140 hp and 240 tq stock, what would the numbers be with hedman shorty headers and a perfromer intake manilfod. Also a edlebrock 600 carb. I'm guessing 165hp but not sure on the torque?

 

Headers/intake/carb with no other mods should get you probably 165 HP and 265 lbs/ft. maybe more.

 

Likely a lot more...
I'm running an 84 LG4 (150hp stock) with Hedman shorties, their Y-pipe; Dynomax catback, stock cast-iron intake and the stock non-CC Q-jet with DR secondary rods and an N hanger. It has a 'small' cam in it, .420" lift intake and exhaust. Engine has just under 250k miles - the heads have never been off it - and it runs around 98.5 in the ¼ mile. Weighing about 3400lbs, that calculates to approximately 275 HP.
I wouldn't be too surprised to see near 200 HP with your additions.

Pete

 

You have to be careful about getting horsepower from your 1/4 time and MPH. The formulas don't take into account rear gear ratio, trans type, 60ft time, ect. Keep in mind that I can go from 2.73s to 3.73s and run a full second quicker in the quarter. If I did calculations before and after it would say I gained 100 horsepower! I didn't, I just used the engine's power more efficiently.

Don't get me wrong, this is a great set of upgrades for your car, and will make it a lot more fun to drive, but don't expect miracles without doing head work and a bigger cam. All of which needs to be matched to the right compression ratio.

 

Hp doesnt really matter. Its the whole car combo that gets down the track. With a properly tuned 305 you should be able to get into the high 13's low 14's and still be streetable.