Like i said at the start of the thread the stock cam is pretty darn good for low and mid rpm.... Nice to hear from you Gary, we need your input around here with the new heads and intakes coming out!

 

I'm sorry to distract from the thread, but x2 its good to hear from you again Gary.

 

Wow thanks guys!

Been busy as heck, but the Buick dream is getting closer to a reality!

Gary