I'm lloking for a way to incease torque in my SB 408, do you have any ideas ?

Here is what I have..

408 ci
Indy 360-1 heads milled to 55cc ported to 343 cfm
Indy intake
10.8 cr
255*/263* solid roller cam ,1.6 rockers .640 lift
1 3/4 headers 3in pipes
electric fan and water pump
950 main body carb
dynoed at 606 hp and 553 lbs tq


Dan

How much more torque do you want and how big is your budget?

Adding cubic inches is one way, adding compression is another. NOS is probably the easiest way. A supercharger will also add a lot of torque.

How much more are you after?

Add another point of compression. With that much duration and aluminum heads it should be fine on pump premium. I have run that much with smaller cams and iron magnum heads with real tight quench.

Also where is your cam degreed to? What is the LSA? Seems like a ton of EX duration compared to intake... Shorter EX duration should give a little more burn down time and a little less overlap.

Sometimes a tappered carb spacer adds a few pounds of TQ on the cheap.

Thinner oil maybe... what are you running?

Put it on alcohol

collector extensions.
edit sorry I see you have pipes.

Loosen the valve lash. If the car seems to respond, maybe a 1.5 exhaust rocker. How long are your primary tubes? Carb spacer?

IMO, your combo has plenty of torque for its build. NA, you need to add More comp, advance the cam, or just add more CI, with the before mentioned mods. Also, longer Pipes, maybe. 3 "s aren't to long. But your primary 1.75" diameter isn't very large either for your HP

I have a 2in spacer

If I could get 10 more lbs of tq.....

Open,???, replace it with a 4 hole tapered.

Maybe a 1" 4 hole tapered spacer on top of a 1" open spacer would help increase bottom end throttle response. The 950 might be a little large for the engine to handle out of the hole. Maybe you could even borrow an 850, just to try. I ran a mild 388 Brodix head Chevy in a Mustang for several years with some friends. Always had a 850 on it. Picked up 3 tenths when we switched over to a 750.

What tranny are you running? If automatic increasing the first gear ratio will increase the torque to the rear tires, same thing in second gear also, not so in third IHTHs

I'm running a 904 with a low gearset..

What is it that you want to do with more torque? Is it quicker acceration or something else Tall tires reduce the gear multiplication and shorter ones increase it, same thing on torque converters, a 8 inch will multiply torque around 3.25 to 1 ratio in low gear and a larger nine or ten inch supposedly will make it less, around 2.7 to 1 according to a magaizine article written many years ago

What quench clearance are you running? Could be as easy as tightening up the quench/compresison and the TQ will increase across the RPM range.

What's the lobe spread and intake centerline? If you're looking for more torque you're probably not using up all your gear at the stripe so that would generally benefit from an earlier (+4 to 6 degrees advanced) ICL. That would hit the converter a little harder out of the whole and advance the torque curve ~300-400 rpm sooner all else being equal.

Not a huge cam but the big indy port might still be a little lazy for your weight and gear. Talk to Mshred, he had a similar combo in a fairly heavy A-body. 3" collector is going to limit your peak torque RPM with a big head but you don't have a lot of Compression either....I'd start with an 8-10" collector extention to see if it helps velocity below the peak without hurting it much more above it.

What is your 60ft and 1/8 ET and mph. And weight. My 360-2 heads flow about the same as yours and compression is the same. My cam is close also except for lift (255/266 @.050) But my motor is a 394 ci. I was running a 950 but switched to a ProSystems 1050 dominator. So far it has picked up about a tenth and 2 mph in the 1/8. It made 533 torque on dyno.

The cam is installed at 106* ICL

Average 60ft is 1.32, 6.42 sec 1/8 mile, no mph....

I was thinking of a smaller carb for ET's......

Yes I want quicker acceleration !!!!!!!

Put a turbo on it.

That 60 ft. times is outstanding I know some very successful NHRA SB Mopar stocker racers that would kill for those 60s The 1/8 miles times don't seem to jive with those 60. ft times to me How about some of the other SB racers on here, how does his 60 ft compare to yours? I'm thinking that the motor is running out of fuel in the upper gears, maybe not

I don't know.....I recently changed the fuel line to a 1/2in....but does seem a bit slow in third...

you tell me..