My '78 L82 is stock and runs very stong. I would like to add 25% more HP to it on the cheap. Any ideas?
Steve

 

Tune up, re-curve distributor and dual exhaust or high flow cat. Anything else is a waste or just Bling (shinny stuff).

Save your money for a set of heads and cam when you have time and cash to buy HP.

 

HP on the cheap, boy wouldnt we all. First thing would probably be to go with a true dual exhaust system without the cat, and rejet the carb for the changes. Maybe open up the air intake breathing, making sure you're grabbing in plenty of cold outside air. From there, things will get pricey. Have a friend with a 79' L-82 4 speed that did all that, plus a Keisler TKO 5 speed upgrade with lower 1st gear. Runs pretty strong, but my daily Pontiac GXP would probably show it tail lights.

 

Nitrous Oxide.

 

Tune-up, recurve dizzy will get you 10-20% increase (from what your present set-up has...that may not be any increase from what ideal factory condition would produce); better breathing heads (reasonably priced cast iron units are available) and matching cam (still using hydraulic lifters) will easily get you there and beyond.

But, tune-up, dizzy recurve and 2-1/2" dual exhaust system will do pretty well alone.

 

agree with distributor Carb and exhaust. headers too. if you have the ability, advance the cam timing 4 degrees with a double roller adjustable timing set and maybe pocket port the heads. yes new heads and cam would likely be better but if money is a concern, and you can do the work this will definitely do the job. we had several L-82 vettes well into the 13's set up like this. some will tell you that 13 second cars aren't that feast anymore but i have a neighbor with a z06. Corvette that I'd bet would run a 15 second time because he's a moron and doest know how to drive. good luck

 

Tweek the carb, recurve the distributor, add true duals with good mufflers and if you still don't think it has enough zip, you can always change the stock rear end gears to a 3.73 ratio...........I think it has a 3.36 rear from the factory but am not 100% sure.

 

3.55s more likely.

I'd suggest pulling the TH350 out - stick in a 700R
Make your @ss end think its got 4.60 gears with the better 1st gear.
30% more torque right there. Don't need to change nothing else.

 

After recurve and true duals, it's a lot easier to cut WEIGHT off of the car, than it is to increase power, if money is an issue. Unless you go vortec heads, decent heads aren't cheap. I did the vortec head swap, and if I had it to do over again, I wouldn't have, I woulda saved my money for aluminum. Cost me just a hair over 1 grand, plus a lot of down time for the car. Lot's of "while you're at it" type of stuff. Like, why change the intake, and NOT swap heads? And hell, if you're doing all of that, better get a new cam and lifters, right? Before you know it, you also need a new water pump and rad to keep that stuff cool.


My advice is to wait till you have a budget to do something that will yield REAL results. I figure after my top end rebuild, super budget, I have MAYBE 250-275hp to my rear wheels. (On a cold day, with the wind blowing JUST right, lol) Which is more than you're hoped for 20-30% power gains...and it's almost negligable, because of the weight of the car, and a crappy 3.08 rear gear combined with a wide 1st gear in my 4 speed. And I have done a LOT to reduce the weight of my car. Now I've learned my lesson, wised up so to speak, and am saving/planning out for a 383 build that will yield me 350 to the rear wheels, minimum.

In the mean time, a 3.55 rear gear will provide a MOST welcome seat of the pants difference in acceleration. Is your car auto or 4 speed, and what rear gearing does it have? A switch from 3.08 to 3.55 is like an instant 25% boost in hp, in terms of git up and go. I'm not trying to sound negative or anything, I just feel like these budget top end rebuilds are...never going to be enough for a proper driving enthusiast. You wanna go fast, just like me, right?

 

i'm not sure changing to taller rear gears would make any difference in acceleration. it's not hp that accelerates-it's torque. that being said, a higher hp motor will also have more torque.
in a dragracer the idea is to be red lined in high gear at the finish. the idea is to have maximum torque multiplication throughout the race. a friend of mine runs a 5.78:1 differential.
but in a street car(for other than the first few feet of travel) simply being in a lower trans gear will give you the same torque multiplication. that is, be in first rather than second when you want to nail it. i've got 3:36 in one sb, 3:55 in another sb and 3:70 in my rat. i know for a fact(not that i ever tried this, though) the 3:36 will keep up with the rat, up to a point, if the sb is in a lower gear. just because the lower gear produces more "leverage" to twist the tires.